ptex

Simple GUI example with ptex texture mapping.

Coordinates

Right-handed coorinate, Y up, counter clock-wise normal definition.

Limitation

Face must be triangle or quad. No n-gons(n >= 5) are supported.

Requirements

• git
• cmake
• OpenGL 2.x

Setup

Clone ptex-aarch64(Added reading ptex data from memory) https://github.com/syoyo/ptex-aarch64.git to this directory.

$ cd $nanort/examples/ptex
$ git clone https://github.com/syoyo/ptex-aarch64.git

cmake build

Build on Linux/MacOSX

$ rmdir build
$ mkdir build
$ cd build
$ cmake ..
$ make

Build on Windows

$ rmdir /s /q build
$ mkdir build
$ cd build
$ cmake -G "Visual Studio 15 2017" -A x64 ..

Open .sln and build it with Visual Studio 2017.

Usage

Prepare ptex scene. for example download some ptex scene for example from http://ptex.us/samples.html

Edit config.json and setup file path to .obj and .ptx, then

$ cd build
$ ./ptexrt ../config.json

Note on quad primitive

Quad must be planar.

We tessellate a quad to two-triangles and build BVH, then do ray-triangle intersection. To compute correct UV, we store

config.json

• obj_filename : filepath : filenam of wavefront obj mesh(.obj)
• ptex_filename : filepath : filenam of ptex(.ptx)
• dump_ptex : true/false : Dump ptex data after loading it.

TODO

• Read vertex/index information from .ptx so that we can render pentagon example(its represented as 5 quads in .ptx, but .obj uses single face with 5 verties)
• Support Quad primitive in ray traversal. http://graphics.cs.kuleuven.be/publications/LD05ERQIT/index.html

Mouse operation

• left mouse = rotate
• shift + left mouse = translate
• tab + left mouse = dolly(Z axis)