gpu: Optimize and cleanup code used for CHROMIUM_copy_texture.

gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.h

 // 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.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_COPY_TEXTURE_CHROMIUM_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_COPY_TEXTURE_CHROMIUM_H_
 
 #include <vector>
 
 #include "base/containers/hash_tables.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/gpu_export.h"
 
 namespace gpu {
 namespace gles2 {
 
 class GLES2Decoder;
 
 }  // namespace gles2.
 
 // This class encapsulates the resources required to implement the
 // GL_CHROMIUM_copy_texture extension.  The copy operation is performed
-// via a blit to a framebuffer object.
+// via glCopyTexImage2D() or a blit to a framebuffer object.
+// The target of |dest_id| texture must be GL_TEXTURE_2D.
 class GPU_EXPORT CopyTextureCHROMIUMResourceManager {
  public:
   CopyTextureCHROMIUMResourceManager();
   ~CopyTextureCHROMIUMResourceManager();
 
   void Initialize(const gles2::GLES2Decoder* decoder);
   void Destroy();
 
-  void DoCopyTexture(const gles2::GLES2Decoder* decoder, GLenum source_target,
-                     GLenum dest_target, GLuint source_id, GLuint dest_id,
-                     GLint level, GLsizei width, GLsizei height,
-                     bool flip_y, bool premultiply_alpha,
+  void DoCopyTexture(const gles2::GLES2Decoder* decoder,
+                     GLenum source_target,
+                     GLuint source_id,
+                     GLuint dest_id,
+                     GLint level,
+                     GLenum internal_format,
+                     GLsizei width,
+                     GLsizei height,
+                     bool flip_y,
+                     bool premultiply_alpha,
                      bool unpremultiply_alpha);
 
   // This will apply a transform on the source texture before copying to
-  // destination texture.
+  // destination texture. |level| and |internal_format| are of |dest_id|
+  // texture. |internal_format| specifies the internal format of the texture.
+  // e.g. GL_RGBA, GL_RGB

[reveman, 2014/07/10 20:20:49]

nit: this applies to DoCopyTexture as well. maybe move the comment above to
DoCopyTexture and say something like "Same as DoCopyTexture but will apply a
transform..." in this comment instead. alternatively, you can probably add dest_
prefix to level/internal_format and just keep the comments as before this patch.
just make sure you add dest_ prefix to the .cc file too in that case.

[dshwang, 2014/07/10 22:08:22]

Thank you for detail suggestions. I chose the second option; dest_ prefix

   void DoCopyTextureWithTransform(const gles2::GLES2Decoder* decoder,
-                                  GLenum source_target, GLenum dest_target,
-                                  GLuint source_id, GLuint dest_id, GLint level,
-                                  GLsizei width, GLsizei height, bool flip_y,
+                                  GLenum source_target,
+                                  GLuint source_id,
+                                  GLuint dest_id,
+                                  GLint level,
+                                  GLenum internal_format,
+                                  GLsizei width,
+                                  GLsizei height,
+                                  bool flip_y,
                                   bool premultiply_alpha,
                                   bool unpremultiply_alpha,
                                   const GLfloat transform_matrix[16]);
 
   // The attributes used during invocation of the extension.
   static const GLuint kVertexPositionAttrib = 0;
 
  private:
   struct ProgramInfo {
     ProgramInfo()
@@ skipping 17 matching lines @@
   ProgramMap programs_;
   GLuint buffer_id_;
   GLuint framebuffer_;
 
   DISALLOW_COPY_AND_ASSIGN(CopyTextureCHROMIUMResourceManager);
 };
 
 }  // namespace gpu.
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_COPY_TEXTURE_CHROMIUM_H_