command_buffer: Implement EXT_blend_func_extended

gpu/command_buffer/service/feature_info.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/feature_info.h"
 
 #include <set>
 #include <vector>
 
 #include "base/command_line.h"
@@ skipping 152 matching lines @@
       is_swiftshader(false),
       angle_texture_usage(false),
       ext_texture_storage(false),
       chromium_path_rendering(false),
       blend_equation_advanced(false),
       blend_equation_advanced_coherent(false),
       ext_texture_rg(false),
       chromium_image_ycbcr_422(false),
       enable_subscribe_uniform(false),
       emulate_primitive_restart_fixed_index(false),
-      ext_render_buffer_format_bgra8888(false) {}
+      ext_render_buffer_format_bgra8888(false),
+      ext_blend_func_extended(false) {}
 
 FeatureInfo::Workarounds::Workarounds() :
 #define GPU_OP(type, name) name(false),
     GPU_DRIVER_BUG_WORKAROUNDS(GPU_OP)
 #undef GPU_OP
     max_texture_size(0),
     max_cube_map_texture_size(0),
     max_fragment_uniform_vectors(0),
     max_varying_vectors(0),
     max_vertex_uniform_vectors(0),
@@ skipping 875 matching lines @@
     validators_.texture_internal_format.AddValue(GL_R8_EXT);
     validators_.texture_internal_format.AddValue(GL_RG_EXT);
     validators_.texture_internal_format.AddValue(GL_RG8_EXT);
     validators_.read_pixel_format.AddValue(GL_RED_EXT);
     validators_.read_pixel_format.AddValue(GL_RG_EXT);
     validators_.render_buffer_format.AddValue(GL_R8_EXT);
     validators_.render_buffer_format.AddValue(GL_RG8_EXT);
   }
   UMA_HISTOGRAM_BOOLEAN("GPU.TextureRG", feature_flags_.ext_texture_rg);
 
+  if (gl_version_info_->IsAtLeastGL(3, 3) ||
+      (gl_version_info_->IsAtLeastGL(3, 2) &&
+       extensions.Contains("GL_ARB_blend_func_extended")) ||
+      (gl_version_info_->is_es &&
+       extensions.Contains("GL_EXT_blend_func_extended"))) {
+    feature_flags_.ext_blend_func_extended = true;
+    AddExtensionString("GL_EXT_blend_func_extended");
+
+    // NOTE: SRC_ALPHA_SATURATE is valid for ES2 src blend factor.
+    // SRC_ALPHA_SATURATE is valid for ES3 src and dst blend factor.
+    validators_.dst_blend_factor.AddValue(GL_SRC_ALPHA_SATURATE_EXT);

[Mark Kilgard, 2015/08/28 19:53:24]

good, this is actually explicitly documented in the EXT_blend_func_extended
extension and makes blend functionality more consistent with ES 3.x and big
OpenGL

In practical terms, nobody is going to care that SRC_ALPHA_SATURATE is allowed
on a dest function, but it makes everything more othogonal, particularly the
source and destination error checks are identical

+
+    validators_.src_blend_factor.AddValue(GL_SRC1_ALPHA_EXT);
+    validators_.dst_blend_factor.AddValue(GL_SRC1_ALPHA_EXT);
+    validators_.src_blend_factor.AddValue(GL_SRC1_COLOR_EXT);
+    validators_.dst_blend_factor.AddValue(GL_SRC1_COLOR_EXT);
+    validators_.src_blend_factor.AddValue(GL_ONE_MINUS_SRC1_COLOR_EXT);
+    validators_.dst_blend_factor.AddValue(GL_ONE_MINUS_SRC1_COLOR_EXT);
+    validators_.src_blend_factor.AddValue(GL_ONE_MINUS_SRC1_ALPHA_EXT);
+    validators_.dst_blend_factor.AddValue(GL_ONE_MINUS_SRC1_ALPHA_EXT);
+    validators_.g_l_state.AddValue(GL_MAX_DUAL_SOURCE_DRAW_BUFFERS_EXT);
+  }
+
 #if !defined(OS_MACOSX)
   if (workarounds_.ignore_egl_sync_failures) {
     gfx::GLFenceEGL::SetIgnoreFailures();
   }
 #endif
 
   if (workarounds_.avoid_egl_image_target_texture_reuse) {
     TextureDefinition::AvoidEGLTargetTextureReuse();
   }
 
@@ skipping 86 matching lines @@
   if (pos == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 FeatureInfo::~FeatureInfo() {
 }
 
 }  // namespace gles2
 }  // namespace gpu