Add support for s3tc, pvrtc, and etc1 compressed textures and loading…

… them from KTX files.
CesiumGS · Dec 19, 2016 · 4cc7559 · 4cc7559
1 parent 9d7348d
commit 4cc7559
Show file tree

Hide file tree

Showing 29 changed files with 1,995 additions and 52 deletions.
diff --git a/CHANGES.md b/CHANGES.md
@@ -19,6 +19,7 @@ Change Log
 * Added `divideComponents` function to `Cartesian2`, `Cartesian3`, and `Cartesian4`. [#4750](https://github.com/AnalyticalGraphicsInc/cesium/pull/4750)
 * Added `WebGLConstants` enum.  Previously, this was part of the private Renderer API. [#4731](https://github.com/AnalyticalGraphicsInc/cesium/pull/4731)
 * Fixed tooltips for gallery thumbnails in Sandcastle [#4702](https://github.com/AnalyticalGraphicsInc/cesium/pull/4702)
+* Added compressed texture support. The supported extensions are `WEBGL_compressed_s3tc`, `WEBGL_compressed_texture_pvrtc`, and `WEBGL_compressed_texture_etc1`. [#4758](https://github.com/AnalyticalGraphicsInc/cesium/pull/4758)
 
 ### 1.28 - 2016-12-01
 

diff --git a/Source/Core/PixelFormat.js b/Source/Core/PixelFormat.js
@@ -69,6 +69,78 @@ define([
          */
         LUMINANCE_ALPHA : WebGLConstants.LUMINANCE_ALPHA,
 
+        /**
+         * A pixel format containing red, green, and blue channels that is DXT1 compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGB_DXT1 : WebGLConstants.COMPRESSED_RGB_S3TC_DXT1_EXT,
+
+        /**
+         * A pixel format containing red, green, blue, and alpha channels that is DXT1 compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGBA_DXT1 : WebGLConstants.COMPRESSED_RGBA_S3TC_DXT1_EXT,
+
+        /**
+         * A pixel format containing red, green, blue, and alpha channels that is DXT3 compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGBA_DXT3 : WebGLConstants.COMPRESSED_RGBA_S3TC_DXT3_EXT,
+
+        /**
+         * A pixel format containing red, green, blue, and alpha channels that is DXT5 compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGBA_DXT5 : WebGLConstants.COMPRESSED_RGBA_S3TC_DXT5_EXT,
+
+        /**
+         * A pixel format containing red, green, and blue channels that is PVR 4bpp compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGB_PVRTC_4BPPV1 : WebGLConstants.COMPRESSED_RGB_PVRTC_4BPPV1_IMG,
+
+        /**
+         * A pixel format containing red, green, and blue channels that is PVR 2bpp compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGB_PVRTC_2BPPV1 : WebGLConstants.COMPRESSED_RGB_PVRTC_2BPPV1_IMG,
+
+        /**
+         * A pixel format containing red, green, blue, and alpha channels that is PVR 4bpp compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGBA_PVRTC_4BPPV1 : WebGLConstants.COMPRESSED_RGBA_PVRTC_4BPPV1_IMG,
+
+        /**
+         * A pixel format containing red, green, blue, and alpha channels that is PVR 2bpp compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGBA_PVRTC_2BPPV1 : WebGLConstants.COMPRESSED_RGBA_PVRTC_2BPPV1_IMG,
+
+        /**
+         * A pixel format containing red, green, and blue channels that is ETC1 compressed.
+         *
+         * @type {Number}
+         * @constant
+         */
+        RGB_ETC1 : WebGLConstants.COMPRESSED_RGB_ETC1_WEBGL,
+
         /**
          * @private
          */
@@ -79,7 +151,16 @@ define([
                    pixelFormat === PixelFormat.RGB ||
                    pixelFormat === PixelFormat.RGBA ||
                    pixelFormat === PixelFormat.LUMINANCE ||
-                   pixelFormat === PixelFormat.LUMINANCE_ALPHA;
+                   pixelFormat === PixelFormat.LUMINANCE_ALPHA ||
+                   pixelFormat === PixelFormat.RGB_DXT1 ||
+                   pixelFormat === PixelFormat.RGBA_DXT1 ||
+                   pixelFormat === PixelFormat.RGBA_DXT3 ||
+                   pixelFormat === PixelFormat.RGBA_DXT5 ||
+                   pixelFormat === PixelFormat.RGB_PVRTC_4BPPV1 ||
+                   pixelFormat === PixelFormat.RGB_PVRTC_2BPPV1 ||
+                   pixelFormat === PixelFormat.RGBA_PVRTC_4BPPV1 ||
+                   pixelFormat === PixelFormat.RGBA_PVRTC_2BPPV1 ||
+                   pixelFormat === PixelFormat.RGB_ETC1;
         },
 
