Work around CopyTexImage2D issue on Intel Mac OSX 10.12

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 13359 matching lines @@
             GetBoundReadFramebufferServiceId(),
             GetBoundReadFramebufferInternalFormat());
       } else {
         glCopyTexSubImage2D(target, level, destX, destY, copyX, copyY,
                             copyWidth, copyHeight);
       }
     }
   } else {
     GLenum final_internal_format = TextureManager::AdjustTexInternalFormat(
         feature_info_.get(), internal_format);
+    if (workarounds().init_two_cube_map_levels_before_copyteximage &&
+        texture->target() == GL_TEXTURE_CUBE_MAP &&
+        target != GL_TEXTURE_CUBE_MAP_POSITIVE_X) {
+      for (int i = 0; i < 2; ++i) {
+        TextureManager::DoTexImageArguments args = {
+          target, i, final_internal_format, 1, 1, 1, border,
+          format, type, nullptr, 1, 0,
+          TextureManager::DoTexImageArguments::kTexImage2D };
+        texture_manager()->WorkaroundCopyTexImageCubeMap(&texture_state_,

[Zhenyao Mo, 2016/10/11 03:10:18]

Here is my question: 

WorkaroundCopyTexImageCubeMap() call TextureManager::DoTexImage(), with
internal_format (LUMINANCE_ALPHA) already correctly mapped to
final_internal_format (RG), but format is still LUMINANCE_ALPHA.

That's why I don't understand how DoTexImage() could succeed? Or is there a
place format is also mapped and I missed it? 

[qiankun, 2016/10/11 03:18:19]

In TextureManager::DoTexImage, format is translated (i.e.
AdjustTexFormat(feature_info_.get(), args.format)) when calling glTexImage2D so
DoTexImage could succeed.
See:
https://cs.chromium.org/chromium/src/gpu/command_buffer/service/texture_manag...

+            &state_, &framebuffer_state_, texture_ref, func_name, args);
+      }
+    }
 
     // The service id and target of the texture attached to READ_FRAMEBUFFER.
     GLuint source_texture_service_id = 0;
     GLenum source_texture_target = 0;
     uint32_t channels_exist = GLES2Util::GetChannelsForFormat(read_format);
     bool use_workaround = NeedsCopyTextureImageWorkaround(
         final_internal_format, channels_exist, &source_texture_service_id,
         &source_texture_target);
     if (requires_luma_blit) {
       copy_tex_image_blit_->DoCopyTexImage2DToLUMACompatibilityTexture(
@@ skipping 35 matching lines @@
       glCopyTexImage2D(dest_texture_target, level, final_internal_format, 0, 0,
                        copyWidth, copyHeight, 0);
 
       // Rebind source texture.
       glFramebufferTexture2DEXT(framebuffer_target, GL_COLOR_ATTACHMENT0,
                                 source_texture_target,
                                 source_texture_service_id, 0);
 
       glDeleteTextures(1, &temp_texture);
     } else {
-      if (workarounds().do_teximage_before_copyteximage_to_cube_map &&
+      if (workarounds().init_one_cube_map_level_before_copyteximage &&
           texture->target() == GL_TEXTURE_CUBE_MAP &&
           target != GL_TEXTURE_CUBE_MAP_POSITIVE_X) {
         TextureManager::DoTexImageArguments args = {
           target, level, final_internal_format, width, height, 1, border,
           format, type, nullptr, pixels_size, 0,
           TextureManager::DoTexImageArguments::kTexImage2D };
         texture_manager()->WorkaroundCopyTexImageCubeMap(&texture_state_,
             &state_, &framebuffer_state_, texture_ref, func_name, args);
       }
       glCopyTexImage2D(target, level, final_internal_format, copyX, copyY,
@@ skipping 4799 matching lines @@
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "base/macros.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu