s3tc compression support

1 files changed, 13 insertions, 1 deletions

diff --git a/src/library_gl.js b/src/library_gl.js
index 1b6ec5c0..9928ab5d 100644
--- a/src/library_gl.js
+++ b/src/library_gl.js
@@ -100,6 +100,16 @@ var LibraryGL = {
       var alignedRowSize = roundedToNextMultipleOf(plainRowSize, alignment);
       return (height <= 0) ? 0 :
                ((height - 1) * alignedRowSize + plainRowSize);
+    },
+
+    ensureCompression: function() {
+      if (GL.ensureCompression.done) return;
+      GL.ensureCompression.done = true;
+
+      var ext = Module.ctx.getExtension('WEBGL_compressed_texture_s3tc') ||  
+                Module.ctx.getExtension('MOZ_WEBGL_compressed_texture_s3tc') ||  
+                Module.ctx.getExtension('WEBKIT_WEBGL_compressed_texture_s3tc');  
+      assert(ext, 'Failed to get texture compression WebGL extension');
     }
   },
 
@@ -274,6 +284,7 @@ var LibraryGL = {
   },
 
   glCompressedTexImage2D: function(target, level, internalformat, width, height, border, imageSize, data) {
+    GL.ensureCompression();
     if (data) {
       data = {{{ makeHEAPView('U8', 'data', 'data+imageSize') }}};
     } else {
@@ -283,6 +294,7 @@ var LibraryGL = {
   },
 
   glCompressedTexSubImage2D: function(target, level, xoffset, yoffset, width, height, format, imageSize, data) {
+    GL.ensureCompression();
     if (data) {
       data = {{{ makeHEAPView('U8', 'data', 'data+imageSize') }}};
     } else {
@@ -947,7 +959,7 @@ var LibraryGL = {
       _glGetString = function(name_) {
         switch(name_) {
           case 0x1F03 /* GL_EXTENSIONS */: // Add various extensions that we can support
-            return allocate(intArrayFromString(Module.ctx.getSupportedExtensions().join(' ') + ' GL_EXT_texture_env_combine GL_ARB_texture_env_crossbar GL_ATI_texture_env_combine3 GL_NV_texture_env_combine4 GL_EXT_texture_env_dot3 GL_ARB_multitexture GL_ARB_vertex_buffer_object GL_EXT_framebuffer_object GL_ARB_vertex_program GL_ARB_fragment_program GL_ARB_shading_language_100 GL_ARB_shader_objects GL_ARB_vertex_shader GL_ARB_fragment_shader GL_ARB_texture_cube_map GL_EXT_draw_range_elements'), 'i8', ALLOC_NORMAL);
+            return allocate(intArrayFromString(Module.ctx.getSupportedExtensions().join(' ') + ' GL_EXT_texture_env_combine GL_ARB_texture_env_crossbar GL_ATI_texture_env_combine3 GL_NV_texture_env_combine4 GL_EXT_texture_env_dot3 GL_ARB_multitexture GL_ARB_vertex_buffer_object GL_EXT_framebuffer_object GL_ARB_vertex_program GL_ARB_fragment_program GL_ARB_shading_language_100 GL_ARB_shader_objects GL_ARB_vertex_shader GL_ARB_fragment_shader GL_ARB_texture_cube_map GL_EXT_draw_range_elements GL_ARB_texture_compression GL_EXT_texture_compression_s3tc'), 'i8', ALLOC_NORMAL);
         }
         return glGetString(name_);
       };