Update CopyTexImage2D to do internal format validation in ES3

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 <stdio.h>
 
 #include <algorithm>
 #include <cmath>
@@ skipping 1549 matching lines @@
   bool SetCapabilityState(GLenum cap, bool enabled);
 
   // Check that the currently bound framebuffers are valid.
   // Generates GL error if not.
   bool CheckBoundFramebuffersValid(const char* func_name);
 
   // Check that the currently bound read framebuffer has a color image
   // attached. Generates GL error if not.
   bool CheckBoundReadFramebufferColorAttachment(const char* func_name);
 
+  // Get the value of GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING for the
+  // framebuffer attachment corresponding to the read buffer.
+  GLint GetReadFramebufferAttachmentColorEncoding();
+
   // Check that the currently bound read framebuffer's color image
   // isn't the target texture of the glCopyTex{Sub}Image2D.
   bool FormsTextureCopyingFeedbackLoop(TextureRef* texture, GLint level);
 
   // Check if a framebuffer meets our requirements.
   bool CheckFramebufferValid(
       Framebuffer* framebuffer,
       GLenum target,
       const char* func_name);
 
@@ skipping 2432 matching lines @@
   if (!framebuffer)
     return true;
   if (framebuffer->GetAttachment(GL_COLOR_ATTACHMENT0) == NULL) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION, func_name, "no color image attached");
     return false;
   }
   return true;
 }
 
+GLint GLES2DecoderImpl::GetReadFramebufferAttachmentColorEncoding() {
+  GLenum target = features().chromium_framebuffer_multisample ?
+      GL_READ_FRAMEBUFFER_EXT : GL_FRAMEBUFFER_EXT;
+  GLint v = GL_NONE;
+  glGetFramebufferAttachmentParameterivEXT(
+      target, GL_COLOR_ATTACHMENT0,
+      GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING, &v);
+  return v;
+}
+
 bool GLES2DecoderImpl::FormsTextureCopyingFeedbackLoop(
     TextureRef* texture, GLint level) {
   Framebuffer* framebuffer = features().chromium_framebuffer_multisample ?
       framebuffer_state_.bound_read_framebuffer.get() :
       framebuffer_state_.bound_draw_framebuffer.get();
   if (!framebuffer)
     return false;
   const Framebuffer::Attachment* attachment = framebuffer->GetAttachment(
       GL_COLOR_ATTACHMENT0);
   if (!attachment)
@@ skipping 6964 matching lines @@
   GLenum read_format = GetBoundReadFrameBufferInternalFormat();
   uint32 channels_exist = GLES2Util::GetChannelsForFormat(read_format);
   uint32 channels_needed = GLES2Util::GetChannelsForFormat(internal_format);
 
   if ((channels_needed & channels_exist) != channels_needed) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION, "glCopyTexImage2D", "incompatible format");
     return;
   }
 
+  if (feature_info_->IsES3Enabled()) {
+    GLint color_encoding = GetReadFramebufferAttachmentColorEncoding();
+    if ((GL_LINEAR == color_encoding &&
+         GLES2Util::IsSRGBFormat(internal_format)) ||

[Zhenyao Mo, 2015/10/13 01:22:49]

One optimization is, instead of asking IsSRGBFormat, you can have a function
called GetColorEncodingFromInternalFormat().  Then you don't even have to call
the gl function, you can just infer from read_format.  Also, you will not need
to call IsSRGBFormat() twice here, you can just do if (color_endoding !=
GetReadFramebufferAttachmentColorEncoding())

Just an idea.

[qiankun, 2015/10/13 14:28:01]

Thanks for this suggestion! I implemented this optimization.

+        (GL_SRGB == color_encoding &&
+         !GLES2Util::IsSRGBFormat(internal_format)) ||
+        GLES2Util::IsFloatFormat(internal_format) ||
+        (GLES2Util::IsSignedIntegerFormat(internal_format) !=
+         GLES2Util::IsSignedIntegerFormat(read_format)) ||
+        (GLES2Util::IsUnsignedIntegerFormat(internal_format) !=
+         GLES2Util::IsUnsignedIntegerFormat(read_format))) {
+      LOCAL_SET_GL_ERROR(
+          GL_INVALID_OPERATION, "glCopyTexImage2D", "incompatible format");
+      return;
+    }
+  }
+
   if ((channels_needed & (GLES2Util::kDepth | GLES2Util::kStencil)) != 0) {
     LOCAL_SET_GL_ERROR(
         GL_INVALID_OPERATION,
         "glCopyTexImage2D", "can not be used with depth or stencil textures");
     return;
   }
 
   uint32 pixels_size = 0;
   GLenum format = ExtractFormatFromStorageFormat(internal_format);
   GLenum type = ExtractTypeFromStorageFormat(internal_format);
@@ skipping 4050 matching lines @@
   return error::kNoError;
 }
 
 // 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 "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu