Implement support for mixed sampled render targets

include/gpu/GrRenderTarget.h

Index: include/gpu/GrRenderTarget.h
diff --git a/include/gpu/GrRenderTarget.h b/include/gpu/GrRenderTarget.h
index 40e006aa8aec8edb70b28cec5a3274f5b7f0e110..d77d29ba87e4a1f595b6783c96aa15279217023d 100644
--- a/include/gpu/GrRenderTarget.h
+++ b/include/gpu/GrRenderTarget.h
@@ -31,14 +31,32 @@ public:
 
     // GrRenderTarget
     /**
-     * @return true if the surface is multisampled, false otherwise
+     * @param requestedConfig

[Chris Dalton, 2015/03/14 02:51:30]

Oops, sorry. I didn't finish my previous comment and then forgot to get back to
it. We should also document the requestedConfig parameter in the comment, not
just list it. But since we may reconsider these enum names it can probably wait.

+     * @return true if the surface is multisampled in all of the buffers
+     *         specified by the sample config, false if any are non-MSAA
      */
-    bool isMultisampled() const { return 0 != fDesc.fSampleCnt; }
+    bool isMultisampled(GrSampleConfig requestedConfig = kUnified_GrSampleConfig) const {
+        return 0 != numSamples(requestedConfig);
+    }
 
     /**
-     * @return the number of samples-per-pixel or zero if non-MSAA.
+     * @return the number of samples-per-pixel or zero if any of the specified
+     *         buffers is non-MSAA.
      */
-    int numSamples() const { return fDesc.fSampleCnt; }
+    int numSamples(GrSampleConfig requestedConfig = kUnified_GrSampleConfig) const {
+        if (kStencil_GrSampleConfig == fSampleConfig &&
+            kUnified_GrSampleConfig == requestedConfig) {
+            return 0;
+        }
+        return fDesc.fSampleCnt;
+    }
+
+    /**
+     * @return sample config.
+     */
+    GrSampleConfig sampleConfig() {
+        return fSampleConfig;
+    }
 
     /**
      * Call to indicate the multisample contents were modified such that the
@@ -94,8 +112,10 @@ public:
     const GrRenderTargetPriv renderTargetPriv() const;
 
 protected:
-    GrRenderTarget(GrGpu* gpu, LifeCycle lifeCycle, const GrSurfaceDesc& desc)
+    GrRenderTarget(GrGpu* gpu, LifeCycle lifeCycle, const GrSurfaceDesc& desc,
+                   GrSampleConfig sampleConfig)
         : INHERITED(gpu, lifeCycle, desc)
+        , fSampleConfig(sampleConfig)
         , fStencilBuffer(NULL) {
         fResolveRect.setLargestInverted();
     }
@@ -110,6 +130,8 @@ private:
 
     friend class GrRenderTargetPriv;
 
+    GrSampleConfig    fSampleConfig;
+
     GrStencilBuffer*  fStencilBuffer;
 
     SkIRect           fResolveRect;