Add XferProcessor factory in GrPaint and GrDrawState.

src/core/SkXfermode.cpp

Index: src/core/SkXfermode.cpp
diff --git a/src/core/SkXfermode.cpp b/src/core/SkXfermode.cpp
index 4a3ec397022e34a6201feeafde73032a7915332a..adbb955c92e1747e405714b5b6f2117418c9f394 100644
--- a/src/core/SkXfermode.cpp
+++ b/src/core/SkXfermode.cpp
@@ -6,7 +6,6 @@
  * found in the LICENSE file.
  */
 
-
 #include "SkXfermode.h"
 #include "SkXfermode_opts_SSE2.h"
 #include "SkXfermode_proccoeff.h"
@@ -680,16 +679,42 @@ bool SkXfermode::asFragmentProcessor(GrFragmentProcessor**, GrTexture*) const {
     return false;
 }
 
-bool SkXfermode::asFragmentProcessorOrCoeff(SkXfermode* xfermode, GrFragmentProcessor** fp,
-                                            Coeff* src, Coeff* dst, GrTexture* background) {
+bool SkXfermode::asXPFactory(GrXPFactory**) const {
+    return false;
+}
+
+
+#if SK_SUPPORT_GPU
+#include "effects/GrPorterDuffXferProcessor.h"
+
+bool SkXfermode::AsFragmentProcessorOrXPFactory(SkXfermode* xfermode,
+                                                GrFragmentProcessor** fp,
+                                                GrXPFactory** xpf,
+                                                Coeff* src, Coeff* dst) {
     if (NULL == xfermode) {
-        return ModeAsCoeff(kSrcOver_Mode, src, dst);
+        SkAssertResult(ModeAsCoeff(kSrcOver_Mode, src, dst));
+        *xpf = GrPorterDuffXPFactory::Create(*src, *dst);
+        return true;
     } else if (xfermode->asCoeff(src, dst)) {
+        *xpf = GrPorterDuffXPFactory::Create(*src, *dst);
+        return true;
+    } else if (xfermode->asXPFactory(xpf)) {
+        *src = SkXfermode::kOne_Coeff;
+        *src = SkXfermode::kZero_Coeff;

[bsalomon, 2014/12/02 15:36:32]

Should this be dst?

Is it possible to stop having src/dst coeff params to this function? It seems
like the coeffs are always either baked into the XPF or in the case of an FP
result can be assumed to be one/zero.

[egdaniel, 2014/12/02 18:09:51]

Yeah should be dst. All these src and dst things go away in the next CL where
are blending is encapsulated inside the XP. In this CL blending is still handled
outside the XP.

         return true;
     } else {
-        return xfermode->asFragmentProcessor(fp, background);
+        return xfermode->asFragmentProcessor(fp);
     }
 }
+#else
+bool SkXfermode::AsFragmentProcessorOrXPFactory(SkXfermode* xfermode,
+                                                GrFragmentProcessor** fp,
+                                                GrXPFactory** xpf,
+                                                Coeff* src, Coeff* dst,
+                                                GrTexture* background) {
+    return false;
+}
+#endif
 
 SkPMColor SkXfermode::xferColor(SkPMColor src, SkPMColor dst) const{
     // no-op. subclasses should override this