Re-land: gpu: Add GL_TEXTURE_RECTANGLE_ARB support to CopyTexSubImage2D optimization of CopyTexture.

gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc

Index: gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
index 00f510db2832f23462cd1217cb7763a4477f778c..33ecbd662e9ceb846107ae77d1df7434e8a08032 100644
--- a/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
+++ b/gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include "base/basictypes.h"
+#include "gpu/command_buffer/common/gles2_cmd_utils.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
@@ -362,18 +363,25 @@ void CopyTextureCHROMIUMResourceManager::DoCopyTexture(
     bool premultiply_alpha,
     bool unpremultiply_alpha) {
   bool premultiply_alpha_change = premultiply_alpha ^ unpremultiply_alpha;
+  uint32_t source_channels = gles2::GLES2Util::GetChannelsForFormat(
+      source_internal_format);
+  uint32_t dest_channels = gles2::GLES2Util::GetChannelsForFormat(
+      dest_internal_format);
   // GL_INVALID_OPERATION is generated if the currently bound framebuffer's
   // format does not contain a superset of the components required by the base
   // format of internalformat.
   // https://www.khronos.org/opengles/sdk/docs/man/xhtml/glCopyTexImage2D.xml
   bool source_format_contain_superset_of_dest_format =
-      (source_internal_format == dest_internal_format &&
-       source_internal_format != GL_BGRA_EXT) ||
-      (source_internal_format == GL_RGBA && dest_internal_format == GL_RGB);
-  // GL_TEXTURE_RECTANGLE_ARB on FBO is supported by OpenGL, not GLES2,
-  // so restrict this to GL_TEXTURE_2D.
-  if (source_target == GL_TEXTURE_2D && !flip_y && !premultiply_alpha_change &&
-      source_format_contain_superset_of_dest_format) {
+      (source_channels & dest_channels) == dest_channels;
+  // Note: GL_TEXTURE_RECTANGLE_ARB is only available if supported on FBOs.
+  bool valid_source_target = source_target == GL_TEXTURE_2D ||
+                             source_target == GL_TEXTURE_RECTANGLE_ARB;
+  bool valid_dest_internal_format = dest_internal_format == GL_ALPHA ||
+                                    dest_internal_format == GL_RGB ||
+                                    dest_internal_format == GL_RGBA;
+  if (valid_source_target && !flip_y && !premultiply_alpha_change &&
+      source_format_contain_superset_of_dest_format &&
+      valid_dest_internal_format) {
     DoCopyTexImage2D(decoder,
                      source_target,
                      source_id,
@@ -412,18 +420,25 @@ void CopyTextureCHROMIUMResourceManager::DoCopySubTexture(
     bool premultiply_alpha,
     bool unpremultiply_alpha) {
   bool premultiply_alpha_change = premultiply_alpha ^ unpremultiply_alpha;
+  uint32_t source_channels = gles2::GLES2Util::GetChannelsForFormat(
+      source_internal_format);
+  uint32_t dest_channels = gles2::GLES2Util::GetChannelsForFormat(
+      dest_internal_format);
   // GL_INVALID_OPERATION is generated if the currently bound framebuffer's
   // format does not contain a superset of the components required by the base
   // format of internalformat.
   // https://www.khronos.org/opengles/sdk/docs/man/xhtml/glCopyTexImage2D.xml
   bool source_format_contain_superset_of_dest_format =
-      (source_internal_format == dest_internal_format &&
-       source_internal_format != GL_BGRA_EXT) ||
-      (source_internal_format == GL_RGBA && dest_internal_format == GL_RGB);
-  // GL_TEXTURE_RECTANGLE_ARB on FBO is supported by OpenGL, not GLES2,
-  // so restrict this to GL_TEXTURE_2D.
-  if (source_target == GL_TEXTURE_2D && !flip_y && !premultiply_alpha_change &&
-      source_format_contain_superset_of_dest_format) {
+      (source_channels & dest_channels) == dest_channels;
+  // Note: GL_TEXTURE_RECTANGLE_ARB is only available if supported on FBOs.
+  bool valid_source_target = source_target == GL_TEXTURE_2D ||
+                             source_target == GL_TEXTURE_RECTANGLE_ARB;
+  bool valid_dest_internal_format = dest_internal_format == GL_ALPHA ||
+                                    dest_internal_format == GL_RGB ||
+                                    dest_internal_format == GL_RGBA;
+  if (valid_source_target && !flip_y && !premultiply_alpha_change &&
+      source_format_contain_superset_of_dest_format &&
+      valid_dest_internal_format) {
     DoCopyTexSubImage2D(decoder, source_target, source_id, dest_id, xoffset,
                         yoffset, x, y, width, height, framebuffer_);
     return;