command_buffer: Implement EXT_blend_func_extended

gpu/command_buffer/service/program_manager.cc

Index: gpu/command_buffer/service/program_manager.cc
diff --git a/gpu/command_buffer/service/program_manager.cc b/gpu/command_buffer/service/program_manager.cc
index aba284b86cbe0aae2ecd589ef91cbc9f8482e60b..77a1d9119f4673b8936ba4202e1ff80c23270e1f 100644
--- a/gpu/command_buffer/service/program_manager.cc
+++ b/gpu/command_buffer/service/program_manager.cc
@@ -26,6 +26,7 @@
 #include "gpu/command_buffer/service/program_cache.h"
 #include "gpu/command_buffer/service/shader_manager.h"
 #include "third_party/re2/re2/re2.h"
+#include "ui/gl/gl_version_info.h"
 
 using base::TimeDelta;
 using base::TimeTicks;
@@ -630,6 +631,44 @@ void Program::ExecuteBindAttribLocationCalls() {
   }
 }
 
+void Program::ExecuteBindFragDataLocationIndexedCalls() {
+  Shader* fragment_shader =
+      attached_shaders_[ShaderTypeToIndex(GL_FRAGMENT_SHADER)].get();
+  if (fragment_shader->shader_version() == 100 &&
+      !feature_info().gl_version_info().is_es) {
+    // Map gl_SecondaryFragColorEXT / gl_SecondaryFragDataEXT of
+    // EXT_blend_func_extended to real
+    // color indexes, if underlying context is not ES.
+
+    for (auto const& output_var : fragment_shader->output_variable_list()) {
+      const std::string& name = output_var.mappedName;
+      if (name == "gl_FragColor") {
+        DCHECK(output_var.location == -1);
+        DCHECK(output_var.arraySize == 0u);
+        // We leave these unbound by not giving a binding name. The driver will
+        // bind this.
+      } else if (name == "gl_FragData") {
+        DCHECK(output_var.location == -1);
+        DCHECK(output_var.arraySize != 0u);
+        // We leave these unbound by not giving a binding name. The driver will
+        // bind this.
+      } else if (name == "gl_SecondaryFragColorEXT") {
+        DCHECK(feature_info().feature_flags().ext_blend_func_extended);
+        DCHECK(output_var.location == -1);
+        DCHECK(output_var.arraySize == 0u);
+        glBindFragDataLocationIndexed(service_id_, 0, 1,
+                                      "angle_SecondaryFragColor");
+      } else if (name == "gl_SecondaryFragDataEXT") {
+        DCHECK(feature_info().feature_flags().ext_blend_func_extended);
+        DCHECK(output_var.location == -1);
+        DCHECK(output_var.arraySize != 0u);
+        glBindFragDataLocationIndexed(service_id_, 0, 1,
+                                      "angle_SecondaryFragData");
+      }
+    }

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

agree with all this

the point being non-ES 2.0 shading languages don't have the gl_*Frag* variables
for this.  But ES 2.0 GLSL didn't have the layout sophistication of modern GLSL
dialects.

Good bridging.

+  }
+}
+
 bool Program::Link(ShaderManager* manager,
                    Program::VaryingsPackingOption varyings_packing_option,
                    const ShaderCacheCallback& shader_callback) {
@@ -714,6 +753,8 @@ bool Program::Link(ShaderManager* manager,
     }
 
     ExecuteBindAttribLocationCalls();
+    ExecuteBindFragDataLocationIndexedCalls();
+
     before_time = TimeTicks::Now();
     if (cache && gfx::g_driver_gl.ext.b_GL_ARB_get_program_binary) {
       glProgramParameteri(service_id(),
@@ -1823,6 +1864,26 @@ bool Program::GetUniformsES3(CommonDecoder::Bucket* bucket) const {
   return true;
 }
 
+GLint Program::GetFragDataLocation(const std::string& original_name) const {
+  DCHECK(IsValid());
+  Shader* shader =
+      attached_shaders_[ShaderTypeToIndex(GL_FRAGMENT_SHADER)].get();
+  if (!shader->GetOutputVariableInfo(original_name)) {
+    return -1;
+  }
+  return glGetFragDataLocation(service_id_, original_name.c_str());
+}
+
+GLint Program::GetFragDataIndex(const std::string& original_name) const {
+  DCHECK(IsValid());
+  Shader* shader =
+      attached_shaders_[ShaderTypeToIndex(GL_FRAGMENT_SHADER)].get();
+  if (!shader->GetOutputVariableInfo(original_name)) {
+    return -1;
+  }
+  return glGetFragDataIndex(service_id_, original_name.c_str());
+}
+
 void Program::TransformFeedbackVaryings(GLsizei count,
                                         const char* const* varyings,
                                         GLenum buffer_mode) {
@@ -1845,11 +1906,13 @@ Program::~Program() {
 
 ProgramManager::ProgramManager(ProgramCache* program_cache,
                                uint32 max_varying_vectors,
+                               uint32 max_dual_source_draw_buffers,
                                FeatureInfo* feature_info)
     : program_count_(0),
       have_context_(true),
       program_cache_(program_cache),
       max_varying_vectors_(max_varying_vectors),
+      max_dual_source_draw_buffers_(max_dual_source_draw_buffers),
       feature_info_(feature_info) {}
 
 ProgramManager::~ProgramManager() {