CHANGES.md

Release 1.12 -- ?? (compared to 1.11)

Dependency and standards requirements changes:

• The minimum (and default) compilation mode is now C++14. C++17 and 20 are also supported. #1362 #1369 (1.12.2)
• Minimum compilers are now gcc 6.1 (no more support for gcc 4.8), MSVS 2017 or newer (no more support for 2015).
• Minimum LLVM is now 9.0. Support for LLVM 7 and 8 have ben dropped. #1441 (1.12.3)
• Minimum OpenImageIO is now 2.2: Support for OIIO 2.0 and 2.1 have been dropped. #1426 (1.12.3)
• Minimum OpenEXR version is now 2.3 (raised from 2.0). #1406 (1.12.3)

OSL Language and oslc compiler:

• #pragma error "message" and #pragma warning "message" can be used to conditionally inject a compile-time error or warning. #1300 (1.12.1)
• Check for errors when when writing oso files (for example, disk volume full). #1360 (1.12.2/1.11.14)
• A new flavor of gettextureinfo(texturename, paramname, s, t, destination) allows for querying of texture metadata about the particular UDIM tile that will be used for particular (s,t) texture coordinates. #1398 (1.12.3)
• Better error detection when OSL user functions write to function parameters that are not marked as output. #1417 (1.12.3)

OSL Standard library:

• vector2.h is updated with a mod() function for vector2. #1312 (1.12.1/1.11.12)
• Preliminary work for adding standard MaterialX closures. 31371 (1.12.2)
• Fix previously-broken color conversions from RGB to xyY. #1410 (1.12.3)
• Fully removed MaterialX shaders (get those from the MaterialX project). #1450 (1.12.3)

API changes, new options, new ShadingSystem features (for renderer writers):

• Custom experimental llvm optimization levels 10, 11, 12, and 13. These are stripped down versions of 0, 1, 2, 3 (corresponding to clang's -O0, -O1, -O2, -O3) but we think for shaders are just as performant but with lower JIT time. These are currently experimental, but we are benchmarking to determine if they should be the new defaults. #1250 (1.12.0.0)
• ShadingSystem attribute "searchpath:library" gives a searchpath for finding runtime-loadable implementation modules for ISA-optimized operations. #1310 (1.12.1)
• Output variable placement -- now you can designate where shader outputs should go and the shader will put results there, instead of the app using find_symbol() and symbol_address after the shader is executed. #1328 (1.12.2)
• Userdata input placement -- now you can designate where interpolated userdata should be copied from directly, rather then via callbacks to RendererServices::get_userdata(). #1391 (1.12.3)

Continued work on experimental SIMD batched shading mode:

• Added support for masked operations to LLVMUtil. #1248 #1250 (1.12.0.0)
• Add interface to ShadingSystem for batched execution. #1272 (1.12.0.1)
• Add interface to batched RendererServices. #1276 (1.12.0.1)
• Batched testshade. #1298 (1.12.1)
• ShadingSystem plumbing to support batched execution. #1301 (1.12.1)
• Batched analysis to figure out which symbols need to be varying or uniform, and which operations require masking. #1313 #1318 #1322 (1.12.1)
• Additional infrastructure for batched analysis. #1316 (1.12.1)
• Add implementation for BatchedBackendLLVM. #1330 (1.12.1)
• ISA-specific modules. #1345 (1.12.2)
• Introduction of CI testing of batched mode. #1357 #1367 (1.12.2)
• Control flow and string ops. #1372 (1.12.2)
• Matrix operations. #1378 (1.12.2)
• Batched algebraic, trig, and transcendental functions. #1385 (1.12.2)
• Batched noise. #1394 (1.12.3)
• Batched implementation of all color operations. #1408 (1.12.3)
• Batched bitwise ops. #1413 (1.12.3)
• Batched spline and spline inverse. #1422 (1.12.3)
• Batched texture, gettextureinfo, texture3d, environment. #1436 (1.12.3)
• Batched dictionary functionality (dict_find, etc.) #1445 (1.12.3)

Continued work on experimental OptiX rendering:

• Explicitly set the OptiX pipeline stack size. #1254 (1.12.0.0)
• CI tests now at least compile and build with USE_OPTIX=1 (though not yet run the tests). #1281 (1.12.0.1)
• A simple self-contained Cuda/OptiX example has been added as testsuite/example-cuda. #1280 (1.12.0.1)
• Overhaul in how strings are communicated to the GPU side. #1309 (1.12.1)
• Removal of runtime compilation of Cuda (libnvrtc dependency eliminated). #1309 (1.12.1)
• Fix problems with unresolved symbols on GPU, particularly when multiple shaders call certain functions like printf. #1401 (1.12.3)
• Changed prototype of osl_get_attribute callback to work properly on GPU. #1404 (1.12.3)
• Fix missing hostdevice modifier on some matrix operators. #1409 (1.12.3)
• Fix race conditions when compiling for OptiX 7. #1411 (1.12.3)
• osl_get_attribute() uses device strings when compiling for OptiX. #1435 (1.12.3)

Performance improvements:

• Less mutex locking around use and retrieval of ColorSystem related to doing color transforms. #1405 (1.12.3)

Bug fixes and other improvements (internals):

• Fix derivatives of texture calls when only derivatives of the "alpha" value are needed. #1251 (1.12.0.0)
• When uninitialized value detection is used, fix possible "false positive" related to the condition variable of do-while loops. #1252 (1.12.0.0)
• Avoid some pointless copies of output variables from a used layer to a downstream layer that is known to not be used. #1253 (1.12.0.0)
• Stats now print more information about build options and runtime hardware capabilities. #1258 #1259 (1.12.0.1)
• The osl and oso parsers are now re-entrant, which allows different threads to concurrently compile or load shaders. #969 (1.12.0.1)
• Fix asymptomatic potential runtime optimizer bug where certain multi-component values were not correctly recognized as nonzero. #1266 (1.12.0.1/1.11.9)
• Fix optimizer bug where an output parameter that is also marked as [[lockgeom=0]], i.e., it gets a value from a userdata input, but also passes it to a downstream connection or a renderer output, could end up with an incorrect value if it was never read in the shader (including if the only times it was read were optimized away). #1295 (1.12.0.1)
• Ensure that OSLCompiler::LoadMemoryCompiledShader returns false upon parse failure. #1302 (1.12.1/1.11.10)
• During runtime optimization, don't merge layers that produce renderer outputs (the semantics of doing so are very fishy). #1296 (1.12.1)
• Eliminate unnecessary error messages to stderr for broken point clouds. #1333 (1.12.1/1.11.13)
• Fix undefined behavior that could result in crashes that resulted from the Symbol class having no virtual destructor. #1397 (1.12.3)
• Fix in runtime optimizer where tracking of messages and unknown messages relied on uninitialized variables. #1447 (1.11.17/1.12.3)

Internals/developer concerns:

• Use the final keyword in certain internal classes where applicable. #1260 (1.12.0.1/1.11.9)
• Minor fixes to the internal TypeSpec and Symbol classes. #1267 (1.12.0.1)
• Switch from deprecated call to OIIO::parallel_image to the new version. #1317 (1.11.11/1.12.1)
• The "archive_groupname" handling is now careful to sanitize the filenames it deals with, closing some security and safety holes. #1383 (1.12.2)
• More migration of string formatting to new std::format style. #1389 (1.12.3)
• llvm_util: Switch some uses of ptr+len to span. #1390 (1.12.3)
• OSL no longer uses sscanf internally (which has icky locale-dependent behavior), and instead use locale-independent OIIO::Strutil utilities whenever we need to parse strings. #1432 (1.12.3)

Build & test system improvements:

• CMake build system and scripts:
  • We now use .git-blame-ignore-revs to record commits that consist entirely of reformatting, so that 'git blame' does not misattribute authorship to the trivial changes of those commits. #1244 (1.12.0.0)
  • Miscellaneous improvements to cmake scripts. #1247 (1.12.0.0)
  • Instead of defaulting to looking for Python 2.7, the OSL build now defaults to whatever Python is found (though a specific one can still be requested via the PYTHON_VERSION variable). #1249 (1.12.0.0/1.11.8) #1286 (1.12.0.1/1.11.9)
  • Extend checked_find_package with VERSION_MIN and VERSION_MAX. #1303 (1.12.1/1.11.10)
  • Make the CMake build scripts more friendly to being a subproject. #1304 #1319 (1.11.11/1.12.1)
  • We weren't properly hiding non-public symbols. #1337 (1.12.1/1.11.12)
  • Fully split oslquery and oslnoise libraries from oslexec, no more redundant modules put into both. #1346 #1348 (1.12.1)
  • Support for CMake 3.20 #1354 (1.12.2/1.11.14)
  • Important change to Makefile wrapper: We have a 'Makefile' that just wraps cmake for ease of use. This has changed its practice of putting builds in build/ARCH to just build (and local installs from dist/ARCH to dist) to better match common cmake practice. So where your local builds end up may shift a bit. #1396 (1.12.3)
  • Be more careful about not writing over a sensitive install area unless CMAKE_INSTALL_PREFIX is explicitly set. #1421 (1.12.3)
  • PROJECT_VERSION_RELEASE_TYPE and OSL_SUPPORTED_RELEASE are now cache variables that can have build-time overrides. #1443 (1.12.3)
  • Use PROJECT_IS_TOP_LEVEL (not OSL_IS_SUBPROJECT) to confirm with CMake 21 conventions. #1443 (1.12.3)
  • New TIME_COMMANDS option, when enabled, can help debug performance of the build. #1443 (1.12.3)
• Dependency version support:
  • Build properly against Cuda 11 and OptiX 7.1. #1232 (1.12.0.1)
  • PugiXML build fixes on some systems. #1262 (1.12.0.1/1.11.8)
  • Cuda/OptiX back end: Add __CUDADEVRT_INTERNAL__ define to bitcode generation, needed to avoid duplicate cudaMalloc symbols with CUDA9+ #1271 (1.12.0.1)
  • Build against LLVM 11 #1274 (1.12.0.1), LLVM 12 #1351 (1.12.1.0) #1412 (1.12.3), LLVM 13 #1420 (1.12.3)
  • Fix build break against recent OIIO master change where m_mutex field was removed from ImageInput. #1281 (1.12.0.1/1.11.9)
  • Work to ensure that OIIO will build correctly against the upcoming Imath 3.0 and OpenEXR 3.0. #1299 (1.11.10/1.12.1) #1332 (1.11.11/1.12.1) #1341 (1.11.12/1.12.1) #1356 #1368 (1.11.13/1.12.2)
  • Improved finding of llvm components when using static libraries. #1375 (1.12.2)
  • No longer use boost regex, completely rely on std::regex now that OSL is C++14 minimum. #1377. (1.12.2)
  • Support for OpenImageIO 2.3 changes. #1393 (1.12.3)
• Testing and Continuous integration (CI) systems:
  • Eliminate the old Travis CI and Appveyor. #1334 #1338 (1.12.1)
  • Use ccache + GitHub 'cache' action to greatly speed up CI runs. #1335 (1.12.1)
  • Divide the CI stages into separate steps, combine dependency-building scripts for CentOS and Ubuntu ito a single script. #1338 (1.12.1)
  • CI tests clang11, also batched shading with clang. #1379 (1.12.2)
  • CI speeds up OIIO builds by not building its tests. #1380 (1.12.2)
  • CI tests gcc11. #1381 (1.12.2)
  • Deal with OpenColorIO changing its master branch to "main". #1429 (1.12.3)
  • Fix tests for texture3d now that OIIO has dropped support for Field3D. #1437 (1.12.3)
  • Test against LLVM13/clang13 for the VFX Platform 2022 tests. #1434 (1.12.3)
  • Test against MacOS-11. #1434 (1.12.3)
  • Add testsuite coverage of environment(). #1438 (1.12.3)
  • Use a project-specific environment variable OSL_CI instead of the more generic CI to avoid clashes with other systems. #1446 (1.12.3)
• Platform support:
  • Various Windows compile fixes. #1263 #1285 (1.12.0.1)
  • Windows+Cuda build fixes. #1292 (1.12.0.1)
• The oso and osl lexers/parsers are now given internal symbol names that are fully versioned, to avoid possible clash if multiple OSL releases are both linked into the same application. #1255 (1.12.0.0)

Documentation:

• A simple self-contained Cuda/OptiX example has been added as testsuite/example-cuda. #1280 (1.12.0.1)
• Update CLAs, Charter, GOVERNANCE, particularly after acceptance of new CLAs and moving the repo to the ASWF GitHub account. #1308 #1240 #1314 (1.11.11/1.12.1)
• First steps in new documentation and scripts for building OSL on Windows. #1326 (1.12.1)
• Fix missing explanation of the optional "errormessage" parameter to environment() and texture3d(). #1442 (1.12.3/1.11.17)

Release 1.11.17.0 -- 7 Jan 2022 (compared to 1.11.16.0)

• Fix in runtime optimizer where tracking of messages and unknown messages relied on uninitialized variables. #1447
• Minor changes related to OpenColorIO changing their master branch name to "main". #1431
• Testing: Get texture3d tests operational again. #1437
• Docs: Fix missing "errormessage" explanation for environment() and texture3d(). #1442
• Build/cmake fixes: Make PROJECT_VERSION_RELEASE_TYPE and OSL_SUPPORTED_RELEASE be cache strings, so they can be overridden; change OSL_IS_SUBPROJECT to PROJECT_IS_TOP_LEVEL (and change its sense) to match CMake 21+ behavior; add a TIME_COMMANDS option to help debug performance of the build. #1443

Release 1.11.16.0 -- 1 Nov 2021 (compared to 1.11.15.0)

• Fixes to work with LLVM 13, and to compile with clang 13. #1412 #1420

Release 1.11.15.0 -- 1 Sep 2021 (compared to 1.11.14.2)

• Changes for compatibility with OpenImageIO 2.3. #1393 #1388
• Fix potential crashes (or at least undefined behavior) due to missing virtual destructor of internal Symbol type. #1397

Release 1.11.14.2 -- 1 Jul 2021 (compared to 1.11.14.1)

• Fix warnings that occur when compiling with clang and C++17 mode. #1379
• CI/testing: Additional CI tests for clang+c++17 (#1379), gcc11 (#1381), llvm 12 (#1381), speed up CI builds by not building the testing components of OIIO (#1380).

Release 1.11.14.1 -- 1 Jun 2021 (compared to 1.11.14.0)

• Fix library setup for LLVM installations consisting of static libraries. This fixes a build problem that can crop up on MacOS using Homebrew-installed LLVM 12. #1375

Release 1.11.14 -- 10 May 2021 (compared to 1.11.13)

• oslc/OSLCompiler: Check for errors when when writing oso (for example, disk volume full). #1360
• Fix crash generating closure function calls with LLVM 11. #1361
• Build: LLVM 12 compatibility. #1351
• Build: Support for CMake 3.20 #1354
• Build: Be robust to certain OpenEXR 2.x config fies. #1356
• Build: Fixes to deal with newer OIIO builds that are C++14.

Release 1.11.13 -- 1 Apr 2021 (compared to 1.11.12)

• Updated vector2.h with a mod(vector2,vector2) function. #1312
• Fix unnecesary error messages to stderr when encountering broken point clouds. #1333

Release 1.11.12 -- 1 Mar 2021 (compared to 1.11.11)

• Build: Changes for smooth compile against upcoming Imath 3.0. #1332 #1341
• Build: We weren't properly hiding non-public symbols. #1337
• CI: Cleanup and get rid of the last Travis vestiges. #1334
• CI: Speed up CI runs by using GHA cache + ccache. #1335
• CI: Separate CI process into several individual "steps." #1338

Release 1.11.11 -- 1 Feb 2021 (compared to 1.11.10)

• Build: Make the CMake build system more friendly to being a subproject. #1304
• Build: Improve dependency on Imath/OpenEXR include files.
• CI: Fixes to Mac CI. #1315
• Docs: Update CLAs, Charter, GOVERNANCE, particularly after acceptance of new CLAs and moving the repo to the ASWF GitHub account. #1308 #1240 #1314
• Internals: Switch from deprecated call to OIIO::parallel_image to the new version. #1317

Release 1.11.10 -- 1 Dec 2020 (compared to 1.11.9)

• Bug fix: optimizer interaction with output param that also is userdata. #1295
• Ensure that LoadMemoryCompiledShader returns false upon parse failure. #1302
• Work to ensure that OIIO will build correctly against the upcoming Imath 3.0 and OpenEXR 3.0. #1299

Release 1.11.9 -- 1 Nov 2020 (compared to 1.11.8)

• Build properly against Cuda 11 and OptiX 7.1. #1232
• Windows compile fixes. #1263 #1285
• PugiXML build fixes on some systems. #1262
• Fix asymptomatic potential runtime optimizer bug where certain multi-component values were not correctly recognized as nonzero. #1266
• Fix false positive with "debug_uninit" where certain while loops might be flagged as using uninitialized values when in fact they were not. #1252
• Slightly optimize by not copying output params to layers that will not be used. #1253
• Internals: use the final keyword in certain internal classes where applicable. #1260
• Cuda/OptiX back end: Add __CUDADEVRT_INTERNAL__ define to bitcode generation, needed to avoid duplicate cudaMalloc symbols with CUDA9+ #1271
• Fix build break against recent OIIO master change where m_mutex field was removed from ImageInput. #1281

Release 1.11.8 -- 1 Oct 2020 (compared to 1.11.7)

• Fix broken derivatives of the optional "alpha" return of texture calls when the normal color channels return don't have their derivatives used but the alpha does. #1258
• Building vs Python: instead of defaulting to searching for python 2.7 specifically and needing to set PYTHON_VERSION if you want (or have) a different one, default to whichever version is found. If multiple versions of Python are on the system, you can still use the PYTHON_VERSION cmake variable to disambiguate which one you want. #1249
• For the experimental OptiX support, explicitly set the OptiX pipeline stack size (fixes some bugs). #1254
• ShadingSystem statistics output (which is printed with testshade --help, by the way) now includes information about the SIMD capabilities specified at OSL build time, those available at runtime, and the versions of LLVM, OIIO, and Imath used. This should help in debugging and issue reporting by making it easy to know certain build time choices just by running testshade. #1258

Release 1.11 -- 1 Sept 2020 (compared to 1.10)

ASWF adoption changes:

