refactor gl compression ext handling

1 files changed, 12 insertions, 9 deletions

diff --git a/src/library_gl.js b/src/library_gl.js
index 5cf8f8d3..593bc1d8 100644
--- a/src/library_gl.js
+++ b/src/library_gl.js
@@ -23,7 +23,7 @@ var LibraryGL = {
     unpackAlignment: 4, // default alignment is 4 bytes
 
     init: function() {
-      Browser.moduleContextCreatedCallbacks.push(GL.initCompression);
+      Browser.moduleContextCreatedCallbacks.push(GL.initExtensions);
     },
 
     // Linear lookup in one of the tables (buffers, programs, etc.). TODO: consider using a weakmap to make this faster, if it matters
@@ -107,14 +107,13 @@ var LibraryGL = {
                ((height - 1) * alignedRowSize + plainRowSize);
     },
 
-    initCompression: function() {
-      if (GL.initCompression.done) return;
-      GL.initCompression.done = true;
+    initExtensions: function() {
+      if (GL.initExtensions.done) return;
+      GL.initExtensions.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');  
-      if (!ext) Module.printErr('Failed to get texture compression WebGL extension, if compressed textures are used they will fail');
+      GL.compressionExt = Module.ctx.getExtension('WEBGL_compressed_texture_s3tc') ||
+                          Module.ctx.getExtension('MOZ_WEBGL_compressed_texture_s3tc') ||
+                          Module.ctx.getExtension('WEBKIT_WEBGL_compressed_texture_s3tc');
     }
   },
 
@@ -289,6 +288,7 @@ var LibraryGL = {
   },
 
   glCompressedTexImage2D: function(target, level, internalformat, width, height, border, imageSize, data) {
+    assert(GL.compressionExt);
     if (data) {
       data = {{{ makeHEAPView('U8', 'data', 'data+imageSize') }}};
     } else {
@@ -298,6 +298,7 @@ var LibraryGL = {
   },
 
   glCompressedTexSubImage2D: function(target, level, xoffset, yoffset, width, height, format, imageSize, data) {
+    assert(GL.compressionExt);
     if (data) {
       data = {{{ makeHEAPView('U8', 'data', 'data+imageSize') }}};
     } else {
@@ -991,7 +992,9 @@ 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 GL_ARB_texture_compression GL_EXT_texture_compression_s3tc'), '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.compressionExt ? ' GL_ARB_texture_compression GL_EXT_texture_compression_s3tc' : '')), 'i8', ALLOC_NORMAL);
         }
         return glGetString(name_);
       };