Fix a bug in drawBuffers optimization.

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 1319 matching lines @@
 
   // Checks if a draw buffer's format and its corresponding fragment shader
   // output's type are compatible, i.e., a signed integer typed variable is
   // incompatible with a float or unsigned integer buffer.
   // If incompaticle, generates an INVALID_OPERATION to avoid undefined buffer
   // contents and return false.
   // Otherwise, filter out the draw buffers that are not written to but are not
   // NONE through DrawBuffers, to be on the safe side. Return true.
   bool ValidateAndAdjustDrawBuffers(const char* function_name);
 
+  // Filter out the draw buffers that have no images attached but are not NONE
+  // through DrawBuffers, to be on the safe side.
+  void AdjustDrawBuffers();
+
   // Checks if all active uniform blocks in the current program are backed by
   // a buffer of sufficient size.
   // If not, generates an INVALID_OPERATION to avoid undefined behavior in
   // shader execution and return false.
   bool ValidateUniformBlockBackings(const char* function_name);
 
   // Checks if |api_type| is valid for the given uniform
   // If the api type is not valid generates the appropriate GL
   // error. Returns true if |api_type| is valid for the uniform
   bool CheckUniformForApiType(const Program::UniformInfo* info,
@@ skipping 5930 matching lines @@
     }
     if (mask & GL_COLOR_BUFFER_BIT) {
       Framebuffer* framebuffer =
           framebuffer_state_.bound_draw_framebuffer.get();
       if (framebuffer && framebuffer->ContainsActiveIntegerAttachments()) {
         LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name,
             "can't be called on integer buffers");
         return error::kNoError;
       }
     }
+    AdjustDrawBuffers();
     glClear(mask);
   }
   return error::kNoError;
 }
 
 void GLES2DecoderImpl::DoClearBufferiv(GLenum buffer,
                                        GLint drawbuffer,
                                        const volatile GLint* value) {
   const char* func_name = "glClearBufferiv";
   if (!CheckBoundDrawFramebufferValid(func_name))
@@ skipping 1539 matching lines @@
       state_.current_program->fragment_output_written_mask();
   if (!framebuffer->ValidateAndAdjustDrawBuffers(
       fragment_output_type_mask, fragment_output_written_mask)) {
       LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name,
           "buffer format and fragment output variable type incompatible");
       return false;
   }
   return true;
 }
 
+void GLES2DecoderImpl::AdjustDrawBuffers() {
+  if (!SupportsDrawBuffers()) {
+    return;
+  }
+  Framebuffer* framebuffer = framebuffer_state_.bound_draw_framebuffer.get();
+  if (framebuffer) {
+    framebuffer->AdjustDrawBuffers();
+  }
+}
+
 bool GLES2DecoderImpl::ValidateUniformBlockBackings(const char* func_name) {
   DCHECK(feature_info_->IsWebGL2OrES3Context());
   if (!state_.current_program.get())
     return true;
   int32_t max_index = -1;
   for (auto info : state_.current_program->uniform_block_size_info()) {
     int32_t index = static_cast<int32_t>(info.binding);
     if (index > max_index)
       max_index = index;
   }
@@ skipping 10259 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