• GOVERNANCE.md and ASWF/Technical-Charter.md document the project governance and how the Technical Steering Committee works. An archive of meeting minutes can be found in ASWF/meetings. #1137 (1.11.5)
• All the copyright notices now read "Copyright Contributors to the Open Shading Language Project," all files now have proper SPDX identifiers instead of long boilerplate notices, and 3rd party included code now has its licenses documented in the LICENSE-THIRD-PARTY.md file. #1145 (1.11.5)
• The official mail list has switched to https://lists.aswf.io/g/osl-dev #1167

Dependency and standards changes:

• LLVM 7.0-10.0: Support for LLVM 4, 5, and 6 have been dropped. Support for LLVM 8, 9, and 10 have been added. Note that using LLVM 10 requires building for C++14 or later, because LLVM 10's APIs no longer support C++11. #981 #1046 #1058 #1128 #1152 #1162 #1206
• OpenImageIO 2.0-2.2: Support for OIIO 1.8 has been dropped; a minimum of OIIO 2.0 is needed to build OSL. (Additionally, a minimum of OIIO 2.1 is strongly recommended for anyone using the SIMD batch shading mode.) #1038 (1.11.0)
• CMake minimum is now 3.12. #1072 (1.11.1)

OSL Language and oslc compiler:

• New syntax to reference color and point/vector/normal components as named struct components, such as C.r, C.g, C.b, or P.x, P.y, P.z. #1049 (1.11.0)
• oslc compilation speed-ups with faster retrieval of source lines when pasted into oso output. #938 (1.11.0)
• Writing to function parameters not marked as output was only recently properly recognized as an error (it was documented as illegal all along). Now we demote to a warning, treating it as a full error was too disruptive. #944 (1.10.3/1.11.0)
• Improve oso output efficiency. #938 (1.10.3/1.11.0)
• Fix bug related to counting the proper number of values used for array default value initialization. #948 (1.10.3/1.11.0)
• Slight modification to the formatting of floating point values in the oso to ensure full precision preservation for float values. #949 (1.10.3/1.11.0)
• Fix crash when encountering empty-expression for (;;). #951 (1.10.3/1.11.0)
• Fix bug in code generation of certain while loops that directly tested a variable as a zero/nonzero test, such as:

      i = 3;
      while (i)
          --i;
  

  whereas the following had worked (they should have been identical):

      i = 3;
      while (i != 0)
          --i;
  

  #947 (1.10.3/1.11.0)
• Improve warnings about ill-advised use of the comma operator. #978 (1.10.4/1.11.0)
• Fix an assertion/crash when passing initialization-lists as parameters to a function, where the function argument expected was as array. #983 (1.10.4/1.11.0)
• Fix an assertion/crash for certain type constructors of structs, where the struct name was not declared. (This is an incorrect shader, but of course should have issued an error, not crashed.) #988 (1.10.4/1.11.0)
• Improve oslc type error detection for variable declarations with init expressions. Note that this may flag some warnings and errors that went undetected before, involving initialization assignments of incompatible types. #991, #993 (1.10.5/1.11.0)
• Allow shader parameters with empty brace initializers, such as:

      shader foo ( float myarray[] = {} )
  

  Un-lengthed arrays, if they aren't connected or given a concrete instance value, still default to length 1 (we don't allow 0-length arrays, that's a whole other can of worms), but this is now treated as equivalent to = { default_value } (0 for int or float, "" for string). #967 (1.11.0)
• More correct handling of escaped string literals (such as "\tfoo\n") in string and also in string metadata. #1073 (1.11.1)
• New command line argument oslc --embed-source embeds the preprocessed source code in the .oso file itself (helpful for certain debugging situations). #1081 (1.11.3)
• oslc can generate dependency files, honoring the -M, -MM, -MD, -MMD, -MF, and -MT flags with similar meanings to gcc and clang. #1085 #1107 (1.11.3) Example:

      $ oslc -MMD test.osl
      Compiled test.osl -> test.oso
      $ cat test.d
      test.oso: test.osl \
          dist/macosx/share/OSL/shaders/color2.h \
          dist/macosx/share/OSL/shaders/stdosl.h
  

• New shader-level metadata: [[ int range_checking=0 ]] disables the automatic generation of range checking code for the shader. #1112 (1.11.4)
• Support has been added for pointcloud_get() to be able to retrieve per-point string data from point clouds. #1157 (1.11.5)
• Shader output parameters that are marked [[ int lockgeom=1 ]] will automatically bind to any identically-named userdata, just like non-output parameters have always done. #1200 (1.11.6)

OSL Standard library:

• Extend linearstep() and smooth_linearstep() to work with color, point, vector, and normal types (previously restricted to float). #994 (1.10.5/1.11.0)
• Extend transformc() to understand translating between linear and sRGB color spaces. #1013 (1.11.0)
• cbrt() cube root was added to the standard library. #1164 #1166 (1.11.6)

API changes, new options, new ShadingSystem features (for renderer writers):

• ShadingSystem::convert_value() will now allow promotion of int or float to float[4]. #940 (1.11.0)
• Removed the varieties of RendererServices::texture(), texture3d(), and environment() that lack the errormessage parameter and had been marked as deprecated since OSL 1.8. #945 (1.11.0)
• Deprecate the auto-allocation of contexts and per-thread-info. Certain calls that took a Context* pointer that were allowed to be NULL now by convention require the renderer to pass a valid context. #958 (1.11.0)
• ShadingSystem: thread-safe/reentrant shader specification via new varieties of Parameter(), Shader(), ConnectShaders(), and ShaderGroupEnd() that take an explicit ShaderGroup reference and are therefore "stateless" and thread-safe. If you exclusively use these new methods for shader specification, it's possible for multiple threads to specify shader groups simultaneously. #984, #985, #986, #1000 (1.11.0) #1067 (1.11.1)
• New ShadingSystem options:
  • "opt_warnings" enables warnings about things that couldn't be optimized and may be performance issues. #1010 (1.11.0)
  • "gpu_opt_error" enables full error status of the subset of those warnings that are also hard no-go's when executing on GPUs. #1010 (1.11.0)
  • "lazyerror", if set to 0, will unconditionally (and non-lazily) run any shader layers that still contain error() calls after optimization, so that error messages can't be elided by optimizations causing the layer to be eliminated or never run. When "opt_warnings" is enabled, warnings will be issued about shaders that couldn't optimize away all of their error calls. Note that the default value is 1, giving the old behavior or lazily evaluating shader layers that contain error calls. #1191 (1.11.5)
• RendererServices::get_texture_handle() has changed slightly to require a ShadingConntext* parameter, and get_texture_info() has changed to have a parameter allowing the caller to provide a texture_thread_info handle and a context, as well as to provide a pointer to a ustring where error messages should be placed. #1033 (1.11.0)
• The LLVM JIT optimization level (controlled by the llvm_optimize shading system attribute) now defaults to 1, not 0. That should be the best performance while still having reasonable JIT times. #1114 (1.11.4)
• We no longer automatically build the MaterialX shaders (you need to set build option OSL_BUILD_MATERIALX to ON). This will eventually be deprecated entirely. #1136 (1.11.5)
• Helper varieties of ShadingSystem::Parameter() and ReParameter() that handle the common cases of a single float, int, or string. #1195 #1196 (1.11.6)
• ShaingSystem::optimize_group() now takes an optional parameter that allows the caller to only do the optimize step without the JIT step. #1226 (1.11.71)

Continued work on experimental SIMD batched shading mode:

• Continued work on SIMD-friendly math and noise: #1108 (1.11.4)
• Support in LLVM_Util for various wide (SIMD) data types. #1175 (1.11.6)

Continued work on experimental OptiX rendering:

• Build option USE_OPTIX=1 enable experimental OptiX support.
• testshade and testrender now take --optix flags to run tests on OptiX. You can also force either to run in OptiX mode with environment variable TESTSHADE_OPTIX=1. #996 #1001 #1003
• Various fixes to how strings are represented on the Cuda side. #973 (1.11.0)
• More complete support of all the noise varieties. #980 (1.11.0)
• Got spline() function working. #974 #1011 (1.11.0)
• Work towards getting texture calls working. #974 (1.11.0)
• printf works for multiple values. #1007 (1.11.0)
• Work on color-related functions. #1012 (1.11.0)
• Support for native OSL closures. #1028 #1029 (1.11.0)
• Work on matrix ops. #1054 (1.11.1)
• Allow init ops. #1059 (1.11.1)
• Fixes to string closure params. #1061 (1.11.1)
• Add support for OptiX 7 #1111 #1203 (1.11.6)

Performance improvements:

• Constant fold array accesses even if they are out of bounds. #1035 (1.11.0)
• Speed up the concat() OSL function, the new implementation is very careful to avoid extra copies and unnecessary allocations. #1104,#1105 (1.11.3)
• Shader performance improved slightly by better inlining during the JIT. #1114 (1.11.4)
• Range checking of matrix component access is skipped for certain cases where it was unnecessary. #1174 (1.11.6)
• LLVM JIT+optimize time has been sped up around 10% by doing a better job of pruning unused functions and symbols in the generated module. #1172 (1.11.6)
• ShadingSystem::symbol_address() no longer checks for the symbol to be NULL (though it will assert on a debug build). #1237 (1.11.7.1)

Bug fixes and other improvements (internals):

• Fix bug in implementation of splineinverse() when computing with Bezier interpolation. #954 (1.10.3/1.11.0)
• Fix bug in implementation of transformc when relyin on OpenColorIO for color transformation math, in cases were derivatives were needed (this is a rare case probably nobody ran into). #960 (1.10.3/1.11.0)
• Improve thread-safety of the OSLCompiler itself, in case an app wants to be compiling several shaders to oso concurrently by different threads. #953 (1.10.3/1.11.0)
• LPEs: forbid LPE repetitions inside groups. #972 (1.10.4/1.11.0)
• Improve error detection and messages for badly formed serialized shaders. #1026 (1.11.0)
• Fix OSLQuery::init() return value, which was false when it should have been true. #1030 (1.11.0)
• Change the way oslc frees long chaines of nodes, which fixes a possible stack overflow crash for extremely complicated parse trees. #1031 (1.11.0)
• Properly respect the lockgeom default when building a shading group from serialized commands. #1032 (1.11.0)
• Fix runtime crash when optional texture argument "missingalpha" was used. #1044 (1.11.0)
• Fix the implementation of division-with-derivs so that the main value always exactly matches the results of division of values without derivs. Previously there could be some LSB differences. #1066 (1.11.1)
• Fix a number of places that weren't properly "locale-independent". #1075 (1.11.1)
• Bug fix: fix bug/assertion in cases where layer merging tried to combine layers that were "entry layers." #1103 (1.11.3)
• Fix Windows bug where stdosl.h would not be found properly if oslc.exe was in a file path containing a directory name starting with "n". (Because of interplay between Windows use of backslash for directory separtors and C/C++/OSL use of backslash as escape sequences in strings.) #1101 (1.11.3)
• Remove the internal attribute query cache, in practice it seemed to be slowing things down. #1109 (1.11.4)
• debug_nan and debug_uninit work more accurately for matrices -- fewer false positives. #1174 (1.11.6)
• Fix bug that sometimes caused the optimizer to misunderstand which arguments to regex_search and regex_match were written. #1186 (1.11.6)

Internals/developer concerns:

• Switch much of the internals where we do string formatting using printf-like conventions to errorf(), etc., naming convention, reserving the non-f names for future use with C++20 std::format/python conventions. #1076 (1.11.3)
• Remove pointless assertions from the TypeSpec class. #1079
• Assertion overhaul: use OSL_ASSERT/OSL_DASSERT instead of borrowing from OIIO's dassert.h. Note that OSL_ASSERT always tests, prints error if the test fails, but then only aborts for debug builds (no abort for release builds). In contrast, OSL_DASSERT does all for debug builds, and none (not even the test) for release builds. #1080 #1087 (1.11.3)
• Refactor the implementation of the Dual template to support more efficient code generation when used in vectorized loops (this will be important for the upcoming batch shading extensions). #1088 (1.11.3)
• Refactor of much of the Imath replicated code to support better code generation when used in vectorized loops. #1096 (1.11.3)
• Refactor oslconfig.h, split all the compiler/C++version detection and differing macros into platform.h. #1102 (1.11.3)
• Certain runtime error messages have been improved by demangling the names of involved variables and their scopes. #1179 (1.11.6)
• LLVM now JITs code for the specific host architecture. #1182 (1.11.6)
• Change all bare std::ofstream and ifstream to OIIO::ofstream/ifstream. This ensures that they are UTF-8 safe and compile properly on MINGW. #1188 (1.11.6)

Build & test system improvements:

• Major overhaul of the CMake build system to upgrade minimum of CMake 3.12 and us many features that this makes available. #1072 #1074 #1143 (1.11.1+) Highlights:
  • All optional dependencies (e.g. "Pkg") now can be disabled (even if found) with cmake -DUSE_PKG=0 or environment variable USE_PKG=0. Previously, some packages supported this, others did not.
  • All dependencies can be given find hints via -DPkg_ROOT=path or by setting environment variable Pkg_ROOT=path. Previously, some did, some didn't, and the ones that did had totally inconsistent names for the path hint variable (PKG_HOME, PKG_ROOT_DIR, PKG_PATH, etc).
  • Nice color coded status messages making it much more clear which dependencies were found, which were not, which were disabled.
  • Use standard BUILD_SHARED_LIBS to control shared vs static libraries, replacing the old nonstandard BUILDSTATIC name.
  • Use correct PUBLIC/PRIVATE marks with target_link_libraries and target_include_directories, and rely on cmake properly understanding the transitive dependencies.
  • CMAKE_DEBUG_POSTFIX adds an optional suffix to debug libraries.
  • CMAKE_CXX_STANDARD to control C++ standard (instead of our nonstandard USE_CPP).
  • CXX_VISIBILITY_PRESET controls symbol visibility defaults now, not our nonstandard HIDE_SYMBOLS. And the default is to keep everything hidden that is not part of the public API.
  • The ENABLERTTI build option has been renamed ENABLE_RTTI.
  • Config based install and usage.
• testshade:
  • Make sure that no unreported errors accumulated in the texture system or image cache. #939 (1.11.0)
  • Check that no leftover errors are in the TextureSystem or ImageCache at the end of the test (that would indicate that someplace in OSL we are failing to check texture errors). #939 (1.10.3/1.11.0)
  • testshade -o : now null as the filename will not produce any output. This is handy to mark a renderer output but without storing the results as an image. #1193 (1.11.6)
  • --vary_pdxdy, --vary_udxdy and --vary_vdxdy allow a way to force P, u, v to have varying derivatives (for testing purposes). #1227 (1.11.7.1)
• Supporting dependencies:
  • Build script finding of LLVM is now more robust to certain library configurations of llvm, particularly where everything is bundled in just one libLLVM without a separate libLLVMMCJIT. #976 (1.10.4/1.11.0)
  • Support for LLVM 4 has been dropped. #981 (1.11.0)
  • Simplified finding of flex/bison, rely more on CMake's built-in flex/bison find packages. #977 (1.11.0)
  • Verified that OSL can be built with Clang 8 and LLVM 8.0.
  • When building against recent OIIO versions whose Sysutil supports stack dumps, crashes in the command line tools (including testshade) will print stack traces to aid debugging. #1019 (1.11.0)
  • Improve finding of OpenEXR/IlmBase. #1022 (1.11.0)
  • Fix problems when building against Qt 5.13 due to deprecated calls. #1043 (1.11.0)
  • Fixes for CI when using OIIO 2.1 master that has changed its own cmake minimum to 3.12. #1065 (1.11.1)
  • Improvement for how the build system figures out which LLVM static libraries are needed. #1070 (1.11.1)
  • Improvements in finding Partio. #1125 (1.11.5)
  • Fixes to support Qt 5.15 (currently, osltoy is the only component that uses Qt). #1204 (1.11.6)
  • Better able to find LLVM when the system installation of LLVM has its llvm-config named llvm-config-64. #1238 (1.11.7.1)
  • Fixes for OIIO 2.2 which has eliminated use of tinyformat in favor of always relying on fmtlib. #1242 (1.11.7.1)
• A new build-time CMake variable OSL_LIBNAME_SUFFIX lets you optionally add a custom suffix to the main libraries that are built. (Use with caution.) #970 (1.11.0)
• Add a build-time option GLIBCXX_USE_CXX11_ABI to force the "new/old string ABI" to something other than the default for your version of gcc. #995 (1.10.5/1.11.0)
• stdosl.h and shaders are now installed in PREFIX/share/OSL/shaders. This should not need any changes to shaders, oslc will know where to find them. The location can be overridden by build-time option OSL_SHADER_INSTALL_DIR. #956 (1.10.0)
• When OptiX mode is enabled (USE_OPTIX=1), the testsuite will some tests in an additional time forcing OptiX mode: any test containing a file named OPTIX in its test directory; or all tests if environment variable TESTSUITE_OPTIX=1 (except tests that contain a file named NOOPTIX in their directory. #1004 (1.10.0)
• Allow OSL to build with USE_LLVM_BITCODE enabled on Windows. #998 (1.10.0)
• Various Windows compilation improvements. #1017 #1020
• Fix signed/unsigned comparison warnings. #1037 (1.11.0)
• Fixes for MinGW compiler on Windows. #1047 #1048 (1.11.0)
• Scripts and tests utilizing Python have all been visited to make sure they are compatible with both Python 2.x and Python 3.x. #1071 (1.11.1)
• Build: on OSX, better logic about the OIIO plugin must be built as a module or as a shared library. #1078 (1.11.3/1.10.8)
• Removed support for Boost Wave for preprocessing osl input. We now always use clang library components for preprocessing. #1089 (1.11.3)
• Add an optional build-time EXTRA_WARNINGS option (default: OFF) that enables even more picky than usual warnings. Fix many warnings that cropped up during testing, mostly related to unused function paramters. #1106 (1.11.3)
• The testsuite can run in parallel, with a number of threads set by the environment variable CTEST_PARALLEL_LEVEL. #1119 (1.11.4)
• oslconfig.h is now generated by a cmake configure_file step, from oslconfig.h.in. #1141 (1.11.5)
• Use ASWF docker images to speed up many of the CI matrix entries, as well as to exactly test several VFX Platform specs. #1169 (1.11.6)
• Fix typo that botched the version in the .pc pkgconfig file. #1168 (1.11.6)
• CI test against gcc9 and gcc10. #1192 (1.11.6)
• Propagate RTTI compile options to exported cmake config. #1194 (1.11.6)

Documentation:

• Make it clear that the documentation is licensed under the CC-BY-4.0 license.
• testsuite/example-deformer contains an example of using OSL on a collection of points in a manner that you might use to implement a deformer. #1199 (1.11.6)
• testrender now contains a progressive sampler, which might be a good example for others writing renderers. #1202 (1.11.6)
• Fix incorrect descripton in spline() regarding the number of spline values required for each interpolation type. #1239 (1.11.7.1)

Release 1.10.13 -- 1 Aug 2020 (compared to 1.10.12)

• Small changes to build cleanly against OIIO 2.2.
• Fixes to build against fmtlib 7.0. #1156 #1219
• Docs fixes related to matrix constructors with coordinate systems names.

Release 1.10.12 -- 1 Jul 2020 (compared to 1.10.11)

• Fix bug in regex_search and regex_match where the optimizer could misunderstand which parameters were written. #1186
• Fix warnings when building with gcc9 or gcc10.
• Build cleanly against Qt5.15. #1204

Release 1.10.11 -- 1 Jun 2020 (compared to 1.10.10)

• Fixes to support building against LLVM 9 on some distributions. #1171
• When building against LLVM 10, enforce requirement for C++14 with appropriate warning when using C++11. #1135
• Switch to using CMAKE_CXX_STANDARD as the main way to request particular C++ standard versions. (USE_CPP should continue to work, though.)
• Fixes to MINGW compile, and make sure all stream file I/O is UTF-8 safe. #1188

Release 1.10.10 -- 9 May 2020 (compared to 1.10.9)

• Support for building against LLVM 10.0. #1128 #1162 Note that LLVM 10 can only be used if you are building OSL with C++14 or newer.
• Change default of OSL_BUILD_MATERIALX to OFF. This will probably be deprecated entirely for 1.11's (or 2.0's) final release. But in the mean time, we have drifted out of sync with MX, which has their own copies of this now, so we're disabling building of these shaders by default.

Release 1.10.9 -- 1 Feb 2020 (compared to 1.10.8)

• Windows fix for incorrectly interpreting paths to oslc.exe as if they were "escaped" strings -- for example, "c:\path\to\new\oslc" should not be interpreted as "c:\path<tab>o<newline>ewoslc". #1101
• Speed up OSL concat() function. #1103

Release 1.10.8 -- 1 Dec 2019 (compared to 1.10.7)

• Fix dual implementation of division so that the value is consistent with regular division (#1066)
• Python3 safety of tests and scripts. #1071
• Handle escaped string literals (like "\tfoo\n") more correctly. #1073
• Fixes to ensure locale independence. #1075
• Build: on OSX, better logic about the OIIO plugin must be built as a module or as a shared library. #1078
• Remove pointless assertions from the TypeSpec class. #1079

Release 1.10.7 -- Oct 1, 2019 (compared to 1.10.6)

• Adjust for deprecated material in more recent Qt releases. #1043
• Fixes for MinGW compiler. #1047
• Texture "missingalpha" optional parameter generated incorrect code and crashed. #1044
• Fix incorrect optimizations surrounding 'exit()' calls in the middle of certain shader code blocks. #1051
• LLVM 9 / clang 9 compatibility. #1058
• Fixes to Travis CI system to keep up with OIIO master recently upgrading its minimum required CMake. #1065

Release 1.10.6 -- Jul 4, 2019 (compared to 1.10.5)

• Build: Fixes to FindOpenEXR.cmake. #1022
• ShadingSystem: when building a shader group from serialized commands, respect the global lockgeom default. #1032

Release 1.10.5 -- May 1, 2019 (compared to 1.10.4)

• Extend linearstep() and smooth_linearstep() to work with color, point, vector, and normal types (previously restricted to float). #994
• Improve oslc type error detection for variable declarations with init expressions. Note that this may flag some warnings and errors that went undetected before, involving initialization assignments of incompatible types. #991, #993
• Add a build-time option GLIBCXX_USE_CXX11_ABI to force the "new/old string ABI" to something other than the default for your version of gcc. #995

Release 1.10.4 -- Apr 1, 2019 (compared to 1.10.3)

• LPEs: forbid LPE repetitions inside groups. #972
• Build process: build script finding of LLVM is now more robust to certain library configurations of llvm, particularly where everything is bundled in just one libLLVM without a separate libLLVMMCJIT. #976
• oslc: Improve warnings about ill-advised use of the comma operator. #978
• oslc: Fix an assertion/crash when passing initialization-lists as parameters to a function, where the function argument expected was as array. #983
• oslc: Fix an assertion/crash for certain type constructors of structs, where the struct name was not declared. (This is an incorrect shader, but of course should have issued an error, not crashed.) #988
• Note: The experimental OptiX path is not expected to work in this branch! Development has continued in the 'master' branch. If you are interested in testing the OptiX support while it's under development, please do so with the master branch, because fixes and improvements to the OptiX support are not being backported to the 1.10 branch.
• Tested and verified that everything builds and works correctly with Clang 8 and LLVM 8.0.

Release 1.10.3 -- Feb 1, 2019 (compared to 1.10.2)

• oslc: Writing to function parameters not marked as output was only recently properly recognized as an error (it was documented as illegal all along). Now we demote to a warning, treating it as a full error was too disruptive. #944 (1.10.3)
• testshade: Check that no leftover errors are in the TextureSystem or ImageCache at the end of the test (that would indicate that someplace in OSL we are failing to check texture errors). #939 (1.10.3)
• Improve oso output efficiency. #938 (1.10.3)
• oslc: Fix bug related to counting the proper number of values used for array default value initialization. #948 (1.10.3)
• oslc: Slight modification to the formatting of floating point values in the oso file to ensure full precision preservation for float values. #949 (1.10.3)
• oslc: Fix crash when encountering empty-expression for (;;). #951 (1.10.3)
• oslc: Fix bug in code generation of certain while loops that directly tested a variable as a zero/nonzero test, such as:

      i = 3;
      while (i)
          --i;
  

  whereas the following had worked (they should have been identical):

      i = 3;
      while (i != 0)
          --i;
  

  #947 (1.10.3/1.11.0)
• Fix bug in implementation of splineinverse() when computing with Bezier interpolation. #954 (1.10.3)
• Fix bug in implementation of transformc when relyin on OpenColorIO for color transformation math, in cases were derivatives were needed (this is a rare case probably nobody ran into). #960 (1.10.3)
• Improve thread-safety of the OSLCompiler itself, in case an app wants to be compiling several shaders to oso concurrently by different threads. #953 (1.10.3)

Release 1.10 -- Dec 1, 2018 (compared to 1.9)

Dependency and standards changes:

• LLVM 4.0 / 5.0 / 6.0 / 7.0: Support has been removed for LLVM 3.x, added for 6.0 and 7.0.
• OpenImageIO 1.8/2.0+: This release of OSL should build properly against OIIO 1.8 or 2.0. Support has been dropped for OIIO 1.7.

New back-end targets:

• OptiX Work in progress: Experimental back end for NVIDIA OptiX GPU ray tracing toolkit. #861, #877, #902
  • Build with USE_OPTIX=1
  • Requires OptiX 5.1+, Cuda 8.0+, OpenImageIO 1.8.10+, LLVM >= 5.0 with PTX target enabled.
  • New utility testoptix is an example of a simple OptiX renderer that uses OSL for shaders.
  • Work is in progress to support the majority of OSL, but right now it is restricted to a subset. All the basic math, most of the standard library, noise functions, strings (aside from if you create entirely new strings in the middle of a shader), and closures work. The biggest thing not working yet is textures, but those are coming soon.

New tools:

• osltoy : GUI tool for interactive shader editing and pattern visualization (somewhat in the style of Shadertoy. #827, #914, #918, #926 (1.10.0)
• docdeep : This Python script (in src/build-scripts/docdeep.py) is an experimental tool to scrape comments from code and turn them into beautiful Markdeep documentation. (A little like a VERY poor man's Doxygen, but markdeep!) Experimental, caveat emptor. #842 (1.10.0)

OSL Language and oslc compiler:

• In OSL source code, we now encourage the use of the generic "shader" type for all shaders, and it is no longer necessary or encouraged to mark the OSL shader with a specific type, "surface", "displacement", etc. From a source code and/or oslc perspective, all shaders are the same generic type. A renderer may, however, have different "uses" or "contexts" and may additional runtime perform error checking to ensure that the shader group you have supplied for a particular "use" does not do things or access globals that are not allowed for that use. #899

• C++11 style Initializer lists. (#838) This lets you have constructs like

    // pass a {} list as a triple, matrix, or struct
    void func (point p);
    func ({x, y, z});
  
    // Assign {} to a struct if the types match up
    struct vec2 { float x, y; };
    vec2 v = {a,b};
  
    // Compact 'return' notation, it knows to construct the return type
    vec2 func (float a, float b)
    {
        return {a, b};
    }
  

• osl now warns when it detects duplicate declarations of functions with the exact same argument list, in the same scope. #746

• osl now correctly reports the error when you write to a user-function parameter that was not declared as output (function params are by default read-only, but a shortcoming in oslc has prevented that error from being issued). #878 (1.10.0)

• Fix oslc crash with invalid field selection syntax. #835 (1.10.0/1.9.6)

• oslc fix to properly handle command line arguments if the shader file is not the last argument on the command line. #841 (1.10.0/1.9.7)

• oslc: when using boost.wave for preprocessing, fix whitespace insertion #840 and windows path separators #849. #841 (1.10.0/1.9.7)

• oslc: Fix bug/undefined behavior when trying to format/printf a struct. #849 #841 (1.10.0/1.9.7)

• New rules for how polymorphic function variants are chosen: Matches are now ranked in an objective way that no longer depends on declaration order. Type coercions are preferred in the following order of descending score: exact match, int -> float, float -> triple, spatial triple -> spatial triple, any triple -> triple. If there is a tie for passed arguments, return types will break the tie. If there is still a tie or truly ambiguous case, a warning will be printed explaining the choices and which was chosen. #844 (1.10.0)

• It is now a warning to define the same function twice in the same scope. #853 (1.10.0)

• A shader input parameter marked with metadata [[ int allowconnect = 0 ]] will disallow runtime connections via ConnectShaders(), resulting in an error. #857 (1.10.0)

• oslc command-line argument -Werror will treat all warnings as hard errors (failed compilation). #862 (1.10.0)

• #pragma osl nowarn will suppress any warnings arising from code on the immediately following line of that source file. #864 (1.10.0)

• oslc error reporting is improved, many multi-line syntactic constructs will report errors in a more intuitive, easy-to-understand line number. #867 (1.10.0)

• Faster parsing of very large constant initializer lists for arrays in OSL. We found an inadvertent O(n^2) behavior when parsing initializer lists. It used to be that a constant table in the form an array of 64k floats took over 10s to compile, now it is 50x faster. #901

• Resolution of ambiguous return type functions (such as noise) has been improved when their results are used as arguments to type constructors. #931 (1.10.1)

OSL Standard library:

• There has been a change in the appearance to Cell noise and Gabor noise. This is to fix a bug that made an incorrect pattern for certain negative exact-integer values for cellnoise, and in lots of places for Gabor noise. The only way to fix it was to potentially change the appearance for some shaders. Sorry. If this is a real problem, let us know, perhaps we can make a build-time switch that will let you use the old buggy noise? But since this is a "2.0" release, we figured it was as good a time as ever to let it change to the correct results. #912 (1.10.0)

Shaders:

• Contributed shader library changes:
  • mandelbrot.osl: computes Mandelbrot and Julia images. #827 (1.10.0)
• MaterialX support:
  • Improved support for MaterialX 1.36: add sin, cos, tan, atan2, ceil, sqrt, exp, determinant, ln, transpose, sign, rotate, transforms, rgb/hsv convert, extract, separate, tiledimage. Rename exponent -> power, pack -> combine, hsvadjust -> hueshift. Add some color2/4 mutual conversion operators. Fixes to ramp4, clean up texture mapping nodes, fixes to triplanarprojection weighting. Extend add/sub/mul/div to include matrices. #903, #904, #905, #907, #909 (1.9.10/1.10.0)

API changes, new options, new ShadingSystem features (for renderer writers):

• ShadingSystem API:
  • It is now permitted to ConnectShaders a single component of a color/point/vector/normal to a float and vice versa. #801 (1.10.0)
  • An older version of ShadingSystem::execute, which had been marked as deprecated since OSL 1.6, has been fully removed. #832 (1.10.0)
  • ShadingSystem::Shader() now has all three parameters required (none are optional), though the "use" parameter no longer has any meaning. (It will be deprecated and removed in a future release.) #899
  • ShadingSystem::optimize_group() now takes an optional pointer to a ShadingContext, which it will use if needed (if passed NULL, one will be internally allocated, used, and freed, as before). #936
• ShadingSystem attributes:
  • New "allow_shader_replacement" (int) attribute, when nonzero, allows shaders to be specified more than once, replacing their former definitions. The default, 0, considers that an error, as it always has. #816 (1.10.0).
  • New developer option "llvm_output_bitcode" dumps the bitcode for each group, even if other debug options aren't turned on, and also any dumped bitcode will save as text as well as binary. #831 (1.10.0)
  • New attribute "error_repeats", if set to non-zero, turns off the suppression of multiple identical errors and warnings. Setting it (even to its existing value) also clears the "already seen" lists. #880, #883 (1.10.0/1.9.9/1.8.14)
• Shader group attributes:
  • New attributes that can be queried with getattribute(): "globals_read" and "globals_write" retrieve an integer bitfield that can reveal which "globals" may be read or written by the shader group. The meaning of the bits is given by the enum class SGBits in oslexec.h. #899
• RendererServices API:
  • Older versions of RendererServices texture functions, the old ones with no errormessage parameter, which were documented as deprecated since 1.8, are now marked OSL_DEPRECATED. #832 (1.10.0)
• OSLCompiler API:
  • Improved error reporting when compiling from memory buffer. The OSLCompiler::compile_buffer() method now takes an optional filename parameter that will make error messages attribute the right "file" (e.g., Error: foo.osl:5... rather than <buffer>:5...). #937 (1.10.2)
• Miscellaneous:
  • liboslnoise: Properly hide/export symbols. #849 (1.10.0/1.9.7)
  • The behavior of the "searchpath:shader" attribute, used for finding .oso files when shaders is requested, has been modified. If no search path is specified, the current working directory (".") will be searched. But if there is a search path attribute specified, only those directories will be searched, with "." only searched if it is explicitly included in the search path value. #925 (1.10.0)

Bug fixes and other improvements (internals):

• The context's texture_thread_info is now properly passed to the RenderServices callbacks instead of passing NULL. (1.10.0)
• Symbols are enabled in the JIT, allowing Intel Vtune profiler to correctly report which JITed OSL code is being executed. #830 (1.10.0)
• ASTNode and OSLCompilerImpl -- add info() and message() methods to complement the existing error and warning. #854 (1.10.0)
• Fix incorrect array length on unbounded arrays specified by relaxed parameter type checking. #900 (1.9.10/1.10.0)
• oslc bug fix: the regex_search()/regex_match() functions did not properly mark their results output parameter as write-only. This was never noticed by anyone, but could have resulted in incorrect optimizations. #922 (1.10.0)
• When reading .oso files, the parser is now more robust for certain ways that the oso file might be corrupted (it's more forgiving, fewer possible ways for it to abort or assert). #923 (1.10.0)
• Bug fixes related to incorrect reliance on OIIO's ustring::operator int(). It's being removed from OIIO, so wean ourselves off it. #929 (1.10.0)
• Certain texture3d lookups with derivatives could crash. #932 (1.10.1)
• Fix oslc assertion crash when a struct parameter was initialized with a function call. #934 (1.10.1)

Build & test system improvements:

• Appveyor CI testing for Windows. #849,852,855 (1.10.0/1.9.7)
• Our new policy is to disable STOP_ON_WARNING for release branches, to minimize build breaks for users when a new compiler warning is hit. We still enable it in development/master branches as well as any CI build in any branch. #850 (1.10.0/1.9.7)
• Testsuite is now Python 2/3 agnostic. #873 (1.10.0)
• Build the version into the shared library .so names. #876 (1.8.13/1.9.8/1.10.0)
• Update to fix with OpenImageIO 1.9. #882,#889
• Flex/bison fixes on Windows. #891
• Fix Windows build break with iso646.h macros. #892
• Fix warnings on gcc 6. #896
• Fix errors building with MSVC. #898
• Fixes to build with clang 7, and to use LLVM 7. #910, #921 (1.10.0)
• Fix warnings on gcc 8. #921 (1.10.0)
• Build system: the variables containing hints for where to find IlmBase and OpenEXR have been changed to ILMBASE_ROOT_DIR and OPENEXR_ROOT_DIR (no longer ILMBASE_HOME/OPENEXR_HOME). Similarly, OPENIMAGEIO_ROOT_DIR is the hint for custom OIIO location (no longer OPENIMAGEIOHOME). #928
• Eliminated some in-progress MaterialX tests, they weren't in good order, we will do it differently if we want to add MX tests in the future. #928
• Build options OSL_BUILD_SHADERS and OSL_BUILD_MATERIALX (both default to ON) can be used to disable building of all shaders or MX shaders, respectively. #935 (1.10.1)

Documentation:

• osltoy documentations in doc/osltoy.md.html (1.10.0).

Release 1.9.13 -- 1 Dec 2018 (compared to 1.9.12)

• Fix crash with texture3d lookups with derivatives. #932
• Fix oslc crash when a struct parameter is initialized with a function call that returns a structure. #934

Release 1.9.12 -- 1 Nov 2018 (compared to 1.9.11)

• Fix oslc read/write error for regex_search/regex_match #922
• Make oso reading more robust to certain broken inputs. #923
• Internals: make safe for some changes coming to ustring API in OIIO master. #929
• Several docs fixes.

Release 1.9.11 -- 1 Oct 2018 (compared to 1.9.10)

• Full support for using LLVM 6.0 and 7.0. #913, #919
• Support for building with gcc 8. #921
• Fix testrender bug with undefined order of operations (only was a problem with gcc5 and clang7). #916

Release 1.9.10 -- 1 Sep 2018 (compared to 1.9.9)

• Fix Windows compile of the flex/bison compiler components. #891
• Fix for compatibility with OIIO 1.9.
• Fix incorrect array length on unbounded arrays specified by relaxed parameter type checking. #900
• Speed up oslc parsing of long constant initializer lists. #901
• Add more functions to color2.h, color4.h, vector2.h, vector4.h: ceil, sqrt, exp, log2, log, sign, sin, cos, tan, asin, acos, atan2. #903, #904
• Improved support for MaterialX 1.36: add sin, cos, tan, atan2, ceil, sqrt, exp, determinant, ln, transpose, sign, rotate, transforms, rgb/hsv convert, extract, separate, tiledimage. Rename exponent -> power, pack -> combine, hsvadjust -> hueshift. Add some color2/4 mutual conversion operators. Fixes to ramp4, clean up texture mapping nodes, fixes to triplanarprojection weighting. Extend add/sub/muldiv to include matrices. #903, #904, #905

Release 1.9.9 -- 1 May 2018 (compared to 1.9.8)

• New SS attribute "error_repeats", if set to non-zero, turns off the suppression of multiple identical errors and warnings. Setting it (even to its existing value) also clears the "already seen" lists. #880 (1.8.14/1.9.9)
• Update to fix with some changes in OpenImageIO 1.9. #882

Release 1.9.8 -- 1 Apr 2018 (compared to 1.9.7)

• Build the version into the shared library .so names. #876 (1.8.13/1.9.8)

Release 1.9.7 -- 1 Feb 2018 (compared to 1.9.6)

• oslc fix to properly handle command line arguments if the shader file is not the last argument on the command line. #841
• oslc: when using boost.wave for preprocessing, fix whitespace insertion #840 and windows path separators #849.
• oslc: Fix bug/undefined behavior when trying to format/printf a struct. #849
• liboslnoise: Fix symbol export/hiding. #849
• Misc build issue cleanup on Windows. #849
• For release branches, we no longer have builds consider every compiler warning to be an error (except in master or for CI builds).

Release 1.9.6 -- 1 Jan 2018 (compared to 1.9.5)

• Fix oslc crash with invalid field selection syntax. #835
• Certain texture calls were inadvertently not passing in thread data, forcing the texture system to look it up again redundantly. #829

Release 1.9 -- 4 December 2017 (compared to 1.8)

Dependency and standards changes:

• C++11 required: OSL 1.9 requires a minimum standard of C++11. It should also build against C++14 and C++17.
• LLVM 3.5 / 3.9 / 4.0 / 5.0: Support has been added for LLVM 3.9, 4.0, and 5.0. Support has been removed for for LLVM 3.4.
• OpenImageIO 1.7+: This release of OSL should build properly against OIIO 1.7 or newer. You may find that 1.6 is still ok, but we are not doing any work to ensure that.
• CMake >= 3.2.2
• Boost >= 1.55
• OpenEXR/IlmBase >= 2.0 (recommended: 2.2)

Language features:

• New preprocessor symbols: OSL_VERSION_MAJOR, OSL_VERSION_MINOR, OSL_VERSION_PATCH, and OSL_VERSION (e.g. 10900 for 1.9.0) reveal the OSL release at shader compile time. #747 (1.9.0)

• Structure constructors: If you have a struct S comprising fields with types T1, T2, ..., you may now have an expression S(T1 v2, T2 v2,...) that constructs and returns an S with those field values, much in the same way that you can say color(a,b,c) to construct a color out of components a, b, c. #751 (1.9.0)

• User-defined operator overloading: If you make a new (struct) type, it is possible to define overloaded operators, like this:

  struct vec2 { float x; float y; };
  
  vec2 __operator__add__ (vec2 a, vec2 b) { return vec2(a.x+b.x, ay+b.y); }
  
  vec2 a, b, c;
  a = b + c;   // chooses __operator__add__()
  

  This can be done with any of the operators, see the OSL Language Spec PDF for details. #753 (1.9.0)

Standard library additions/changes:

• getattribute ("osl:version", intvar) at runtime can reveal the OSL version on which the shader is being executed. #747 (1.9.0)
• pointcloud_search()/pointcloud_get() have more flexibility in what type of data it may retrieve: you can now retrieve arrays, if that is what is stored per-point in the point cloud (for example, a float[4]). #752 (1.9.0)
• smoothstep() has been extended to T smoothstep(T edge0, T edge1, T x) for T of any the triple types (previously, smoothstep only came in the float variety). #765 (1.9.0/1.8.10)
• mix() has been extended to support color closure mix (color closure A, color closure B, color x) #766 (1.9.0/1.8.10)
• hashnoise() is like cellnoise (1D, 2D, 3D, or 4D input, 1D or 4D output on [0,1]), but is discontinuous everywhere (versus cellnoise, which is constant within each unit cube and discontinuous at at integer coordinates). #775 (1.9.0/1.8.10)
• int hash (...) has been extended to take arguments that are int, float, 2 floats, point, or point+float. #775 (1.9.0/1.8.10)
• transformc() can now perform any color transformations understood by OpenColorIO (assuming OCIO support was enabled when OSL was build, and that a valid OCIO configuration is found at runtime). #796 (1.9.1) Also, transformc() now fully supports derivatives in all cases. #798 (1.9.1)

Contributed shader library changes:

• New headers: color2.h, color4.h, vector2.h, vector4.h. Technically these are not part of the OSL specification and standard library, but are "contributed" code that you may find handy. They implement 2- and 4- component colors (RA and RGBA) and 2D and 4D vectors. #777 (1.9.1)
• A full complement of MaterialX shaders is now included in the OSL distribution. #777 (1.9.1)

API changes, new options, new ShadingSystem features (for renderer writers):

• ShadingSystem API changes:
  • New set_raytypes() call sets the known raytypes (on and off) for a shader group for subsequent optimization. This lets you combine ray specialization with lazy compilation. #733 (1.9.0)
  • Parameter() is now less strict about type checking when setting parameter instance values. In particular, it's now ok to pass a float value to a "triple" (color, point, etc.) parameter, and to pass one kind of triple when a different kind of triple was the declared parameter type. In this respect, the rules now more closely resample what we always allowed for ConnectShaders. #750 (1.9.0)
  • More optional Parameter() type checking relaxation: if the ShadingSystem attribute "relaxed_param_typecheck" is nonzero, an array of floats may be passed for float aggregates (e.g. color) or arrays of float aggregates, as long as the total number of floats matches. For example, with this attribute turned on, a float[3] may be passed as a parameter that expected a vector. Also, an int may be passed to a float parameter, and an int[1] may be passed to an int parameter. #794,#797 (1.9.1)
  • A new, optional, slightly relaxed policy for type checking what is passed via Parameter()
  • Shader() will now accept the name of the shader as if it were the filename, with trailing .oso, and it will be automatically stripped off. #741 (1.9.0)
  • convert_value() now allows conversions between float[3] and triple values. #754 (1.9.0)
• ShadingSystem attribute additions/changes:
  • "relaxed_param_typecheck" (default=0) enables more relaxed type checking of Parameter() calls: arrays of float may be passed to parameters expecting a float-aggregate or array thereof, and an int may be passed to a parameter expecting a float, and an int[1] may be passed to an int parameter. #794,#797 (1.9.1)
• Fixed ClosureComponent to work with SSE alignment requirements. #810 (1.9.3)

Performance improvements:

• Shader JIT time is improved by about 10% as a result of pre-declaring certain function addresses instead of relying on LLVM to use dlsym() calls to find them within the executable. #732 (1.9.0)
• The runtime cost of range checking array accesses has been reduced by about 50%. #739 (1.9.0)
• Runtime optimization: Constant folding of % operation. #787 (1.9.1)

Bug fixes and other improvements (internals):

• Avoid division by 0 when computing derivatives in pointcloud_search. #710 (1.9.0/1.8.7)
• Avoid subtle use-after-free memory error in dictionary_find(). #718 (1.9.0/1.8.6)
• Fix minor inconsistency in the behavior of normalize() when the input has derivatives versus when it does not. #720 (1.9.0/1.8.7)
• Fix an optimization bug where calls to trace() could accidentally get elided if the results of the function call were unused in the shader. This is incorrect! Because trace() has side effects upon subsequent calls to getmessage("trace",...). #722 (1.9.0/1.8.7)
• Runtime optimizer is sped up by avoiding some string operations related to searching for render outputs when none are registered. (1.9.0)
• Searching for stdosl.h now works uniformly whether it's oslc itself, or apps that use OSLCompiler, and in all cases are better about guessing where the header is located even when $OSLHOME environment variable is not set. #737 (1.9.0)
• Internals: Fix the handling of alignment for closure structs. #740 (1.9.0)
• oslc: fix internal memory leak of ASTNode's. #743 (1.9.0)
• testshade improvements:
  • New option --texoptions lets you directly set extra TextureSystem options for tests. #744 (1.9.0)
  • Fix that allows you to set a parameters that is an array-of-strings. #745 (1.9.0)
  • Rename --scalest/--offsetst to --scaleuv/--offsetuv to properly reflect that they alter u and v (there is no s, t). #757 (1.9.0)
  • --print prints the value of all saved outputs. #757 (1.9.0)
  • Automatically convert to sRGB when saving outputs to JPEG, PNG, or GIF images, to make them more "web ready." #757 (1.9.0)
  • --runstats is more careful about not including the time to write output images in the main shader run time statistic. #757 (1.9.0)
  • Rename -od option to -d to match oiiotool and maketx. #757 (1.9.0)
• testrender: Automatically convert to sRGB when saving outputs to JPEG, PNG, or GIF images, to make them more "web ready." #757 (1.9.0)
• Slight efficiency improvement when you call texture functions with the optional "subimage" parameter and pass the empty string (which means the first subimage, equivalent to not passing "subimage" at all). #749 (1.9.0)
• oslc bug fixes where in some circumstances polymorphic overloaded functions or operators could not be properly distinguished if their parameters were differing struct types. #755 (1.9.0)
• Fix minor numerical precision problems with inversespline(). #772 (1.9.0)
• testshade gives better error messages for the common mistake of using -param after the shader is set up. #773 (1.9.0)
• Fix bug with transitive assignment for arrays, like a[0] = a[1] = 0; #774 (1.9.0)
• The standard OSL library function fprintf() was not properly implemented. #780 (1.9.1)
• Fix subtle bugs related to our ignorance of "locales" -- we now are very careful when parsing .osl source (and other places) to be always use the '.' (dot) character as decimal separator in floating point number, even when running on a computer system configured to use a foreign locale where the comma is traditionally used as the decimal separator. #795 (1.9.1)
• Fix param analysis bug for texture or pointcloud functions with optional token/value parameters where the token name wasn't a string literal -- it could fail to recognize that certain parameters would be written to by the call. #812 (1.9.3)
• ShadingSystem statistics are now printed if any shaders were declared/loaded, even if no shaders were executed. #815 (1.9.3)
• Minor OSLQuery implementation improvements: add move/copy constructors for OSLQuery::Parameter, make the ShadingSystem side of OSLQuery correctly report default parameter values. #821 (1.9.4)

Build & test system improvements:

• C++11 is the new language baseline. #704, #707
• Many uses of Boost have been switched to use C++11 features, including prior uses of boost::shared_ptr, bind, ref, unordered_map, unordered_set now using the std:: equivalents; BOOST_FOREACH -> C++11 "range for"; Boost string algorithms replaced by OIIO::Strutil functions; Boost filesystem replaced by OIIO::Filesystem functions; Boost scoped_ptr replaced by std::unique_ptr; boost::random replaced by std::random; boost::intrusive_ptr replaced by OIIO::intrusive_ptr; boost thread replaced by std::thread and various OIIO::thread utilities. #707 (1.9.0)
• CMake 3.2.2 or higher is now required. The CMake build scripts have been refactored substantially and cleaned up with this requirement in mind. #705 (1.9.0)
• Boost 1.55 or higher is now required (per VFXPlatform guidelines).
• Big refactor of the CMake scripts for how we find LLVM, now also broken out into a separate FindLLVM.cmake. #711 (1.9.0)
• Remove direct references to tinyformat in lieu of C++11 variadic templates and use of OIIO::Strutil::format. #713 (1.9.0)
• Use std::regex rather than boost::regex any time the former is available. (Note: gcc 4.8 will automatically still fall back to boost, since correct implementation of std::regex did not happen until gcc 4.9.) #714 (1.9.0)
• When available (and with the right compiler version combinations), OSL will rely on Clang library internals to "preprocess" oso input, rather than Boost Wave. This solves problems particularly on OSX and FreeBSD where clang/C++11-compiled OSL was having trouble using Boost Wave if Boost was not compiled in C++11 mode (which is difficult to ensure if you don't control the machine or build boost yourself). #715 (1.8.5/1.9.0) #719 #721 (1.9.0/1.8.7)
• Tweaks to FindOpenImageIO.cmake. (1.9.0)
• Fixed linkage problems where some of our unit test programs were unwisely linking against both liboslcomp and liboslexec (not necessary, and caused problems for certain LLVM components that appeared statically in both). #727 (1.9.0/1.8.7)
• Added an easy way to invoke clang-tidy on all the files. #728
• All internal references to our public headers have been changed to the form #include <OSL/foo.h>, and not "OSL/foo.h" or "foo.h". #728
• The namespace has been changed somewhat, is now only one level deep and contains the version, eliminating version clashes within the same executable. You still refer to namespace "OSL", it's an alias for the real versioned (and potentially customized) one. #732 (1.9.0)
• Symbol visibility is now properly restricted for certain "C" linkage functions needed for availability by the LLVM-generated code. And overall, the HIDE_SYMBOLS build mode is now on by default. #732 (1.9.0)
• More robust finding of external PugiXML headers. (1.9.0)
• Fix ilmbase linker warning with LINKSTATIC on Windows. #768 (1.9.0)
• Fix osl_range_check not found error when USE_LLVM_BITCODE=OFF. #767 (1.9.0)
• Windows fixes where BUILDSTATIC incorrectly set /MT flag. #769 (1.9.0)
• Some preliminary work to make OSL safe to compile with C++17. (1.9.1)
• C++11 modernization: use range-for loops in many places. #785 (1.9.1)
• Make OSL build with clang 5.0 and against LLVM 5.0. #787 (1.9.1)
• Removed support for building against LLVM 3.4. #792 (1.9.1)
• Use GNUInstallDirs to simplify build scripts and more properly conform to widely established standards for layout of installation directory files. #788 (1.9.1)
• Improved proper rebuilding of the LLVM bitcode for llvm_ops.cpp when only certain headers change. #802 (1.9.1)
• Fix gcc7 warnings about signed vs unsigned compares. #807 (1.9.2)
• Simplify the build logic for finding PugiXML and prefer a system install when found, rather than looking to OIIO to supply it. #809 (1.9.2)
• MSVS 2015 x64 compilation fixes. #820 (1.9.4)
• Fix debug compile against OIIO 1.7. #822 (1.9.4)

Developer goodies:

• The dual.h implementation has been completely overhauled. The primary implementation of dual arithmetic is now the template Dual<T,PARTIALS> where PARTIALS lets it specialize on the number of partial derivatives. This lets you use the Dual templates for automatic differentiation of of ordinary 1D functions (e.g., Dual<float,1>) or 3D volumetric computations (e.g., Dual<float,3>). Most of OSL internals use automatic differentiation on 2 dimensions (Dual<float,2> a.k.a. Dual2<float>), but this change makes dual.h a lot more useful outside of OSL. #803 (1.9.1)

Documentation:

• Fixed unclear explanation about structures with nested arrays. (1.9.0)
• Full testshade docs in doc/testshade.md.html (1.9.0)

Release 1.8.15 -- 1 Aug 2018 (compared to 1.8.14)

• Fixes for compatibility with OIIO 1.9.

Release 1.8.14 -- 1 May 2018 (compared to 1.8.13)

• New SS attribute "error_repeats", if set to non-zero, turns off the suppression of multiple identical errors and warnings. Setting it (even to its existing value) also clears the "already seen" lists. #880
• Update to fix with some changes in OpenImageIO 1.9. #882

Release 1.8.13 -- 1 Apr 2018 (compared to 1.8.12)

• Build the version into the shared library .so names. #876

Release 1.8.12 -- 1 Nov 2017 (compared to 1.8.11)

• Improve type checking error messages with structs. #761

Release 1.8.11 -- 3 Oct 2017 (compared to 1.8.10)

• Builds properly against LLVM 5.0, and if compiled by clang 5.0.
• Changes to test/CI with recent OIIO release.

Release 1.8.10 -- 1 Jul 2017 (compared to 1.8.9)

• Missing faceforward() implementation was added to stdosl.h. #759
• testshade new option --shader <shadername> <layername> is a convenience that takes the place of a separate --layer and --shader arguments, and makes the command line look more similar to the serialized (text) description of a shader group. #763
• README.md, CHANGES.md, and INSTALL.md are now installed in the "doc" directory of a fully-built dist area, rather than at its top level.
• smoothstep() now has variants where the arguments and return type may be color, vector, etc. (previously it only worked for float. #765
• mix() now has a variant that combines closures. #766
• testshade comprehensive documentation in doc/testshade.md.html, just view with your browser.
• Fixed a numerical precision problem with inversespline(). #772
• Fixed a bug in transitive assignment of indexed arrays, like f[0] = f[1] = f[2]. This previously hit an assertion. #774
• New standard OSL function hash() makes a repeatable integer hash of a float, 2 floats, a triple, or triple + float. #775
• New hashnoise() is similar to cellnoise(), but has a different repeatable 0.0-1.0 range value for every input position (whereas cellnoise is constant between integer coordinates). #775

Release 1.8.9 -- 1 Jun 2017 (compared to 1.8.8)

• Minor speedup when passing blank subimage name: texture (..., "subimage", "", ...) #749
• Fix namespace clash after recent OIIO (master branch) PugiXML version upgrade.
• Several testshade changes: renamed options --scalest/--offsetst to --scaleuv/--offsetuv to more closely say what they really do; rename -od to -d to match how oiiotool and maketx call the same option; automatically convert to sRGB when instructed to save an output image as JPEG, GIF, or PNG; -runstats is more careful with timing to not include image output in shader run time; new --print option prints outputs to console (don't use with large images!). #757

Release 1.8.8 -- 1 May 2017 (compared to 1.8.7)

• New ShadingSystem::set_raytypes() can be used to configure default ray types for subsequent lazy optimization of the group upon first execution. #733
• Hide symbol visibility for extern "C" linkage osl_* functions that LLVM needs. #732
• New oslc-time macros OSL_VERSION, OSL_VERSION_MAJOR, OSL_VERSION_MINOR, OSL_VERSION_PATCH lets you easily test OSL version while compiling your shader. You can also find out at runtime with getattribute("osl:version"). #747

Release 1.8.7 -- 1 Apr 2017 (compared to 1.8.6)

• Fix possible division-by-zero when computing derivatives in pointcloud_search. #710
• When using clang components as the C preprocessor for .osl files, better reporting of any C preprocessor errors. #719
• Fix minor inconsistency in the behavior of normalize() when the input has derivatives versus when it does not. #720
• Fixes to using clang for the C preprocessing -- we discovered cases where it's unreliable for older clang versions, so it now only works when using LLVM >= 3.9 (for older LLVM versions, we fall back to boost wave for our preprocessing needs). #721
• Fix an optimization bug where calls to trace() could accidentally get elided if the results of the function call were unused in the shader. This is incorrect! Because trace() has side effects upon subsequent calls to getmessage("trace",...). #722
• Fixed linkage problems where some of our unit test programs were unwisely linking against both liboslcomp and liboslexec (not necessary, and caused problems for certain LLVM components that appeared statically in both). #727

Release 1.8 [1.8.6] -- 1 Mar 2017 (compared to 1.7)

Dependency and standards changes:

• OSL now builds properly against LLVM 3.9 and 4.0 (in addition to 3.5 and 3.4). Please note that for 3.9 or 4.0 (which use MCJIT), the JIT overhead time is about twice as much as when using LLVM 3.4/3.5 ("old" JIT), but the resulting code runs a bit faster. You may see fast, low-quality, interactive renders slow down, but long complex renders speed up. We are working to address the JIT overhead. In the mean time, if you are especially sensitive to interactive compile speed, just keep using LLVM 3.5 (or 3.4) while we work to address the problem. OSL 1.8 will be the last branch that supports LLVM 3.4 and 3.5.
• C++ standard: OSL 1.8 should build againt C++03, C++11, or C++14. OSL 1.8 is the last release that will build against C++03. Future major releases will require C++11 as a minimum.
• OpenImageIO: This release of OSL should build properly against OIIO 1.6 or newer (although 1.7 is the current release and therefore recommended).

New library: liboslnoise and header oslnoise.h expose OSL's noise functions to C++ apps. Currently, only signed and unsigned perlin, and cellnoise, are exposed, but other varieties and options may be added if desired. #669 (1.8.2)

Language features:

• Function return values are now allowed to be structs. (#636)
• oslc now will warn when assigning the result of a "comma operator", which almost always is a programming error where the shader writer omitted the type name when attempting to construct a vector or matrix. (#635) (1.8.0/1.7.3)
• Nested structs (structs containing other structs) are now functional as shader parameters, with initialization working as expected with nested { {...}, {...} }. #640 (1.8.0)
• oslc (and liboslcomp) now supports UTF-8 filenames, including on Windows. #643 (1.8.0)
• osl now accepts hexadecimal integer constants (such as 0x01ff). #653 (1.8.1)

Standard library additions/changes:

• pow(triple,triple) is now part of the standard library. (1.8.2)
• New getattribute() tokens: "shader:shadername", "shader:layername", and "shader:groupname" lets the shader retrieve the shader, layer, and group names. This is intended primarily for helpful error messages generated by the shader. #673 (1.8.2)
• The texture(), texture3d(), and environment() functions now accept an optional "errormessage" parameter (followed by a string variable reference). A failure in the texture lookup will result in an error message being placed in this variable, but will not have any error message passed to the renderer (leaving error handling and reporting entirely up to the shader). #686 (1.8.2)
• select(a,b,cond) is similar to mix, but without interpolation -- if cond is 0, returns a, else return b (per component). #696 (1.8.3)

API changes, new options, new ShadingSystem features (for renderer writers):

• ShadingSystem API changes:
  • Long-deprecated ShadingAttribState type has been removed (now called ShaderGroup).
  • ShadingSystem::create() and destroy() are no longer necessary and have been removed.
  • A new Shadingsystem::optimize_group() method takes bit fields describing which ray types are known to be true or false, allowing specialized versions of the shader to be optimized for certain ray types (such as for shadow rays only, or displacement shades only). #668 (1.8.2)
• ShadingSystem attribute additions/changes:
  • Attribute "userdata_isconnected", if set to a nonzero integer, causes a shader call to isconnected(param) to return 1 if the parameter is potentially connected to userdata (that is, if lockgeom=0 for that parameter). This if for particular renderer needs, and the default remains for isconnected() to return 1 only if there is an actual connection. #629 (1.8.0/1.7.3)
  • Attribute "no_noise" will replace all noise calls with an inexpensive function that returns 0 (for signed noise) or 0.5 (for unsigned noise). This can be helpful in understanding how much render time is due to noise calls. #642 (1.8.0)
  • Attribute "no_pointcloud" will short-circuit all pointcloud lookups. This can be helpful in understanding how much render time is due to pointcloud queries. #642 (1.8.0)
  • When the attribute "profile" is set, the statistics report will include a count of the total number of noise calls. #642 (1.8.0)
  • ShadingSystem and shader group attribute "exec_repeat" (int; default is
    1. can artificially manipulate how many times the shader is executed. This can sometimes be handy for tricky benchmarks. #659 (1.8.2)
  • Attribute "force_derivs" can force derivatives to be computed everywhere. (Mostly good for debugging or benchmarking derivatives, not intended for users.) #667 (1.8.2)
  • Attribute "llvm_debug_ops" adds a printf before running each op. This is mostly for debugging OSL itself, not for users. (1.8.3)

Performance improvements:

• New runtime optimization: better at understanding the initial values of output parameters and what optimizations can be done based on that. #657 (1.8.1)
• Better runtime optimization of certain matrix constructors. #676 (1.8.2)
• Improved alias analysis for parameters with simple initialization ops. #679 (1.8.2)
• Runtime optimizer now constant-folds bitwise &, |, ^, ~ operators. #682 (1.8.2)
• Improved runtime constant folding of triple(space,const,const,const) when the space name is known to be equivalent to "common". #685 (1.8.2)

Bug fixes and other improvements:

• oslc bug: getmatrix() failed to note that the matrix argument was written. #618 (1.8.0/1.7.2)
• Fix oslc incorrectly emitting init ops for constructor color(float). #637 (1.8.0/1.7.3)
• Fix subtle bug in runtime optimizer that could seg fault. #651 (1.8.0)
• Fixed incorrect instance merging when unspecified-length arrays differed. #656 (1.8.1/1.7.4)
• Fix oslc crash/assertion when indexing into a closure type. #663
• A version of spline() where the knots were colors without derivs and the abscissa was a float with derivs, computed its result derivatives incorrectly. #666
• Fix incorrect dropping of certain optional texture() arguments. #671 (1.8.2/1.7.5)
• Fix: matrix parameters initialized with matrix(space,1) did not initialize properly. #675 (1.8.2/1.7.5)
• Bug fix: matrix parameters initialized with matrix(space,1) did not initialize properly. #675 (1.8.2/1.7.5)
• oslc: better error reporting for use of non-function symbol as a function. #684 (1.8.2/1.7.5)

Build & test system improvements and developer goodies:

• Default build is now C++11! Currently, the project will still build as C++03, but to do so you must explicitly 'make USE_CPP11=0'. #615 (1.8.0)
• Build: better handling of multiple USE_SIMD options. #617 (1.8.0/1.7.2)
• CMake FindOpenEXR.cmake totally rewritten, much simpler and better. #621 (1.8.0/1.7.2)
• 'make CODECOV=1' on a gcc/clang system will run the testsuite and generate a code coverage report in build/$PLATFORM/cov/index.html #624 (1.8.0)
• Remove support for LLVM 3.2 or 3.3. Now the minimum supported version is LLVM 3.4. #627 (1.8.0)
• Changed the CMake variable OSL_BUILD_CPP11 to simply USE_CPP11 (matching the name used for the Makefile wrapper). #634 (1.8.0)
• Clear up inconsistencies with USE_LIBCPLUSPLUS vs OSL_BUILD_USECPLUSPLUS #639 (1.8.0)
• Windows build improvements: Fixed build breaks #643 (1.8.0); fix problems with lexer #646 (1.8.0/1.7.3).
• Improvements in finding OpenEXR installations. #645 (1.8.0)
• Travis tests now include gcc 6 tests. #647 (1.8.0)
• Fixes for build breaks and warnings for gcc6. #647 (1.8.0/1.7.3)
• Fix build breaks for certain older versions of OIIO.
• Failed to properly propagate the C++ standard flags (e.g. -std=c++11) when turning llvm_ops.cpp into LLVM bitcode. #674 (1.8.2/1.7.5)
• Suppress compile warnings when using clang 3.9. #683 (1.8.2/1.7.5)
• Improve search for Partio. #689 (1.8.3)
• More robust finding of LLVM components. (1.8.3)
• OSL now builds properly with LLVM 3.9 and 4.0. #693 (1.8.3)
• When available (and with the right compiler version combinations), OSL will rely on Clang library internals to "preprocess" oso input, rather than Boost Wave. This solves problems particularly on OSX and FreeBSD where clang/C++11-compiled OSL was having trouble using Boost Wave if Boost was not compiled in C++11 mode (which is difficult to ensure if you don't control the machine or build boost yourself). #715 (1.8.5)

Documentation:

• Various typos fixed.
• Explain rules for connections.
• Explain that getattribute retrieves userdata.
• Document that #once works in shader source code.
• The CHANGES and INSTALL files have been changed from plain text to Markdown.

Release 1.7.5 -- 1 Nov 2016 (compared to 1.7.4)

• Fix oslc crash/assertion when indexing into a closure type. #663
• A version of spline() where the knots were colors without derivs and the abscissa was a float with derivs, computed its result derivatives incorrectly. #666
• Incorrect dropping of certain optional texture arguments. #671
• Bug fix: matrix parameters initialized with matrix(space,1) did not initialize properly. #675
• Suppress warnings when compiling with clang 3.9. #683
• oslc: better error reporting for use of non-function symbol as a function. #684
• Filed to properly propagate the C++ standard flags (e.g. -std=c++11) when turning llvm_ops.cpp into LLVM bitcode. #674

Release 1.7.4 -- 1 Aug 2016 (compared to 1.7.3)

• Bug fix: incorrect instance merging when unspecified-length arrays differed. (#656)
• Make oslc understand hex integer constants (like 0x01fc). #653

Release 1.7.3 -- 1 Jul 2016 (compared to 1.7.2)

• ShadingSystem attribute "userdata_isconnected", if set to a nonzero integer, causes a shader call to isconnected(param) to return 1 if the parameter is potentially connected to userdata (that is, if lockgeom=0 for that parameter). This if for particular renderer needs, and the default remains for isconnected() to return 1 only if there is an actual connection. #629 (1.8.0/1.7.3)
• oslc now will warn when assigning the result of a "comma operator", which almost always is a programming error where the shader writer omitted the type name when attempting to construct a vector or matrix. #635 (1.8.0/1.7.3)
• Fix oslc incorrectly emitting init ops for constructor color(float). #637 (1.8.0/1.7.3)
• Bug fix: don't test or set the "layer ran bits" on the last layer of the group. #626 (1.8.0/1.7.3)
• Windows fixes: build breaks #643; fixes for lexer #646.
• Fixes for clean compile with gcc 6.x. #647

Release 1.7.2 -- 1 Mar 2016 (compared to 1.7.1)

• Build: better handling of multiple USE_SIMD options. #617
• oslc bug: getmatrix() failed to note that the matrix argument was written. #618
• CMake FindOpenEXR.cmake totally rewritten, much simpler and better. #621

Release 1.7 [1.7.1] -- 29 Jan 2016 (compared to 1.6)

Language, standard library, and compiler changes (for shader writers):

• Language features:
  • Support for closure arrays in shader inputs. #544 (1.7.0)
  • Disallow quote strings from spanning lines (just like you can't in C). This was never intended, but was accidentally allowed by the oslc lexer. #613 (1.7.1)
• Standard library additions/changes:
  • linearstep() and smooth_linearstep() functions. #566 (1.7.0)
  • isconstant(expr) returns 1 if the expression can be turned into a constant at runtime (with full knowledge of the shader group's parameter values and connections). This is helpful mostly for advanced shader writers to verify their assumptions about which expressions can end up being fully constant-folded by the runtime optimizer. #578 (1.7.1)
  • New behavior of isconnected(parmaname): return 1 if the parameter is connected to an upstream layer, 2 if connected to a downstream layer, 3 if both, 0 of neither. #589 (1.7.1)
  • int hash(string) returns an integer hash of a string. #605 (1.7.1)
  • int getchar(string s,int i) returns the integer character code of the i-th character in string s. #589 (1.7.1)
• Removed from stdosl.h all closure function declarations that were not documented in the spec and not implemented in testrender. (1.7.0)
• osutil.h changes:
  • New draw_string() rasterizes a string! #606 (1.7.1)

API changes, new options, new ShadingSystem features (for renderer writers):

• shade_image() utility runs a shader to generate every pixel of an ImageBuf. (1.7.0)
• ShaingSystem::optimize_group() is a new method that lets you force a shader group to optimize/JIT (without executing it). (1.7.0)
• Remove deprecated ShadingSystem::state() method. #551 (1.7.0)
• Changed logic of lazy shader layer evaluation: "unconnected" layers are now lazy. That means that shaders that appear to have no connected outputs, and don't set globals or set renderer outputs, are no longer run unconditionally. #560 (1.7.0)
• ShadingSystem attribute additions/changes:
  • ShadingSystem attribute "lockgeom" default changed to 1. (1.7.0)
  • SS::getattribute new attributes "num_attributes_needed", "attributes_needed", "attribute_scopes", and "unknown_attributes_needed" can be used to query for a shader group what OSL getattribute queries it might make. #537 (1.7.0)
  • "llvm_debug_layers" controls debug printfs for layer enter/exit (strictly for our debugging of the system; not intended for users). (1.7.0)
  • "opt_passes" controls the number of optimization passes over each instance (default: 10). This is mainly for developer debugging, you should not need to change or expose this. #576 (1.7.1)
  • "connection_error" controls whether a bad connection is considered a true error (or is just ignored). #583 (1.7.1)
• Shader group attribute additions/changes:
  • Group attribute "entry_layers" can explicitly provide a list of which layers within the group (specified by layer names) are "entry points", and then new ShadingSystem methods execute_init(), execute_layer(), and execute_cleanup() can be used to call them individually in any order. The old execute(), which executes starting with the "root" and lazily evaluating any upstream nodes needed, still works and is still the usual way to run shaders for most purposes. #553 (1.7.0)
• RendererServices:
  • Remove has_userdata() method, which was unused. #603 (1.7.1)
• osl.imageio.so -- an OIIO image reader plugin that runs OSL shaders to generate pixels in an image (or texture). #531 (1.7.0)

Performance improvements:

• Much faster (10x or more, for large shaders) parsing of oso files (and .osl source as well). #511 (1.7.0)
• Optimize away unused optional arguments to noise functions. #548 (1.7.0)
• Improved runtime optimization via better tracking of variable aliasing across certain basic block boundaries. #585,588 (1.7.1)

Bug fixes and other improvements:

• oslinfo now has a "--runstats" flag to report how much time it takes to OSLQuery the shaders. (Mostly used for benchmarking the speed of OSLQuery internals.) #510 (1.7.0)
• Improved "debug_uninit" mode eliminates certain false alarms, and when uninitialized values are found, the error messages is more clear about which shader group and layer were involved (in addition to the previous reporting of the OSL source file ane line number). #512 (1.7.0)
• Bug fix serializing shader groups with "unsized arrays." #539 (1.7.0)
• Make sure OSL works fine with LLVM 3.5. #542 (1.7.0)
• Bug fix with unconditional running of earlier layers. (1.7.0)
• Improved error message for range errors and uninitialized variable errors (when using "range_checking" and "debug_uninit", respectively). #540 (1.7.0)
• Fixed oslc bug where shader parameters that were structs and whose values were initialized by copying another struct whole, generated incorrect initialization code. (1.7.0)
• Better tracking of layers that are the unused duplicates after an instance merge. This allows us to be sure those layers are skipped, and avoid situations where they look like they should run unconditionally. #506 (1.7.0)
• Record oslc options in a comment at the start of the oso file. #575 (1.7.1)
• Better error messages when an closure is used that is unknown to the renderer. #576 (1.7.1)
• Fix potential SIGFPE from divide-by-zero in shaders. #596 (1.7.1)
• Improve optimizer logic behind lifetime analysis inside loops, fixing some subtle optimizer bugs. #598 (1.7.1)

Build & test system improvements and developer goodies:

• Allow testshade to test OSL snippets without whole full shaders. #564 (1.7.0)
• Much less verbose builds, when not using VERBOSE=1. (1.7.0)
• New build-time options:
  • USE_NINJA=1 will use Ninja rather than Make (faster!). #546 (1.7.0)
  • USE_fPIC=1 will build with -fPIC. (1.7.0)
  • OSL_BUILD_TESTS=0 will cause it to not build unit tests, testshade, or testrender. (1.7.0)
  • OSL_NO_DEFAULT_TEXTURESYSTEM=1 will cause the ShadingSystem to not create a raw OIIO::TextureSystem, and instead hit an assertion if a TextureSystem is not passed to the ShadingSystem constructor. Use this when building OSL to embed in renderers that supply their own TextureSystem class rather than using OIIO's. (1.7.0)
• Fixes when building for VS2012. #543 (1.7.0)
• Add --path to testshade and testrender to allow setting search path to find oso files. #549 (1.7.0)
• Testsuite: the presence of a file called "OPTIMIZEONLY" in a test directory will cause that test to run only in optimized mode. (1.7.0)
• Better detection of clang version. #559 (1.7.0)
• testshade --offsetst and --scalest let you make custom st ranges for the image being sampled (not restricted to 0-1 defaults). #565 (1.7.0)
• C++11 compatibility. #573 (1.7.1)
• Ensure proper build on Apple Clang 6.1. #580 (1.7.1)
• CMake build option OSL_BUILD_PLUGINS, if set to OFF, will disable building of any OSL plugins (such as the osl.imageio.so). #587 (1.7.1)
• CMake build option OSL_BUILD_TESTS, if set to OFF, will disable building of standalone test programs. #587 (1.7.1)
• We now use Travis-CI to do continuous integration and testing of every checkin and PR for a variety of platform / compiler / option combinations. #592,595,600 (1.7.1)
• Get rid of the "make doxygen" target, which did nothing. (1.7.1)
• Build scripts automatically use ccache if available and in an obvious location. This can be forcefully disabled by setting USE_CCACHE=0. #595,597 (1.7.1)
• Use deprecation attribute for the methods that are considered deprecated. #602,607,608 (1.7.1)
• Testsuite organization overhaul now avoids copying test source to build. #612 (1.7.1)
• New macro OSL_CPLUSPLUS_VERSION (set to 03, 11, 14, etc) rather than using OSL_USING_CPP11. #581 (1.7.1)

