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
diff --git a/include/gpu/GrEffect.h b/include/gpu/GrEffect.h
index b12a346..5fca4b2 100644
--- a/include/gpu/GrEffect.h
+++ b/include/gpu/GrEffect.h
@@ -8,9 +8,10 @@
#ifndef GrEffect_DEFINED
#define GrEffect_DEFINED
-#include "GrRefCnt.h"
-#include "GrNoncopyable.h"
+#include "GrColor.h"
#include "GrEffectUnitTest.h"
+#include "GrNoncopyable.h"
+#include "GrRefCnt.h"
#include "GrTexture.h"
#include "GrTextureAccess.h"
@@ -31,9 +32,27 @@
GrEffect() {};
virtual ~GrEffect();
- /** If given an input texture that is/is not opaque, is this effect guaranteed to produce an
- opaque output? */
- virtual bool isOpaque(bool inputTextureIsOpaque) const;
+ /**
+ * Flags for getConstantColorComponents. They are defined so that the bit order reflects the
+ * GrColor shift order.
+ */
+ enum ValidComponentFlags {
+ kR_ValidComponentFlag = 1 << (GrColor_SHIFT_R / 8),
+ kG_ValidComponentFlag = 1 << (GrColor_SHIFT_G / 8),
+ kB_ValidComponentFlag = 1 << (GrColor_SHIFT_B / 8),
+ kA_ValidComponentFlag = 1 << (GrColor_SHIFT_A / 8),
+
+ kAll_ValidComponentFlags = (kR_ValidComponentFlag | kG_ValidComponentFlag |
+ kB_ValidComponentFlag | kA_ValidComponentFlag)
+ };
+
+ /**
+ * This function is used to perform optimizations. When called the color and validFlags params
+ * indicate whether the input components to this effect in the FS will have known values. The
+ * function updates both params to indicate known values of its output. A component of the color
+ * param only has meaning if the corresponding bit in validFlags is set.
+ */
+ virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const = 0;
/** This object, besides creating back-end-specific helper objects, is used for run-time-type-
identification. The factory should be an instance of templated class,