command_buffer: Implement EXT_blend_func_extended

gpu/command_buffer/service/feature_info.cc

Index: gpu/command_buffer/service/feature_info.cc
diff --git a/gpu/command_buffer/service/feature_info.cc b/gpu/command_buffer/service/feature_info.cc
index 766f7687d240255869a7cf88b5886e6907d38694..b4b9cc895748b2fab5d8a822d1475081918d8fd2 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -172,7 +172,8 @@ FeatureInfo::FeatureFlags::FeatureFlags()
       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),
@@ -222,7 +223,8 @@ void FeatureInfo::InitializeBasicState(const base::CommandLine* command_line) {
 
   // The shader translator is needed to translate from WebGL-conformant GLES SL
   // to normal GLES SL, enforce WebGL conformance, translate from GLES SL 1.0 to
-  // target context GLSL, etc.
+  // target context GLSL, implement emulation of OpenGL ES features on OpenGL,
+  // etc.
   // The flag here is for testing only.
   disable_shader_translator_ =
       command_line->HasSwitch(switches::kDisableGLSLTranslator);
@@ -1069,15 +1071,20 @@ void FeatureInfo::InitializeFeatures() {
     }
   }
 
+  bool has_opengl_program_interface_query =
+      gl_version_info_->IsAtLeastGL(4, 3) ||
+      extensions.Contains("GL_ARB_program_interface_query");
+
   if (enable_gl_path_rendering_switch_ &&
       !workarounds_.disable_gl_path_rendering &&
       extensions.Contains("GL_NV_path_rendering")) {
-    bool has_dsa = gl_version_info_->IsAtLeastGL(4, 5) ||
-                   extensions.Contains("GL_EXT_direct_state_access");
-    bool has_piq = gl_version_info_->IsAtLeastGL(4, 3) ||
-                   extensions.Contains("GL_ARB_program_interface_query");
+    bool has_opengl_direct_state_access =
+        gl_version_info_->IsAtLeastGL(4, 5) ||
+        extensions.Contains("GL_EXT_direct_state_access");
     if (gl_version_info_->IsAtLeastGLES(3, 1) ||
-        (gl_version_info_->IsAtLeastGL(3, 2) && has_dsa && has_piq)) {
+        (gl_version_info_->IsAtLeastGL(3, 2) &&
+         has_opengl_direct_state_access &&
+         has_opengl_program_interface_query)) {
       AddExtensionString("GL_CHROMIUM_path_rendering");
       feature_flags_.chromium_path_rendering = true;
       validators_.g_l_state.AddValue(GL_PATH_MODELVIEW_MATRIX_CHROMIUM);
@@ -1108,6 +1115,37 @@ void FeatureInfo::InitializeFeatures() {
   }
   UMA_HISTOGRAM_BOOLEAN("GPU.TextureRG", feature_flags_.ext_texture_rg);
 
+  bool has_opengl_dual_source_blending =
+      gl_version_info_->IsAtLeastGL(3, 3) ||
+      (gl_version_info_->IsAtLeastGL(3, 2) &&
+       extensions.Contains("GL_ARB_blend_func_extended"));
+  if ((gl_version_info_->IsAtLeastGL(3, 2) && has_opengl_dual_source_blending &&
+       has_opengl_program_interface_query && !disable_shader_translator_) ||
+      (gl_version_info_->IsAtLeastGLES(3, 1) &&
+       extensions.Contains("GL_EXT_blend_func_extended"))) {
+    // Note: to simplify the code, we do not expose EXT_blend_func_extended
+    // unless the service
+    // context supports program interface query. This means the theoretical ES
+    // 2.0 or ES 3.0
+    // implementation with EXT_blend_func_extended is not sufficient.
+    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);
+
+    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();