Force CUBE_MAP_POSITIVE_X texture allocation before CopyTexImage2D on Intel Mac

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index e2bd8d8f0f5922b42fe5f2ed20d532429b35e77b..d293c0af5430e2c2d30cde09805aafad9d92995f 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -13290,6 +13290,14 @@ void GLES2DecoderImpl::DoCopyTexImage2D(
 
       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);
     }