Make GrSamplerState::operator==() use GrCustomStage::isEquivalent() rather

than just bit-compare all fields.



git-svn-id: http://skia.googlecode.com/svn/trunk@3805 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 23 insertions, 5 deletions

diff --git a/include/gpu/GrCustomStage.h b/include/gpu/GrCustomStage.h
index 82ad3ab9f8..4fe13bf34d 100644
--- a/include/gpu/GrCustomStage.h
+++ b/include/gpu/GrCustomStage.h
@@ -30,7 +30,13 @@ public:
     /** This pointer, besides creating back-end-specific helper
         objects, is used for run-time-type-identification. Every
         subclass must return a consistent unique value for it. */
-    virtual GrGLProgramStageFactory* getGLFactory() = 0;
+    virtual GrGLProgramStageFactory* getGLFactory() const = 0;
+
+    /** Returns true if the other custom stage will generate
+        a compatible/equivalent shader. Must only be called if
+        the two are already known to be of the same type (i.e.
+        they return the same value from getGLFactory()). */
+    virtual bool isEquivalent(const GrCustomStage *) const = 0;
 
 };
 
diff --git a/include/gpu/GrSamplerState.h b/include/gpu/GrSamplerState.h
index 50fe240c8d..3fd39c560a 100644
--- a/include/gpu/GrSamplerState.h
+++ b/include/gpu/GrSamplerState.h
@@ -111,10 +111,10 @@ public:
      * unfiltered, and use identity matrix.
      */
     GrSamplerState()
-    : fCustomStage (NULL)
-    , fRadial2CenterX1()
+    : fRadial2CenterX1()
     , fRadial2Radius0()
-    , fRadial2PosRoot() {
+    , fRadial2PosRoot()
+    , fCustomStage (NULL) {
         this->reset();
     }
 
@@ -123,7 +123,19 @@ public:
     }
 
     bool operator ==(const GrSamplerState& s) const {
-        return !memcmp(this, &s, sizeof(GrSamplerState));
+        /* We must be bit-identical as far as the CustomStage;
+           there may be multiple CustomStages that will produce
+           the same shader code and so are equivalent. 
+           Can't take the address of fWrapX because it's :8 */
+        int bitwiseRegion = (intptr_t) &fCustomStage - (intptr_t) this;
+        GrAssert(sizeof(GrSamplerState) ==
+                 bitwiseRegion + sizeof(fCustomStage));
+        return !memcmp(this, &s, bitwiseRegion) &&
+               ((fCustomStage == s.fCustomStage) ||
+                (fCustomStage && s.fCustomStage &&
+                 (fCustomStage->getGLFactory() ==
+                     s.fCustomStage->getGLFactory()) &&
+                 fCustomStage->isEquivalent(s.fCustomStage)));
     }
     bool operator !=(const GrSamplerState& s) const { return !(*this == s); }