Documentation:

Release 1.6 -- 26 May 2015 (compared to 1.5)

Language, standard library, and compiler changes (for shader writers):

• It is now supported to have shader parameters that are arrays of unspecified length (like 'float foo[] = {...}'). Their length will be fixed when they are assigned an instance value of fixed length, or when connected to another layer's output parameter of fixed length. If there is no instance value nor a connection, the length will be fixed to the number of elements given in the default initializer. #481 #497 (1.6.4)
• The "comma operator" now works in the way you would expect in other C-like languages. #451 (1.6.2)
• The "and", "or", and "not" keywords are synonyms for the &&, ||, and ! operators, respectively. (If this seems strange, note that this is true of C++ as well.) #446 (1.6.2)
• oslc will now silently ignore trailing commas in function or shader parameter lists and metadata lists. #447 (1.6.2)
• The "gabor" varieties of noise were found to have a serious mathematical bug, which after fixing results in a change to the pattern. We are hoping that they were rarely used, but beware a change in appearance. (1.6.1)
• We have clarified that shader metadata may be arrays (still not structs or closures) and fixed the implementation to support this (in addition to several other ways that metadata was brittle). (1.6.2)
• Spec clarification: emission() has units of radiance, so a surface directly seen by the camera will directly reproduce the closure weight in the final pixel, regardless of it being a surface or volume. Thus, you don't need to weight it by PI. #427 (1.6.2)
• oslc bug fixed in variable declaration + assignment of nested structs. #453 (1.6.2)

API changes, new options, new ShadingSystem features (for renderer writers):

• New ShadingSystem attribute int "profile", if set to 1, will include in the runtime statistics output a measure of how much total time was spent executing shaders, as well as the identities and times of the 5 shader groups that spent the most time executing. Note that this option is 0 (off) by default, since turning it on can add significantly to total runtime for some scenes. #418 (1.6.2)
• New per-ShaderGroup attributes:
  • You can retrieve information about all closures that an optimized group might create using new queries "num_closures_needed", "closures_needed", "unknown_closures_needed". This could be useful for renderers by, for example, noticing that a material can't possibly call the "transparent" closure, and thus concluding that it must be opaque everywhere and thus shadow rays need not execute shaders to determine opacity. (#400) (1.6.0)
  • You can retrieve information about all "globals" (P, N, etc.) that an optimized group needs using new queries "num_globals_needed" and "globals_needed". This could be useful for renderers for which computing those globals is very expensive; examining which are truly needed and only computing those. (#401) (1.6.0)
• It is now possible to specify per-group "renderer_outputs" in the form "layername.paramname", thus designating a parameter of a specific layer as a render output that should be preserved, but excluding identically named output variables in other layers. #430 (1.6.2)
• New ShadingSystem runtime option int "lazy_userdata", when set to nonzero, causes userdata to be interpolated lazily (on demand) rather than at the beginning of a shader that needs it. For some renderer implementations, this may be a performance improvement. #441 (1.6.2)
• New OSLCompiler::compile_buffer() method compiles OSL source in a string into oso stored in a string. When combined with ShadingSystem:: LoadMemoryCompiledShader, this allows an application to go straight from osl source code to executing shader without writing disk file or launching a shell to invoke oslc. #444 (1.6.2)
• OSLQuery: in the OSLQuery::Parameter structure, the 'validdefault' field now reliably is true for a valid default value, false if no default value could be statically determined (for example, if the param default is the result of code that must run at runtime). (1.6.2)
• Extend ShadingSystem::get_symbol() to retrieve the symbol from a particular named layer (rather than always getting it from the last layer in which the name is found). #458 (1.6.2)
• New SS option "opt_merge_instances_with_userdata", which if set to 0 will prevent instance merging for instances that access userdata. If you don't know why you'd want this turned off, you don't want it turned off! #459 (1.6.2)
• New RendererServices::supports() function allows for future expansion of querying (by the ShadingSystem) of features supported by a particular renderer. #470 (1.6.2)
• New ShadingSystem::execute() variety that takes a ShadingContext* rather than a ShadingContext&. If you pass NULL for the context pointer, the SS will automatically allocate (and eventually release) a context for you. #471 (1.6.2)
• New RendererServices API methods added that supply a handle-based version of texture(), texture3d(), environment(), and get_texture_info(), in addition to the existing name-based versions. Renderer implementations will need to add these, if they overload the name-based ones. #472 (1.6.2)
• RendererServices API methods for texture have been revised again, now each variety takes a filename (will always be passed) and also a TextureHandle* and TexturePerthread* (which may be NULL). Renderers may use the name only if that's easiest, but also may use the handle when supplied. #478 (1.6.3)
• New ShadingSystem methods: find_symbol() and symbol_address() tease apart the functionality of the (now deprecated) get_symbol(). The fairly expensive name lookup is in find_symbol(), and it can be done once per shader group (and reused for the lifetime of the group), while the relatively inexpensive symbol_address() can be cheaply done after each shader execution. If your renderer is currently using get_symbol() to retrieve the shader output values after each shade, we strongly recommend changing to the find_symbol() [once up front] and symbol_address() [once per execution] combination for improved performance. #495 (1.6.4)

Performance improvements:

• Many noise() varieties have been sped up significantly on architectures with SIMD vector instructions (such as SSE). Higher speedups when returning vectors rather than scalars; higher speedups when supplying derivatives as well, higher speedups the higher the dimensionality of the domain. We're seeing 2x-3x improvement for noise(point), depending on the specific variety, 3x-4x speedup for 4D noise varieties. #415 #422 #423 (1.6.1, 1.6.2)
• Change many transcendental functions (sin, cos, exp, etc) to use approximations that are must faster than the 100% correct versions in libm. The new ones may differ from the old in the last decimal place, which is probably undesirable if programming ICBM guidance systems, but seems fine for rendering when the result is many times faster to evaluate those functions. You can turn it back to the fully precise and slow way by building with OSL_FAST_MATH=0. #413 (1.6.0)
• New runtime optimization of mix(a,a,x) -> a (even if none of them are constant). #438 (1.6.2)
• Fix performance regression: avoid incrementing profile-related stats on every execution if profiling is disabled. (1.6.2)
• When the runtime optimizer can figure out which textures are being called, it will retrieve the handle once and generate code for handle-based RendererServices callbacks, rather than name-based ones. This speeds up texture-heavy shading by 5-10% by eliminating the need for the name-to-handle lookups for every texture call. #472 (1.6.2)
• New runtime optimization: constant folding of sincos(). #486 (1.6.4)
• New runtime optimization: constant folding of matrix construction from 16 floats. #486 (1.6.4)
• Improved optimizations -- caught some additional places where assignments could be found to be useless and eliminated. #403 (1.6.4)
• Improved speed of runtime optimization for large shaders. #499 (1.6.5)
• Improved threading performance by not locking during pointcloud_search and pointcloud. (1.6.5)
• Dramatic speedup of runtime optimization of large shaders (5x for big shaders (1.6.5)
• Speed up loading of large shaders from disk (1.6.5).

Bug fixes and other improvements:

• oslinfo --param lets you ask for information on just one parameter of a shader. #397 (1.6.0)
• oslc now properly catches and issues error messages if you define a struct with duplicate field names. #398 (1.6.0)
• Some math speedups (especially those involving sqrt). (1.6.0)
• Improved detection of shader groups that optimize away to nothing. (1.6.2)
• Fix of possible (but never reported) bug with instancing merging. #431 (1.6.2)
• Fix incorrect oslc code generation when assigning an element of an array-of-structs to another element of array-of-structs. #432 (1.6.2)
• Bug fix in code generation of constant folding of getmatrix() calls (never reported symptomatic). #440 (1.6.2)
• Fixes to construction of temporary filename used for group serialization archive. (1.6.2)
• Internals fix: logb() incorrectly declaring derivative functions (it has no derivs). #437 (1.5.12/1.6.2)
• Catch serialization errors resulting from failed system() calls to zip/tar the archive. #436 (1.5.12/1.6.2)
• Bug fix: Delay instance merging from ShaderGroupEnd until optimize time, it messed with the serialization. #426 (1.5.12/1.6.2)
• Fix OSLQuery crash when reading .oso file of a compiled shader that had local variables but no parameters. #435 (1.5.12/1.6.2)
• Shader-wide metadata is now correctly output by oslc, and correctly read by OSLQuery. #455 (1.6.2)
• Only merge instances when optimize level >= 1. #456 (1.6.2)
• Bug fix: runtime optimizer should not consider a layer unused if its outputs are renderer outputs. Also fix subtle bug in detecting whether an output param is a renderer output. #457 (1.6.2)
• Clear derivatives properly in the implementation of gettextureinfo. #463 (1.6.2)
• Correct handling of point-like shader parameters defined with default values that use the constructors that provide "space" names. #465 (1.6.2)
• Fixed some subtle runtime optimizer bugs. #485 #491 (1.6.4)
• Using "debugnan" mode now also checks for NaNs in the results of interpolated userdata. #490 (1.6.4)
• Fixed bug in generating code for closure optional keyword parameters. #492 (1.6.4)
• Fixed bug where instances were incorrectly merged if they had a parameter that was never used in the shader, but was connected downstream, and each of the two instances had a difference instance value for that parameter. #493 (1.6.4)
• Fix critical bug that in very particular circumstances could result in shader layers not executing when they should. (1.6.5)

Under the hood:

• Change a couple long-deprecated OIIO calls to modern versions. #448 (1.5.12/1.6.2)
• Change runtime code generation, putting TextureOptions, NoiseParams, TraceOptions in the ShadingContext, which avoided a dynamic alloca which was tickling an LLVM code generation bug. #442 (1.5.12/1.6.2)
• Allow memory-aligned closure component classes. (1.6.2)
• Lots of internal refactoring of llvm_ops.cpp in order to better and more performantly support MCJIT and newer LLVM releases. #468 (1.6.4)

Build & test system improvements and developer goodies:

• Windows build fix for compiling shaders finding the right oslc.exe. #399 (1.6.0/1.5.11)
• Fix thread contention issue in testshade that was making benchmarks inaccurate. $407 (1.6.0)
• Build scripts better help messages. (1.6.0)
• Changes to build correctly against LLVM 3.5, though please note that using LLVM 3.5 seems to require C++11. If you have C++98 toolchain, then please continue using LLVM 3.4. #412 (1.6.0)
• testrender improvements: update the microfacet models to the latest improved visible normal sampling technique of d'Eon & Heitz, stratified sampling, simplification of Oren-Nayar, and speed improvements. #425 (1.6.2)
• Build fixes for recent OIIO changes. (1.5.12/1.6.2)
• testshade -group now accepts the name of a file containing the serialized group. #439 (1.6.2)
• Various fixes for Windows and Visual Studio 2010. #461 #462 #464 (1.6.2)
• testshade -param can now specify arrays. (1.6.4)
• Remove the USE_MCJIT build flag. Now we ALWAYS compile with ability to use MCJIT any time we are using LLVM that's new enough to have it, and a renderer can select MCJIT at runtime by setting the SS attribute "mcjit" to nonzero (the default, 0, will use old JIT). When compiling against LLVM 3.6 or newer, which has removed MCJIT, OSL will always use MCJIT. #487 #488 (1.6.4)
• Fixes to work with LLVM 3.5 and 3.6, though 3.6 especially has not yet been very thoroughly tested for OSL. #487 (1.6.4)
• C++11 support: the preprocessor symbol OSL_BUILD_CPP11 is set to 1 if OSL was built with C++11 (or higher) support, and the separate OSL_USING_CPP11 is set to 1 if C++11 is detected right now. (These can be different from the point of view of an app using OSL headers.) #508 (1.6.6RC1)

Documentation:

• Short chapter added to spec describing the syntax of our serialization protocol.
• Documentation fix: surfacearea() should return float, not int. (1.5.12)
• Clarified that the way to use gettextureinfo() to retrieve matrices from textures created from rendered images (or shadow maps) is with the tags "worldtocamera" (for the world-to-3D-camera) and "worldtoscreen" (for the world-to-2D-projection that runs -1 to +1 in x and y).
• Clarified documentation on gettxtureinfo(file,"exists"). (1.6.2)
• Improved the comments in shaderglobals.h to explain in detail the meaning and use of all the fields. #489 (1.6.4)

Release 1.5.12 -- 26 Dec 2014 (compared to 1.5.11)

• Build fixes for 32 bit machines.
• Documentation fix: surfacearea() should return float, not int.
• Bug fix: Delay instance merging from ShaderGroupEnd until optimize time, it messed with the serialization.
• Build fixes for recent OIIO changes.
• Fix OSLQuery crash when reading .oso file of a compiled shader that had local variables but no parameters.
• Catch serialization errors resulting from failed system() calls to zip/tar the archive.
• Fix logb() incorrectly declaring derivative functions (it has no derivs).
• Change a couple long-deprecated OIIO calls to modern versions.

Release 1.5.11 -- 22 Sep 2014 (compared to 1.5.10)

• Windows compilations fixes for very MSVC 2013.
• Windows build fix for compiling shaders finding the right oslc.exe. #399
• Speedup from telling gcc/clang to ignore the fact that math functions can set errno (helps code generation of sqrtf in particular.
• Fix thread contention issue in testshade which could make it hard to use testshade as a benchmark with many threads.
• Make it build properly with LLVM 3.5.
• Fix compiler warnings about signed/unsigned comparisons.

Release 1.5 (1.5.10) -- July 30, 2014 (compared to 1.4)

Language, standard libary, and compiler changes (for shader writers):

• New closure function for microfacet BSDFs: closure color microfacet (string distribution, normal N, float alpha, float eta, int refract) closure color microfacet (string distribution, normal N, vector U, float xalpha, float yalpha, float eta, int refract) These replace the growing zoo of microfacet_blah functions (using different distribution values such as "beckmann" or "ggx", as well as selecting refraction when refract!=0). The old varieties are now considered deprecated and will eventually be removed (but will alow back-compatibility of compiled oso files).
• Remove documentation about unimplemented hash() function -- it was never implemented, and we can't figure out what it's good for. (#359) (1.5.7)
• Documented the specific names that should be used with getattribute() to retrieve common camera parameters. We should expect these to be the same for all renderers (though individual renderers may also support additional attribute queries). #393 (1.5.9)

API changes, new options, new ShadingSystem features (for renderer writers):

• ShadingSystem API changes:
  • ShadingSystem::Parameter() has a new variety that can set lockgeom=0 for a particular parameter at runtime, even if it was not declared this way in the shader's metadata. This allows an app to effectively say "I intend to vary this shader's parameter value, don't optimize as if it were a a constant." (1.5.1)
  • New ShadingSystem::ReParameter() lets you change the instance value of a shader parameter after the shader group has already been declared (but only if the shader has not yet been optimized, OR if the parameter was declared with lockgeom=0). This, in combination with the new SS::Parameter() variety, lets an app select a parameter for variation, compile the shader network, and then continuously modify the value and re-render without needing to redeclare and recompile the shader group (though at a slightly higher execution cost than if the parameter were fully optimized. (1.5.1)
  • ShadingAttribState has been simlified and replaced with ShaderGroup. And ShadingAttribStateRef replaced by ShaderGroupRef. (1.5.1)
  • ShaderGroupBegin returns the ShaderGroupRef for the group, there is no need to call state() to get the group reference. (1.5.1)
  • New ShadingSystem::getattribute() and attribute() varieties that takes a ShaderGroup* as a first argument, allows setting and retrieval of attributes pertaining to a specific shader group. (#362, #368) (1.5.8) SEE SECTION BELOW ON GROUP-SPECIFIC ATTRIBUTES
  • New ShaderGroupBegin() variant takes a text description of a shader group. (3.5.8) (#379) For example: ShaderGroupBegin ("groupname", "surface", "param float fin 3.14; " /concatenate string/ "shader a alayer;" "shader b blayer;" "connect alayer.f_out blayer.f_in;");
  • ShadingSystem methods renderer() and texturesys() retrieve the RendererServices and TextureSystem, respectively. (1.5.8)
  • ShadingSystem statistics output now prints the version and major runtime options. (1.5.8) (#369)
• New/changed ShadingSystem global attributes:
  • Attributes "archive_groupname" and "archive_filename", when set, will cause the named group to be fully archived into a .tar, .tar.gz, or .zip file containing the serialized description of the group, and all .oso files needed to reconstruct it. This is great for shipping debugging or performance benchmark cases to the developers! It's also a good way to "extract" a shader network from the midst of a complex renderer and then be able to reconstitute it inside a debugging test harness like testshade. (1.5.8) (#381) For more detail and explanation, please see AcademySoftwareFoundation#381
• New per-ShaderGroup attributes:
  • ShadingSystem::getattribute(group,...) allows queries that retrieve all the names and types of userdata the compiled group may need ("num_userdata", "userdata_names", "userdata_types"), as well as the names of all textures it might access and whether it's possible that it will try to acccess textures whose names are not known without executing the shader ("num_textures_needed", "textures_needed", "unknown_textures_needed"). (#362) (1.5.8)
  • Retrieving the group attribute "pickle" (as a string) gives you the serialized description of the shader group in the same format that is accepted by ShaderGroupBegin(). (1.5.8) (#381)
  • Group-wise attribute "renderer_outputs" (array of strings) lets you specify different renderer outputs for each shader group in addition to the ShadingSystem-wide "renderer_outputs" that apply to all groups. Remember that naming the renderer outputs prevents those from being optimized away if they are not connected to downstream shaders. (1.5.8) (#386)
  • New group attribute queries: "groupname", "num_layers", "layer_names" allow you to ask for the name of the group, how many layers there are, and the names of all the layers.
• ShaderGlobals changes:
  • Added a RendererServices pointer to ShaderGlobals, to eliminate a bunch of pointless indirection during shader execution. (1.5.2)
  • Split the definition of ShaderGlobals into its own header file, shaderglobals.h. (1.5.1)
• RendererServices changes:
  • RendererServices::get_texture_info method parameters have changed, now includes an additional ShaderGlobals* parameter (as did all the other texture functions already). (1.5.5)
  • Split RendererServices definition into separate rendererservices.h. (1.5.6)
  • Add RendererServices::texturesys() that returns a pointer to the RS's TextureSystem. (1.5.6)
  • Add a ShaderGlobals* parameter to the various get_matrix and get_inverse_matrix methods. This makes it easier for renderers that might need the ShaderGlobals (or access to the void* renderstate contained therein) to look up matrices, especially if the renderer supports different per-primitive transformation name bindings. #396 (1.5.10)
  • Change the last 4 RenderServices methods that took a void* renderstate to instead take a ShaderGlobals *. It's more general, since the SG does itself contain the renderstate pointer, and some implementations or features might need the other contents of the SG. #396 (1.5.10)
• OSLQuery changes:
  • OSLQuery::Parameter has a new 'structname' field, that for struct parameters reveals the name of the structure type. The oslinfo utility has also been updated to print this information. (1.5.4)
  • OSLQuery now may be initialized by a ShaderGroup*, which allows an app with a live shading system to query information about shaders much more efficiently than reloading and parsing the .oso file from disk. #387 (1.5.8)
  • OSLQuery API has replaced most of its std::string parameters and members with string_view and ustring, to speed it up and eliminate lots of small allocations. This may introduce some small source incompatibilities with the old OSLQuery, but they should be very easy to fix in your code. #387 (1.5.8)
• Miscellaneous/general:
  • Use OIIO's new string_view for many public API input parameters that previously took a std::string& or a const char*. (1.5.7) (#361)
  • De-virtualized OSLCompiler and ShadingSystem classes -- it is now safe to construct them in the usual way, the create() and destroy() functions for them are optional/deprecated. (#363) (1.5.8)

