Command buffer: CopyTexSubImage3D should clear the 3D texture if it is uncleared

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 13284 matching lines @@
     return;
   }
 
   if (FormsTextureCopyingFeedbackLoop(texture_ref, level, zoffset)) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,
         func_name, "source and destination textures are the same");
     return;
   }
 
+  // For 3D textures, we always clear the entire texture. See the code in
+  // TextureManager::ValidateAndDoTexSubImage for TexSubImage3D.
+  if (!texture->IsLevelCleared(target, level)) {
+    texture_manager()->ClearTextureLevel(this, texture_ref, target, level);
+    DCHECK(texture->IsLevelCleared(target, level));
+  }
+
   // TODO(yunchao): Follow-up CLs are necessary. For instance:
   // 1. emulation of unsized formats in core profile
-  // 2. clear the 3d textures if it is uncleared.
-  // 3. out-of-bounds reading, etc.
+  // 2. out-of-bounds reading, etc.

[Zhenyao Mo, 2016/08/10 20:27:20]

Can you file a bug for this?  Comments in the code could easily get lost.

 
   glCopyTexSubImage3D(target, level, xoffset, yoffset, zoffset, x, y, width,
                       height);
 
   // This may be a slow command.  Exit command processing to allow for
   // context preemption and GPU watchdog checks.
   ExitCommandProcessingEarly();
 }
 
 error::Error GLES2DecoderImpl::HandleTexSubImage2D(uint32_t immediate_data_size,
@@ skipping 4439 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