Implement support for dual source blending in ES

src/gpu/gl/GrGLCaps.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLCaps.h"
 
@@ skipping 253 matching lines @@
     else {
         fES2CompatibilitySupport = true;
     }
 
     if (kGL_GrGLStandard == standard) {
         fMultisampleDisableSupport = true;
     } else {
         fMultisampleDisableSupport = false;
     }
 
-    if (kGL_GrGLStandard == standard && version >= GR_GL_VER(3, 0)) {
-        fBindFragDataLocationSupport = true;
+    if (kGL_GrGLStandard == standard) {
+        if (version >= GR_GL_VER(3, 0)) {
+            fBindFragDataLocationSupport = true;
+        }
+    } else {
+        if (version >= GR_GL_VER(3, 0) && ctxInfo.hasExtension("GL_EXT_blend_func_extended")) {
+            fBindFragDataLocationSupport = true;
+        }
     }
 
     /**************************************************************************
     * GrShaderCaps fields
     **************************************************************************/
 
     glslCaps->fPathRenderingSupport = this->hasPathRenderingSupport(ctxInfo, gli);
 
     // For now these two are equivalent but we could have dst read in shader via some other method
     glslCaps->fDstReadInShaderSupport = glslCaps->fFBFetchSupport;
 
     // Enable supported shader-related caps
     if (kGL_GrGLStandard == standard) {
         glslCaps->fDualSourceBlendingSupport = (ctxInfo.version() >= GR_GL_VER(3, 3) ||
             ctxInfo.hasExtension("GL_ARB_blend_func_extended")) &&
             GrGLSLSupportsNamedFragmentShaderOutputs(ctxInfo.glslGeneration());
         glslCaps->fShaderDerivativeSupport = true;
         // we don't support GL_ARB_geometry_shader4, just GL 3.2+ GS
         glslCaps->fGeometryShaderSupport = ctxInfo.version() >= GR_GL_VER(3, 2) &&
             ctxInfo.glslGeneration() >= k150_GrGLSLGeneration;
     }
     else {
+        glslCaps->fDualSourceBlendingSupport = ctxInfo.hasExtension("GL_EXT_blend_func_extended");
+
         glslCaps->fShaderDerivativeSupport = ctxInfo.version() >= GR_GL_VER(3, 0) ||
             ctxInfo.hasExtension("GL_OES_standard_derivatives");
     }
 
     // We need dual source blending and the ability to disable multisample in order to support mixed
     // samples in every corner case.
     if (fMultisampleDisableSupport && glslCaps->fDualSourceBlendingSupport) {
         // We understand "mixed samples" to mean the collective capability of 3 different extensions
         glslCaps->fMixedSamplesSupport =
             ctxInfo.hasExtension("GL_NV_framebuffer_mixed_samples") &&
@@ skipping 893 matching lines @@
         for (int p = 0; p < kGrSLPrecisionCount; ++p) {
             glslCaps->fFloatPrecisions[kGeometry_GrShaderType][p] = 
                                                glslCaps->fFloatPrecisions[kVertex_GrShaderType][p];
         }
     }
 }