Enable stencil clipping in mixed sampled render targets

src/gpu/gl/GrGLRenderTarget.h

Index: src/gpu/gl/GrGLRenderTarget.h
diff --git a/src/gpu/gl/GrGLRenderTarget.h b/src/gpu/gl/GrGLRenderTarget.h
index d1365efd420c10af802bd173fd534a4d443871cd..4987c4c53096fe91de9efa022919c71abcb678a6 100644
--- a/src/gpu/gl/GrGLRenderTarget.h
+++ b/src/gpu/gl/GrGLRenderTarget.h
@@ -70,6 +70,46 @@ public:
     // components seperately.
     void dumpMemoryStatistics(SkTraceMemoryDump* traceMemoryDump) const override;
 
+    /**
+     * Some hardware allows overriding coordinates of sample locations in multisampled
+     * render targets.
+     */
+    enum SampleLocationsConfig {
+        kDefault_SampleLocationsConfig = 0,
+        kProgrammable_SampleLocationsConfig = 1
+    };

[Chris Dalton, 2015/09/22 08:35:25]

Just a thought -- we may want to consider putting the sample locations stuff in
GrRenderTargetPriv instead. What do you think?

+
+    /** Returns sample locations config in use. */
+    SampleLocationsConfig sampleLocationsConfig() { return fSampleLocationsConfig; }
+
+    /** Set sample locations config in use. */
+    void setSampleLocationsConfig(SampleLocationsConfig sampleLocationsConfig) {
+        fSampleLocationsConfig = sampleLocationsConfig;
+    }
+
+    /** Returns a pointer to default sample locations array. */
+    const float* defaultSampleLocations() { return fDefaultSampleLocations; }
+
+    /** Initializes default sample locations array with 'count' pairs of sample location coordinates.  */
+    void setDefaultSampleLocations(int count, const float *sampleLocations) {
+        memcpy(fDefaultSampleLocations, sampleLocations, 2 * count * sizeof(fDefaultSampleLocations[0]));
+    }
+
+    /**
+     * @return true if programmable sample locations have been set for this
+     *         render target.  Requires support for NV_sample_locations.
+     */
+    bool usesProgrammableSampleLocations() const {
+        return fUsesProgrammableSampleLocations;
+    }
+
+    /**
+     * Flag render target as using or not using programmable sample locations.
+     */
+    void flagAsUsingProgrammableSampleLocations(bool useSampleLocations) {
+        fUsesProgrammableSampleLocations = useSampleLocations;
+    }
+
 protected:
     // The public constructor registers this object with the cache. However, only the most derived
     // class should register with the cache. This constructor does not do the registration and
@@ -99,22 +139,29 @@ private:
     // The number total number of samples, including both MSAA and resolve texture samples.
     int totalSamples() const;
 
-    GrGLuint    fRTFBOID;
-    GrGLuint    fTexFBOID;
-    GrGLuint    fMSColorRenderbufferID;
+    GrGLuint              fRTFBOID;
+    GrGLuint              fTexFBOID;
+    GrGLuint              fMSColorRenderbufferID;
 
     // We track this separately from GrGpuResource because this may be both a texture and a render
     // target, and the texture may be wrapped while the render target is not.
-    LifeCycle   fRTLifecycle;
+    LifeCycle             fRTLifecycle;
 
     // when we switch to this render target we want to set the viewport to
     // only render to content area (as opposed to the whole allocation) and
     // we want the rendering to be at top left (GL has origin in bottom left)
-    GrGLIRect   fViewport;
+    GrGLIRect             fViewport;
 
     // onGpuMemorySize() needs to know the VRAM footprint of the FBO(s). However, abandon and
     // release zero out the IDs and the cache needs to know the size even after those actions.
-    size_t      fGpuMemorySize;
+    size_t                fGpuMemorySize;
+
+    // Configures sample locations to be either default or programmable, if MSAA.
+    SampleLocationsConfig fSampleLocationsConfig;
+    // Render target's default sample locations array, if MSAA.
+    float                 fDefaultSampleLocations[32];
+
+    bool                  fUsesProgrammableSampleLocations;
 
     typedef GrRenderTarget INHERITED;
 };