Add GrEffect::updateKnownColorComponents(). It is used to determine whether the output of an effect has a constant output value for r,g,b, or a.

Review URL: https://codereview.appspot.com/7064057

git-svn-id: http://skia.googlecode.com/svn/trunk@7144 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 7 insertions, 0 deletions

diff --git a/src/effects/SkLightingImageFilter.cpp b/src/effects/SkLightingImageFilter.cpp
index 48f16b3ff8..fc819deb17 100644
--- a/src/effects/SkLightingImageFilter.cpp
+++ b/src/effects/SkLightingImageFilter.cpp
@@ -311,6 +311,13 @@ public:
 
     const SkLight* light() const { return fLight; }
     SkScalar surfaceScale() const { return fSurfaceScale; }
+
+    virtual void getConstantColorComponents(GrColor* color,
+                                            uint32_t* validFlags) const SK_OVERRIDE {
+        // lighting shaders are complicated. We just throw up our hands.
+        *validFlags = 0;
+    }
+
 private:
     typedef GrSingleTextureEffect INHERITED;
     const SkLight* fLight;