Implement support for KHR_blend_equation_advanced

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 288 matching lines @@
         fTwoSidedStencilSupport = (ctxInfo.version() >= GR_GL_VER(2,0));
         // supported on GL 1.4 and higher or by extension
         fStencilWrapOpsSupport = (ctxInfo.version() >= GR_GL_VER(1,4)) ||
                                   ctxInfo.hasExtension("GL_EXT_stencil_wrap");
     } else {
         // ES 2 has two sided stencil and stencil wrap
         fTwoSidedStencilSupport = true;
         fStencilWrapOpsSupport = true;
     }
 
+    // GL_KHR_blend_equation_advanced is a proper subset of GL_NV_blend_equation_advanced, with all
+    // the same enums, but we still check for the NV variants to support legacy drivers that didn't
+    // export the KHR extension yet.
+    if (ctxInfo.hasExtension("GL_KHR_blend_equation_advanced_coherent") ||
+        ctxInfo.hasExtension("GL_NV_blend_equation_advanced_coherent")) {
+        fBlendEquationSupport = kAdvancedCoherent_BlendEquationSupport;
+    } else if (ctxInfo.hasExtension("GL_KHR_blend_equation_advanced") ||
+               ctxInfo.hasExtension("GL_NV_blend_equation_advanced")) {
+        fBlendEquationSupport = kAdvanced_BlendEquationSupport;
+    } else {
+        fBlendEquationSupport = kBasic_BlendEquationSupport;
+    }
+
     if (kGL_GrGLStandard == standard) {
         fMapBufferFlags = kCanMap_MapFlag; // we require VBO support and the desktop VBO
                                             // extension includes glMapBuffer.
         if (version >= GR_GL_VER(3, 0) || ctxInfo.hasExtension("GL_ARB_map_buffer_range")) {
             fMapBufferFlags |= kSubset_MapFlag;
             fMapBufferType = kMapBufferRange_MapBufferType;
         } else {
             fMapBufferType = kMapBuffer_MapBufferType;
         }
     } else {
@@ skipping 739 matching lines @@
     r.appendf("Two Format Limit: %s\n", (fTwoFormatLimit ? "YES": "NO"));
     r.appendf("Fragment coord conventions support: %s\n",
              (fFragCoordsConventionSupport ? "YES": "NO"));
     r.appendf("Vertex array object support: %s\n", (fVertexArrayObjectSupport ? "YES": "NO"));
     r.appendf("Use non-VBO for dynamic data: %s\n",
              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
     r.appendf("Full screen clear is free: %s\n", (fFullClearIsFree ? "YES" : "NO"));
     r.appendf("Drops tile on zero divide: %s\n", (fDropsTileOnZeroDivide ? "YES" : "NO"));
     return r;
 }