         /**
@@ -99,6 +180,75 @@ define([
         isDepthFormat : function(pixelFormat) {
             return pixelFormat === PixelFormat.DEPTH_COMPONENT ||
                    pixelFormat === PixelFormat.DEPTH_STENCIL;
+        },
+
+        /**
+         * @private
+         */
+        isCompressedFormat : function(pixelFormat) {
+            return pixelFormat === PixelFormat.RGB_DXT1 ||
+                   pixelFormat === PixelFormat.RGBA_DXT1 ||
+                   pixelFormat === PixelFormat.RGBA_DXT3 ||
+                   pixelFormat === PixelFormat.RGBA_DXT5 ||
+                   pixelFormat === PixelFormat.RGB_PVRTC_4BPPV1 ||
+                   pixelFormat === PixelFormat.RGB_PVRTC_2BPPV1 ||
+                   pixelFormat === PixelFormat.RGBA_PVRTC_4BPPV1 ||
+                   pixelFormat === PixelFormat.RGBA_PVRTC_2BPPV1 ||
+                   pixelFormat === PixelFormat.RGB_ETC1;
+        },
+
+        /**
+         * @private
+         */
+        isDXTFormat : function(pixelFormat) {
+            return pixelFormat === PixelFormat.RGB_DXT1 ||
+                   pixelFormat === PixelFormat.RGBA_DXT1 ||
+                   pixelFormat === PixelFormat.RGBA_DXT3 ||
+                   pixelFormat === PixelFormat.RGBA_DXT5;
+        },
+
+        /**
+         * @private
+         */
+        isPVRTCFormat : function(pixelFormat) {
+            return pixelFormat === PixelFormat.RGB_PVRTC_4BPPV1 ||
+                   pixelFormat === PixelFormat.RGB_PVRTC_2BPPV1 ||
+                   pixelFormat === PixelFormat.RGBA_PVRTC_4BPPV1 ||
+                   pixelFormat === PixelFormat.RGBA_PVRTC_2BPPV1;
+        },
+
+        /**
+         * @private
+         */
+        isETC1Format : function(pixelFormat) {
+            return pixelFormat === PixelFormat.RGB_ETC1;
+        },
+
+        /**
+         * @private
+         */
+        compressedTextureSize : function(pixelFormat, width, height) {
+            switch (pixelFormat) {
+                case PixelFormat.RGB_DXT1:
+                case PixelFormat.RGBA_DXT1:
+                case PixelFormat.RGB_ETC1:
+                    return Math.floor((width + 3) / 4) * Math.floor((height + 3) / 4) * 8;
+
+                case PixelFormat.RGBA_DXT3:
+                case PixelFormat.RGBA_DXT5:
+                    return Math.floor((width + 3) / 4) * Math.floor((height + 3) / 4) * 16;
+
+                case PixelFormat.RGB_PVRTC_4BPPV1:
+                case PixelFormat.RGBA_PVRTC_4BPPV1:
+                    return Math.floor((Math.max(width, 8) * Math.max(height, 8) * 4 + 7) / 8);
+
+                case PixelFormat.RGB_PVRTC_2BPPV1:
+                case PixelFormat.RGBA_PVRTC_2BPPV1:
+                    return Math.floor((Math.max(width, 16) * Math.max(height, 8) * 2 + 7) / 8);
+
+                default:
+                    return 0;
+            }
         }
     };
 

diff --git a/Source/Core/WebGLConstants.js b/Source/Core/WebGLConstants.js
@@ -315,6 +315,21 @@ define([
         UNPACK_COLORSPACE_CONVERSION_WEBGL : 0x9243,
         BROWSER_DEFAULT_WEBGL : 0x9244,
 
+        // WEBGL_compressed_texture_s3tc
+        COMPRESSED_RGB_S3TC_DXT1_EXT : 0x83F0,
+        COMPRESSED_RGBA_S3TC_DXT1_EXT : 0x83F1,
+        COMPRESSED_RGBA_S3TC_DXT3_EXT : 0x83F2,
+        COMPRESSED_RGBA_S3TC_DXT5_EXT : 0x83F3,
+
+        // WEBGL_compressed_texture_pvrtc
+        COMPRESSED_RGB_PVRTC_4BPPV1_IMG : 0x8C00,
+        COMPRESSED_RGB_PVRTC_2BPPV1_IMG : 0x8C01,
+        COMPRESSED_RGBA_PVRTC_4BPPV1_IMG : 0x8C02,
+        COMPRESSED_RGBA_PVRTC_2BPPV1_IMG : 0x8C03,
+
+        // WEBGL_compressed_texture_etc1
+        COMPRESSED_RGB_ETC1_WEBGL : 0x8D64,
+
         // Desktop OpenGL
         DOUBLE : 0x140A,