Performance improvements:

• Dramatically speed up LLVM optimization & JIT of small shaders -- reducing the per-shader-network compile overhead of small shaders from 0.1-0.2s to less than 0.01s per shader group. (1.5.1)
• Runtime constant folding of substr(). (1.5.6)
• Improved code generation for texture calls, removing redundant setting of optional texture parameters when they don't change from the default values. (1.5.6)
• Remove lock from RendererServices texture calls that would create a big thread botteneck (but only for renderers that used the RS base class texture calls; those that overrode them would not notice). (1.5.6)
• Constant folding of certain assignments to individual components or array elements. (#356) (1.5.7)
• Much more complete constant-folding of format(). (1.5.8) (#366)
• Enhanced simplification of component and array assignment, when multiple assignments actually fill out the entire array or aggregate. For example: 'color C; C[0] = 3.14; C[1] = 0; C[2] = 42.0;' Now it recognizes that all components are assigned and will replace the whole thing (and subsequent uses of C) with a constant color. (1.5.8) (#367)
• Eliminate redundant retrieval of userdata within a shading network. (1.5.8) (#373)

Bug fixes:

• testshade/testrender timer didn't properly break out execution time from setup time. (1.4.1/1.5.1)
• Guard matrix*point transformations against possible division by zero. (1.4.1/1.5.1)
• Fix subtle bug with splines taking arrays, where the number of knots passed was less than the full length of the array, and the knots had derivatives -- the derivatives would be looked up from the wrong spot in the array (and could read uninitialized portions of the array). (1.4.1/1.5.3)
• Fix incorrect function declarations for the no-bitcode case (only affected Windows or if a site purposely built without precompiled bitcode for llvm_ops.cpp). (1.4.1/1.5.3)
• When using Boost Wave for oslc's preprocessor, fixed it so that variadic macros work. (1.5.4)
• Ensure that isconnected() works for struct parameters. (1.5.4)
• Fix incorrect data layout in heap for certain array parameters. (1.5.5/1.4.2)
• oslc -D and -U did not work properly when OSL was built against Boost Wave as the C preprocessor. (1.5.5/1.4.2)
• oslc bug fix for innitializing array elements inside a parameter that's a struct. (1.5.6)
• Implementation of the luminance() function has been improved to guarantee that all the components sum to exactly 1.0. (1.5.6)
• OSLQuery: for array parameters whose source code only specify default values for partially initializing the array, nonetheless make the default vectors be the correct length for the array (with zeroes for array elements without explicit initialization). (1.5.6)
• oslc: negating closures resulted in hitting an assertion. (1.5.6)
• ShadingSystem - bug fix when Parameter() sets the same parameter twice for the same instance, the second time back to the default value. (1.5.8) (#370)
• Fix debug printing crash when group name was not set. (1.5.7)
• Bug fix with runtime optimization instance merging -- differing "lockgeom" status of parameters should invalidate the merge. (1.5.8) (#378)
• Runtime optimizer bug fix: output parameter assignment elision was overly aggressive when the output parameter in question was a renderer output (and therefore should not be elided). (1.5.8) (#378)
• Fix printf("%f",whole_float_array) to work properly. (1.5.8) (#382)
• oslc improperly allowed ONE too many initializers for arrays. (1.5.8) (#383)

Under the hood:

• Internals refactor that separates the runtime optimization from the LLVM generation and JIT. (1.5.1)
• Removed legacy built-in closures that weren't actually used. (1.5.1)
• Split all the direct calls to LLVM API into a separate LLVM_Util class, which has no other OSL dependencies and may be used from other apps to simpilfy use of LLVM to JIT code dynamically. (1.5.1)
• Stop using deprecated TypeDesc #defines. (1.5.4)
• A shader's printf, warning, and error output is now buffered so that all the "console" output from a shader invocation will appear contiguous in a log, rather than possibly line-by-line interspersed with the output of another shader invocation running concurrently in a different thread (1.5.5).
• By de-virtualizing OSLCompiler and ShadingSystem classes, we make it much easier in the future to change both these classes (at least, adding new methods) and changing the Impl internals, without breaking link compatibility within release branches. (#363) (1.5.8)
• Eliminate the need for a special dlopen when using OSL from within a DSO/DLL plugin of another app. (1.5.8) (#374, #384)

Build & test system improvements and developer goodies:

• Make OSL work with LLVM 3.4 (1.5.4)
• New llvm_util.h contains an LLVM_Util standalone utility class that can be used from any app as a simplified wrapper for LLVM code generation and JIT. (1.5.1)
• testshade consolidates --iparam, --fparam, --vparam, --sparam into just --param that figures out the types (or could be explicitly told. (1.5.1)
• More robust detection of clang, for older cmake versions. (1.4.1/1.5.1)
• Handle 3-part version numbers for LLVM installations. (1.4.1/1.5.1)
• Fix USE_EXTERNAL_PUGIXML versus USING_OIIO_PUGI issue. (1.4.1/1.5.3)
• Remove all ehader include guards, switch to '#pragma once' (1.5.2)
• Adjust build to account for new library names in OpenEXR 2.1. (1.5.3)
• Make sure we include all OpenEXR and Ilmbase headers with <OpenEXR/foo.h> and remove the addition of OpenEXR sub-folder from system search paths. (1.5.1)
• Better detection of LLVM version number from the LLVM installation. (1.5.1)
• Support for using LLVM's "MCJIT" instead of "old JIT" (controlled by using the optional 'make USE_MCJIT=1'). This is mostly experimental, and not recommended since performance of old JIT is still much better than MCJIT. (1.5.6) Fixes in (1.5.8) (#385)
• Moved the source of all public header files to src/include/OSL, to more closely mimic the install file layout. (1.5.6)
• Fixes for compilation warnings with newer gcc. (1.5.7) (#351)
• Fixes for IlmBase 2.1 build breakages. (#354) (1.5.7)
• Make testshade multithreaded, so it's always exercising the thread safety of the shading system. (1.5.8) (#365)
• Compatibility with cmake 3.0. (1.5.8) (#377)
• Fix warnings with some gcc versions. (1.5.8)
• Make testrender accept the new shadergroup syntax. (1.5.9)
• Make testrender & testshade support all the standard camera getattribute queries. (1.5.9)
• testshade/testrender: have get_attribute fall back on get_userdata, and have get_userdata bind "s" and "t" to make it easy to test shader that rely on userdata. #395 (1.5.10)
• Fixes for Boost 1.55 + Linux combination, where it needed -lrt on the link line. #394 (1.5.10)
• Windows build fix for compiling shaders finding the right oslc.exe. #399 (1.5.11)

Documentation:

• Clarified docs about floor(). (1.5.8)
• Clarified that oren_nayar() is the name of the function, not orennayar (it was not consistent). (1.5.8) (#375)
• backfacing() was previously left out of the docs. (1.5.8) (#376)
• Documented the specific names that should be used with getattribute() to retrieve common camera parameters. We should expect these to be the same for all renderers (though individual renderers may also support additional attribute queries). #393 (1.5.9)
• Clarify that we intend for getattribute() to be able to retrieve "userdata" (aka primitive variables) if no attribute is found with the matching name. #395 (1.5.10)

Release 1.4.1 - 19 Dec 2013 (compared to 1.4.0)

• Guard matrix*point transformations against possible division by zero.
• Fix subtle bug with splines taking arrays, where the number of knots passed was less than the full length of the array, and the knots had derivatives -- the derivatives would be looked up from the wrong spot in the array (and could read uninitialized portions of the array).
• testshade/testrender - Fix timer call that wasn't correctly reporting execution time versus total time.
• Fix incorrect function declarations for the no-bitcode case (only affected Windows or if a site purposely built without precompiled bitcode for llvm_ops.cpp).
• Build: more robust detection of clang, for older cmake versions.
• Build: handle 3-part version numbers for LLVM installations.
• Build: Fix USE_EXTERNAL_PUGIXML versus USING_OIIO_PUGI issue.

Release 1.4.0 - 12 November 2013 (compared to 1.3)

Language, standard libary, and compiler changes (for shader writers):

• Simplex noise: new noise varieties "simplex" and "usimplex" are faster than Perlin noise (and MUCH faster for the 4-D variety), but has a somewhat different appearance. Judge for yourself, use whichever noise suits your purpose.
• oslc now catches mismatches between the format string and the types of arguments to format(), printf(), fprintf(), warning(), and error().
• oslc now gives a compile error when trying to use a function as if it were an ordinary variable. (1.3.2)
• Improvement to oslc function type checking -- allow more nuanced matching of polymorphism based on return types. First we check for identical return types, then we test allowing non-identical spatial triples to match, then finally we allow any return type to match.
• New ShadingSystem attribute "debug_uninit", which when set to nonzero tries to detect use of uninitialized variables at runtime. (Off by default because it's very expensive, just use if you are debugging.)
• Implemented the OSL aastep() function, which was always described in the docs but never implemented.
• The texture lookup functions all take new optional parameters, "missingtexture", (color), "missingalpha", (float), which when supplied will substitute that color and alpha for missing or broken textures, rather than treating it as an error condition.
• New gettextureinfo() queries: "datawindow", "displaywindow" (both take an int[4] as destination argument).

ShadingSystem API changes and new options (for renderer writers):

• New ShadingSystem attribute "renderer_outputs" enumerates the renderer outputs (AOVs) explicitly, so that elision of unused outputs can be done with full understanding of which params will or will not be sued. Beware: if you enable "opt_elide_unconnected_outputs", you MUST pass "renderer_outputs" or your AOVs may be eliminated!

Performance improvements:

• "Middleman" optimization notices when you have 3 layers A,B,C with connections A.Aout -> B.Bin and B.Bout -> C.Cin, an Bout is simply copied unconditionally from Bin. In this case, Aout is connected directly to Cin, potentially leading to further optimizations, including layer B getting culled entirely.
• Layer-to-layer global propagation: Notice cases where an upstream output is guaranteed to be aassigned a global variable (such as N or u) and then alias the downstream parameter to that global (eliminating the connection and possibly culling the upstream layer entirely).
• Improve constant propagation from layer to layer (it used to do so only if the output of the earlier layer was never used in the upstream layer; but actually it's ok for it to be read, as long as it's not rewritten).
• Runtime constant-folding of cellnoise() calls.
• Local variables that are arrays initialized with float, int, or string constants have been greatly optimized. If that's the only time anything is written into the array, it will be turned into a true static constant with no per-shader-invocation initialization or allocation costs. Thus, it is no longer expensive to use a large array of constants as a table... it may look like a per-shade cost to set up the array, but by the time the optimizer gets done with it, it is not.
• Improved runtime constant-folding of max/min (now works for the integer case, as well as previously working for the float-based types).
• Runtime constant-folding of cos, sin, acos, asin, normalize, inversesqrt, exp, exp2, expm1, log, log2, log10, logb, erf, erfc, radians, degrees.
• Optimization that speeds up certain closure manipulations and can cut overhead especially for relatively simple shaders.
• New peephole optimizations for two common patterns: (1) add A B C ; sub D A C => [add A B C;] assign D B and the same if the order of add & sub are switched. (2) OP A B... ; assign A C => OP C B... as long as A is not subsequently used and OP fully overwrites A and writes to no other variables.
• Constant folding of Dx, Dy, Dz, area, and filterwidth, when passed a constant (the deriv will be 0 in that case).
• Substantial multithread speedups by eliminating testing of some shared variables.
• Constant folding of add & sub for the mixed float/triple cases.
• Speed up closure construction by combining the closure primitive with its (nearly inevitable) multiplication by weight, into a single internal operation.
• The OSLQuery library has been sped up by 20x when querying the parameters of large shaders.

Bug fixes:

• Fix 'debugnan' tendency to give false positives for certain assignments to arrays and multi-component variables (colors, points, etc.).
• The integer versions of min(), max(), and clamp() were not working properly. (1.3.1)
• fmod(triple,triple,float) was not working properly in Windows. (1.3.2)
• Avoid incorrect heap addressing when retrieving a symbol's address. (1.3.2)
• Fix for a bug where an early 'return' from a shader could lead to output parameters not being properly copied to the inputs of their downstream connections. (1.3.2)
• Fix bug where filterwidth() didn't properly mark itself as needing derivatives of its argument. (1.3.2)
• Bug fix: Was not properly initializing the default values of output params if they were written but never subsequently read.
• Better error handling for missing pointclouds.
• Fixed improper initialization of arrays of closures.
• Fixed constant folding bug for the split() function.
• Fixed constant folding bug for pow(x,2.0).

Under the hood:

• Eliminate use of custom DEBUG preprocessor symbol in favor of the more standard NDEBUG (beware: its sense is reversed).
• All references to and vestiges of TBB have been removed.

Build & test system improvements and developer goodies:

• testshade: --options lets you set arbitrary options to the ShadingSystem for test runs.
• Added CMake option 'ENABLERTTI' that enables use of RTTI for sites that must link against an RTTI-enabled LLVM (the default is to assume LLVM is built without RTTI, so we don't use it either). (1.3.1)
• Fix some ambiguity about which variety of shared_ptr we are using -- this could produce problems in apps that include the OSL headers but also use different shared_ptr varieties.
• Fix a variety of build issues and warnings under Windows.
• Work around CMake bug where on some platforms, CMake doesn't define the 'NDEBUG' when making the 'RelWithDebInfo' target (which is sometimes used for profiling). (1.3.1)
• Add Make/CMake option 'USE_EXTERNAL_PUGIXML' which if set to nonzero will find and use a system-installed PugiXML rather than assuming that it's included in libOpenImageIO. When used, it will also use the environment variable PUGIXML_HOME (if set) as a hint for where to find it, in case it's not in a usual system library directory. (1.3.1)
• Nicer debug printing (for developers) when an op doesn't have an associated source line. (1.3.2)
• Reorder include directories for building LLVM bitcode so that the openimageio, ilmbase and boost directories are ahead of any system directories given by llvm-config --cxxflags. This avoids the LLVM bitcode getting compiled against different library versions than the rest of the code if multiple versions are installed.
• Have debug_groupname and debug_layername apply to LLVM debugging info as well.
• Support for LLVM 3.3.
• Fix compiler warnings for clang 3.3 and libc++.
• CMake files now more carefully quote assembled file paths to more gracefully handle paths with spaces in them.
• CMakeLists.txt has been moved to the top level (not in src/) to conform to the usual CMake conventions.

Documentation:

• Eliminate references to OSL random() function; it was never implemented and nobody seemed to miss it or have a compelling use case. (1.3.1)

Release 1.3.3 - 11 July 2013 (compared to 1.3.2)

• Fix bug in the implementation of filterwidth() when passed a constant (for which no derivative could be taken).
• Changes to support LLVM 3.3.

Release 1.3.2 - 19 Jun 2013 (compared to 1.3.1)

• fmod(triple,triple,float) was not working properly in Windows.
• Nicer debug printing (for developers) when an op doesn't have an associated source line.
• Avoid incorrect heap addressing when retrieving a symbol's address.
• oslc new gives a compile error when trying to use a function as if it were an ordinary variable.
• Fix for a bug where an early 'return' from a shader could lead to output parameters not being properly copied to the inputs of their downstream connections.
• Fix bug where filterwidth() didn't properly mark itself as needing derivatives of its argument.

Release 1.3.1 - 15 May 2013 (compared to 1.3.0)

• The integer versions of min(), max(), and clamp() were not working properly.
• Added CMake option 'ENABLERTTI' that enables use of RTTI for sites that must link against an RTTI-enabled LLVM (the default is to assume LLVM is built without RTTI, so we don't use it either).
• Work around CMake bug where on some platforms, CMake doesn't define the 'NDEBUG' when making the 'RelWithDebInfo' target (which is sometimes used for profiling).
• Docs: Eliminated discussion of random(), which was never implemented and we can't think of a good use case.
• Add Make/CMake option 'USE_EXTERNAL_PUGIXML' which if set to nonzero will find and use a system-installed PugiXML rather than assuming that it's included in libOpenImageIO. When used, it will also use the environment variable PUGIXML_HOME (if set) as a hint for where to find it, in case it's not in a usual system library directory.

Release 1.3.0 - 14 Feb 2013 (compared to 1.2)

Language, standard libary, and compiler changes (for shader writers):

• pointcloud_write() allows shaders to write data and save it as a point cloud.
• spline now accepts a "constant" interpolation type, which interpolates with discrete steps.
• isconnected(var) returns true if var is a shader parameter and is connected to an earlier layer. This is helpful in having shader logic that can discern between a connected parameter versus a default.
• Whole-array assignment is now supported. That is, if A and B are arrays of the same type and length(A) >= length(B), it is legal to write A=B without needing to write a loop to copy each element separately.
• stoi() and stof() convert strings to int or float types, respectively (just like the identically-named functions in C++11). These do properly constant-fold during runtime optimization if their inputs can be deduced.
• split() splits a string into tokens and stores them in the elements of an array of strings (and does constant-fold!).
• distance(point A, point B, point Q) gives the distance from Q to the line segment joining A and B. This was described by the OSL spec all along, but somehow was not properly implemented.

ShadingSystem API changes and new options (for renderer writers):

• Default implementation of all the pointcloud_*() functions in RendererServices, if Partio is found at build time.
• ShadingSystem attribute "compile_report" controls whether information should be sent to the renderer for each shading group as it compiles. (The default is now to be more silent, set this to nonzero if you want to see the old per-group status messages.)
• ShadingSystem attribute "countlayerexecs" adds debugging code to count the total number of shader layer executions (off by default; it slows shader execution down slightly, is only meant for debugging).
• Add a parameter to OSLCompiler::compile to specify the path to the stdosl.h file.
• New call: ShadingSystem::LoadMemoryCompiledShader() loads a shader with OSO data from a memory buffer, rather than from a file.

Performance improvements:

• Reduce instance symbol memory use, lowering OSL-related memory by 1/2-2/3 for large scenes.
• Identical shader instances within a shader group are automatically merged -- this can have substiantial performance and memory improvements for very complex shader groups that may (inadvertently, for convenience, or as an artifact of certain lookdev tools) have multiple instances with identical input parameters and connections. We have seen some shots that render up to 20% faster with this change.
• Better constant-folding for pointcloud_get (if indices are known).
• Speed up implementation of exp() for some Linux platform (works around a known glibc issue).
• Speed up of mix() by making it a built-in function (rather than defined in stdosl.h) and doing aggressive constant folding on it. Also some special cases to try to avoid having mix() unnecessarily trigger execution of earlier layers when one or both of its arguments is a connected shader param and the mix value turns out to be 0 or 1.
• Runtime optimization now includes constant-folding of getattribute() calls, for those attributes which are scene-wide (such as renderer options that apply to the whole frame).
• Improvements in the algorithm that tracks which symbols need to carry derivatives around results in MUCH faster compile times for extremely complex shaders.
• Improve bad performance for shaders that call warning() prolifically, by imposing a maximum number of shader warnings that are echoed back to the renderer (controlled by ShadingSystem attribute "max_warnings_per_thread", which defaults to 100; 0 means that there is no maximum).

Bug fixes and minor improvements:

• Fix incorrect oso output of matrix parameter initialization. (This did not affect shader execution, but could result in oslquery/oslinfo not reporting default matrix parameter values correctly.)
• Bug fix: oslinfo didn't print int metadata values properly.
• oslc better error checking when calling a variable as if it were a function.
• Parsing of oso files was broken for compiled shaders that had string metadata whose metadata value contained the '}' character.
• Pointcloud function bug fixes: now robust to being passed empty filenames, or calling pointcloud_get when count=0.
• Fix crash with C preprocessor when #include fails or no shader function is defined.
• Improve error reporting when parsing oso, especially in improving the error messages when an old renderer tries to load a .oso file created by a "newer" oslc, and the oso contains new instruction opcodes that the older renderer didn't know about.
• oslc now gives a helpful error message, rather than hitting an assertion, if you try to index into a non-array or non-component type.
• Broken "XYZ" color space transformations because of confusion between "xyz" and "XYZ" names.
• oslc: correctly catch errors with integer literals that overflow.
• oslc: proper error, rather than assertion, for 'closure color * closure color'.
• oslc: proper handling of preprocessor errors when stdosl.h is in a path containing spaces.
• Fix bugs in the OSL exit() function.
• Don't error/warn if metadata name masks a global scope name.

Under the hood:

• Simplify code generation of binary ops involving closures.

Build & test system improvements and developer goodies:

• Many, many fixes to enable building and correct running of OSL on Windows. Too many to list individually, let's just say that OSL 1.3 builds and runs pretty robustly on Windows, older versions did not.
• Remove unused OpenGL and GLEW searching from CMake files.
• Fix a variety of compiler warnings, particularly on newer compilers, 32 bit platforms, and Windows.
• Find LLVM correctly even when using "svn" LLVM versions.
• Adjust failure threshold on some tests to account for minor platform differences.
• New minimum OIIO version: 1.1.
• CMake fixes: Simplify searching for and using IlmBase, and remove unneeded search for OpenEXR.
• Find Partio (automatically, or using 'make PARTIO_HOME=...'), and if found, use it to provide default RendererServices implementations of all the pointcloud-related functions.
• Make/CMake STOP_ON_WARNING flag (set to 0 or 1) controls whether the build will stop upon any compiler warning (default) or if it should keep going (=0).
• Fixed bad interaction between weave preprocessor, OIIO::Strutil::format, and gcc 4.7.2.
• Fixes for static linkage of liboslcomp.
• Addressed compilation errors on g++ 4.7.2.
• Improved logic and error reporting for finding OpenImageIO at build time.
• Add support for linking to static LLVM libraries, and for specifying a particular LLVM version to be used.
• New BUILDSTATIC option for CMake/Make allows building of static OSL libraries.
• Fixes to allow OSL to use LLVM 3.2.
• Fixes to allow OSL to be compiled by clang 3.2.
• Fixes to allow building on Windows with MinGW.
• Fix for building from a chroot where the host may be, e.g., 64 bit, but the target is 32 bit.
• Minimize cmake output clutter for things that aren't errors, unless VERBOSE=1.
• Various fixes to get OSL building and running on FreeBSD.
• Cmake/make option USE_LLVM_BITCODE to be able to force LLVM bitcode compilation on or off (defaults to on for Windows, off for Unix/Linux).

Documentation:

• Clarify that documentation is licensed under Creative Commons 3.0 BY.
• Clean up OSL Spec discussion of built-in material closures.
• Overhaul the suggested metadata conventions in the OSL spec (now conforms to the conventions used by Katana).

Release 1.2.1 - 6 Nov, 2012 (compared to 1.2.0)

• Fix incorrect oso output of matrix parameter initialization. (This did not affect shader execution, but could result in oslquery/oslinfo not reporting default matrix parameter values correctly.)
• Build: remove unused OpenGL and GLEW searching from CMake files.
• Build: Fix a variety of compiler warnings, particularly on newer compilers, 32 bit platforms, and Windows.
• Build: Find LLVM correctly even when using "svn" LLVM versions.
• Bug fix: oslinfo didn't print int metadata values properly.

Release 1.2.0 - Aug 30, 2012 (compared to 1.1)

Note: this is more or less the production-hardened version of OSL that was used to complete Men in Black 3, The Amazing Spider-Man, and Hotel Transylvania.

New tools/utilities:

• New program "testrender" is a tiny ray-tracing renderer that uses OSL for shading. Features are very minimal (only spheres are permitted at this time) and there has been no attention to performance, but it demonstrates how the OSL libraries may be integrated into a working renderer, what interfaces the renderer needs to supply, and how the BSDFs/radiance closures should be evaluated and integrated (including with multiple importance sampling).
• shaders/ubersurface.osl is an example of a general purpose surface shader.

Language, standard libary, and compiler changes:

• texture()/texture3d() support for subimage/face selection by name as well as by numeric index.
• getattribute() performs automatic type conversions that mostly correspond to the kind of automatic type casting you would get from ordinary assignments in OSL. For example, getattribute("attrib",mycolor) used to fail if "attrib" turned out to be a float rather than a color; but now it succeeds and copies the float value to all three channels of mycolor.

ShadingSystem API changes and new options:

• Remove unused 'size' parameter from the register_closure API.

Optimization improvements:

• Constant-fold pointcloud_search calls when the position is a constant if the search returns few enough results, by doing the query at optimization time and putting the results into new constant arrays.
• Matrix parameters initialized by m=matrix(constA,constB,...) now statically initialize, and no longer need to run initialization code each time the shader executes.

Bug fixes and minor improvements:

• Fix pointcloud_search to optionally take a 'sort' parameter, as originally documented.
• Unit tests weren't properly run as part of the testsuite.
• Track local+temp memory usage of optimized shaders and consider it an error if a shader needs more than a maximum amount at runtime, set with the "max_local_mem_KB" attribute.
• Add pointcloud statistics.
• Fix derivative error for sincos() when the inputs have no derivatives but the outputs do.
• Bug fix to vector-returning Gabor noise (it could previously generate different values for different platforms).
• printf() of closures built from other closures allows for proper recursive printing of the closure tree.

Build & test system improvements and developer goodies:

• Simplify the namespace scheme.
• Remove support for certain old dependencies: OIIO versions < 0.10, LLVM < 3.0, and Boost < 1.40.
• Lots of little fixes to solve compiler warnings on various compilers.
• Support for newer OSX releases, particularly if /usr/bin/cpp-4.2 is not found.
• Better support for Boost::wave (portable C preprocessor replacement). Build with 'make USE_BOOST_WAVE=1' to force Wave use instead of system cpp.
• You can select a custom LLVM namespace with 'make LLVM_NAMESPACE=...'.
• Symbols that are not part of the OSL public APIs are now hidden from the linker in Linux/OSX if the CMake variable HIDE_SYMBOLS is on.
• New Makefile/CMake option LLVM_STATIC can be used to use static LLVM libraries rather than the default dynamic libraries.
• Support for LLVM 3.1.
• Support for building with Clang 3.1 (lots of warning fixes).
• Makefile/CMake variable EXTRA_CPP_DEFINITIONS allows you to inject additional compiler flags that you may need to customize the build for your site or a choice of unusual compiler.
• Add support for 'PROFILE=1' builds that are appropriate for use with a profile.

Release 1.1.0 - Mar 14, 2012 (compared to 1.0.0)

Language, standard libary, and compiler changes:

• Allow closures as parameters to closures.
• New constants: M_2PI, M_4PI
• Generic noise: noise("noisetype",coords,...)
• Gabor noise (anisotropic, automatically antialiased) via noise("gabor").
• Fix mod/fmod discrepancy: fmod() now matches C, mod() always returns a positive result like in RSL.
• Allow "if (closure): and "if (!closure)" to test if a closure is empty or not.
• New optional parameter to trace(): "traceset" allows you to specify a named geometry set for tracing.

ShadingSystem API changes and new options:

• New "greedyjit" option will optimize & JIT all shader groups up front, concurrently, without locking.
• Add a way to name shader groups.
• attribute("options",...) lets you set a bunch of options at once.
• Options to enable/disable individual optimizations (mostly useful for debugging)

Optimization improvements:

• Allow block alias tracking on non-constants when it's safe.
• Track "stale" values to eliminate pointless assignments.
• Eliminate redundant "useparam" ops.
• Assignments to output parameters that are not connected to any downstream layers are now eliminated.
• More aggressive elision of ops that only write to symbols that won't be subsequently used.
• More careful identification and removal of parameters (input and output) that are both unused in the shader and not connected downstream.

Bug fixes and minor improvements:

• Minor blackbody fixes.
• Bug fix: don't mark constants as having their derivatives taken.
• Clamp splineinverse() for out-of-knot-range x input.
• Bug fix: the optimization of "a=b; a=c" was incorrect if c was an alias for a (it incorrectly eliminated the first assignment).
• Bug fix: work around LLVM thread safety issues during JIT.
• Bug fix: symbol_data() wasn't returning the right address for non-heap parameters.
• Bug fix: optimization errors related to break, continue, and return not properly marking the next instruction as a new basic block.
• Bug fix: luminance() with derivatives didn't work.
• Bug fix: in code generation of structure initializers.
• Improved error messages from ConnectShaders.
• Bug fix: type checking bug could case non-exactly-matching polymorphic functions to coerce a return value even when that was not intended.
• Type checking improvements: Make sure point-point is a vector expression, and point+vector & point-vector are point expressions.

Build & test system improvements and developer goodies:

• testsuite overhauls:
  • run each test both optimized and not
  • generate all tests in build, not directly in ./testsuite
  • greatly simplify the run.py scripts
• Much more detailed debugging logs of the optimization process.
• Upgrade to clang/llvm 3.0.
• Lots of infrastructure to make debugging the optimizer easier. Including new options debug_groupname, debug_layername, only_groupname.
• Improved the build system's LLVM-finding logic.
• Fix warnings from gcc 4.6.

Release 1.0.0 - Oct 12, 2011

• Modified testshade (and the underlying SimpleRender class) to handle several standard named coordinate systems such as "camera", "screen", "NDC", "raster."
• blackbody() and wavelength_color().
• New ShadingSystem configuration attribute: "colorspace" lets you explain to OSL what RGB really means (e.g., "Rec709", "sRGB", "NTSC", etc.). The luminance(), blackbody(), wavelength_color, and conversion to/from XYZ now takes this into account correctly.
• rotate() (always in spec, never implemented)

Release 0.6.2 - Sept 29, 2011

• Statistics overhaul -- added optimization stats, eliminated unused ones.
• Allow a shader parameter to mask a global built-in function with only a warning, and improve scope conflict errors by pointing out the file and line of the previous definition.
• Altered the RendererServices API to add transform_points() method, which allows renderers to support nonlinear transformations (i.e., those that are not expressible as a 4x4 matrix).
• Issue a renderer error when unknown coordinate system names are used (can be turned of by setting the new ShadingSystem attribute "unknown_coordsys_error" to false).
• New OSL built-in function: splineinverse().

Release 0.6.1 - Sept 20, 2011

• Be more aggressive in freeing shader instance memory that's no longer needed after optimization and LLVM JIT. This greatly reduces OSL-related memory consumption for scenes with large numbers of very complicated shading networks.
• Add Dz() which is helpful for apps that use OSL to shade volumes. At present, we only correctly compute Dz(P), all other Dz() queries return 0.
• Additional statistics on how many instances and groups compile, and how many are empty after all optimizations are performed.
• Make sure all the relevant statistics can be queried via ShadingSystem::getattribute.

Release 0.6.0 - Sept 9, 2011

• ShadeExec API overhaul -- an app using it no longer needs ShadingSystemImpl internal knowledge.
• Thread-parallel runtime optimization and LLVM JIT of different shader groups.
• Optimizations: runtime constant folding of arraylength and regex_search, new instruction 'arraycopy' will copy an entire array at once.
• Renamed patterns.h to oslutil.h.
• Do not generate unnecessary code when optional texture parameters are set to their default values.
• Restore long-lost ability for layers to run unconditionally (not lazily) if they were marked as "non-lazy" (for example, if they write to globals.
• Make the "debugnan" attribute work again -- when turned on, code will be inserted after every op to be sure that no NaN or Inf values are generated, and also verify that shader inputs (globals) don't have NaN or Inf values passed in by the renderer. A similar facility existed a long time ago, but we lost that functionality when we switched from the interpreter to LLVM.
• Looks for release versions of LLVM-2.9 (allows using a Macports LLVM installation).

Release 0.5.4 - Jul 21, 2011

• Several fixes related to arrays of structs, and structs containing other structs.
• Fixed arrays of closures.
• Removed support for old LLVM 2.7, nobody seemed to be using it any more.
• Changed the definition of dict_find() to return -1 for an invalid dictionary, to distinguish it from 0 meaning that the query failed but the dictionary itself was valid.
• Make array parameters safe to convert to constants during runtime optimization.
• Support derivatives in pointcloud searches.
• Fixed several runtime optimizer bugs.
• Fixed a bug where environment() calls with an optional "alpha" parameter that has derivatives was overwriting memory.
• Fixed code generation bug for a*=b and a/=b.
• Automatically initialize all local string variables to NULL, to avoid bad pointers for uninitialized strings.
• Bug fix: dict_value() wasn't properly marking its argument as writable.
• Automatic range checking of array and component access.
• Fix uninitialized derivatives for pointcloud().
• Speed up getattribute() calls by caching information about failed getattribute queries in the ShadingContext.
• Fix to constant folding of gettextureinfo: a failed lookup should not fold, because we want the error to occur in shader execution, not during optimization.
• Refactor, clean up, and comment testshade.
• oslc now gives an error on non-void functions that fail to return a value.
• Fixed implementation of area() that could generate an assertion.
• Fix escape sequences in string literals: we were handling it correctly for printf-like format strings, but not other string literals.
• break and continue now work properly (just like in C/C++).
• You can now return from anywhere in a user function (multiple times if you want), just like C/C++, and are no longer restricted to the only return statement being the last statement of the function.
• New include file for shaders: patterns.h. Now, it only includes a handy 'wireframe()' function, but will expand for other useful things.
• New function: int getmatrix(from,to,M) is like the matrix(from,to) constructor, but returns a success value so a shader can tell if the named coordinate systems failed to be found by the renderer.

Release 0.5.3 - Apr 19, 2011

• Fix missing derivatives for sign() function.
• Fix closure color type size (crashes).
• Fix bug with environment() when passed "alpha" pointers with derivatives.
• Improve error messages for getmessage/setmessage to catch the most common sources of non-deterministic behavior.
• Bug fix when constant-folding gettextureinfo().
• Fix mismatched prototype for subsurface() closure.
• Texture errors encountered in shader constant folding are now properly reported to the renderer.
• Allow functions to have array parameters of unspecified length.
• Fix subtle bug related to lifetime analysis of variables in loops (led to incorrect optimizations).

Release 0.5.2 - Mar 14, 2011

• Windows: use boost::wave instead of external cpp; various other Windows compilation fixes.
• texture & environment now take an optional "interp" parameter that overrides the interpolation/filtering method (valid arguments: "smartcubic", "cubic", "linear", "closest").
• Bug fixes to getmessage() and its handling of derivatives, which includes a slight RendererServices API change.