Add support for GL_EXT_raster_multisample

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 405 matching lines @@
     fReuseScratchTextures = kARM_GrGLVendor != ctxInfo.vendor() &&
                             kQualcomm_GrGLVendor != ctxInfo.vendor();
 
 #if 0
     fReuseScratchBuffers = kARM_GrGLVendor != ctxInfo.vendor() &&
                            kQualcomm_GrGLVendor != ctxInfo.vendor();
 #endif
 
     // initFSAASupport() must have been called before this point
     if (GrGLCaps::kES_IMG_MsToTexture_MSFBOType == fMSFBOType) {
-        GR_GL_GetIntegerv(gli, GR_GL_MAX_SAMPLES_IMG, &fMaxColorSampleCount);
+        GR_GL_GetIntegerv(gli, GR_GL_MAX_SAMPLES_IMG, &fMaxStencilSampleCount);
     } else if (GrGLCaps::kNone_MSFBOType != fMSFBOType) {
-        GR_GL_GetIntegerv(gli, GR_GL_MAX_SAMPLES, &fMaxColorSampleCount);
+        GR_GL_GetIntegerv(gli, GR_GL_MAX_SAMPLES, &fMaxStencilSampleCount);
     }
-    fMaxStencilSampleCount = fMaxColorSampleCount;
+    // We only have a use for raster multisample if there is coverage modulation from mixed samples.
+    if (fUsesMixedSamples && ctxInfo.hasExtension("GL_EXT_raster_multisample")) {
+        GR_GL_GetIntegerv(gli, GR_GL_MAX_RASTER_SAMPLES, &fMaxRasterSamples);
+        // This is to guard against platforms that may not support as many samples for
+        // glRasterSamples as they do for framebuffers.
+        fMaxStencilSampleCount = SkTMin(fMaxStencilSampleCount, fMaxRasterSamples);
+    }
+    fMaxColorSampleCount = fMaxStencilSampleCount;
 
     if (kPowerVR54x_GrGLRenderer == ctxInfo.renderer() ||
         kPowerVRRogue_GrGLRenderer == ctxInfo.renderer() ||
         kAdreno3xx_GrGLRenderer == ctxInfo.renderer()) {
         fUseDrawInsteadOfClear = true;
     }
 
     if (kAdreno4xx_GrGLRenderer == ctxInfo.renderer()) {
         fUseDrawInsteadOfPartialRenderTargetWrite = true;
     }
@@ skipping 1194 matching lines @@
         for (int j = 0; j < kExternalFormatUsageCnt; ++j) {
             SkASSERT(defaultEntry.fFormats.fExternalFormat[j] !=
                      fConfigTable[i].fFormats.fExternalFormat[j]);
         }
         SkASSERT(defaultEntry.fFormats.fExternalType != fConfigTable[i].fFormats.fExternalType);
     }
 #endif
 }
 
 void GrGLCaps::onApplyOptionsOverrides(const GrContextOptions& options) {}