Force CUBE_MAP_POSITIVE_X texture allocation before CopyTexImage2D on Intel Mac

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 13272 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_texture_image_before_copy_texture_image &&
+          target == GL_TEXTURE_CUBE_MAP_NEGATIVE_X) {

[piman, 2016/09/19 20:33:13]

Is it /really/ only GL_TEXTURE_CUBE_MAP_NEGATIVE_X that is affected? Or is is
that maybe if the texture isn't cube complete - or maybe if
GL_TEXTURE_CUBE_MAP_POSITIVE_X specifically isn't defined?

This sounds similar to the workaround we have for TexImage2D - see logic about
'need_cube_map_workaround' in TextureManager::ValidateAndDoTexImage. Could we
reuse that logic?

[Ken Russell (switch to Gerrit), 2016/09/19 23:15:10]

+1 to piman's comments -- also, if a separate workaround is absolutely required,
please name it something more precise. Perhaps
"do_teximage_before_copyteximage_to_cube_map".

FYI, I think the needs_cube_map_workaround code may be buggy. I am planning to
eliminate the need for it at least for CopyTextureCHROMIUM by changing
CopyTextureCHROMIUM in http://crbug.com/612542 .

[qiankun, 2016/09/20 11:34:16]

Yes. They are similar. I used the same workaround as TexImage2D. Thanks for
pointing it.

+        for (int i = 0; i < 6; ++i) {
+          GLenum face = GL_TEXTURE_CUBE_MAP_POSITIVE_X + i;
+          glTexImage2D(face, level, final_internal_format,
+                       width, height, border, format, type, 0);

[piman, 2016/09/19 20:33:13]

What if those were already defined? This would lose the pixels.

[Ken Russell (switch to Gerrit), 2016/09/19 23:15:10]

+1. Also, have you verified that it's necessary to define all six faces and not
just GL_TEXTURE_CUBE_MAP_POSITIVE_X?

[qiankun, 2016/09/20 11:34:16]

Do initialization for uninitialized GL_TEXTURE_CUBE_MAP_POSITIVE_X texture now.

+        }
+      }
       glCopyTexImage2D(target, level, final_internal_format, copyX, copyY,
                        copyWidth, copyHeight, border);
     }
   }
   GLenum error = LOCAL_PEEK_GL_ERROR(func_name);
   if (error == GL_NO_ERROR) {
     texture_manager()->SetLevelInfo(texture_ref, target, level, internal_format,
                                     width, height, 1, border, format,
                                     type, gfx::Rect(width, height));
     texture->ApplyFormatWorkarounds(feature_info_.get());
@@ skipping 4691 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