Draft change to start pulling uniform color into GP

src/gpu/GrGeometryProcessor.h

Index: src/gpu/GrGeometryProcessor.h
diff --git a/src/gpu/GrGeometryProcessor.h b/src/gpu/GrGeometryProcessor.h
index 50ecac48ba0c74a33d27dbf29bd1f203ab9f3051..d192f8fa5b23573c4d186c072e9727180fa74fae 100644
--- a/src/gpu/GrGeometryProcessor.h
+++ b/src/gpu/GrGeometryProcessor.h
@@ -21,18 +21,18 @@ class GrBatchTracker {
 public:
     template <typename T> const T& cast() const {
         SkASSERT(sizeof(T) <= kMaxSize);
-        return *reinterpret_cast<const T*>(fData);
+        return *reinterpret_cast<const T*>(fData.get());
     }
 
     template <typename T> T* cast() {
         SkASSERT(sizeof(T) <= kMaxSize);
-        return reinterpret_cast<T*>(fData);
+        return reinterpret_cast<T*>(fData.get());
     }
 
     static const size_t kMaxSize = 32;
 
 private:
-    uint8_t fData[kMaxSize];
+    mutable SkAlignedSStorage<kMaxSize> fData;
 };
 
 class GrGLCaps;
@@ -56,6 +56,12 @@ private:
     typedef GrProcessor INHERITED;
 };
 
+enum GPInput {

[bsalomon, 2014/12/12 14:29:35]

Can this be nested inside GrGP? Otherwise it needs a Gr prefix. Also needs some
dox.

+    kAllOnes_GPInput,
+    kAttribute_GPInput,
+    kUniform_GPInput,
+};
+
 /**
  * A GrGeometryProcessor is used to perform computation in the vertex shader and
  * add support for custom vertex attributes. A GrGemeotryProcessor is typically
@@ -151,15 +157,31 @@ public:
         return this->onIsEqual(that);
     }
 
+    /*
+     * This struct allows the optstate to communicate requirements to the GP.
+     * TODO when the GP can encapsulate draw information in bundles, we can refactor this struct.
+     * Ultimately, when setColor and setCoverage live on the GP, this struct can be replaced with
+     * a simple override color passed into initBatchTracker

[bsalomon, 2014/12/12 14:29:35]

From discussion with Greg, I think this will become

bool fColorOutputIgnored; // the GP doesn't write a color output
GrColor fColorOverride; // respect if !fColorOutputIgnored and not
Gr_ColorINVALID.

and similar for coverage, though maybe no need for override there...

+     */
     struct InitBT {
         bool fOutputColor;
         bool fOutputCoverage;
+        bool fRemoveColorAttr;
+        bool fRemoveCoverageAttr;
         GrColor fColor;
         GrColor fCoverage;
     };
 
-    virtual void initBatchTracker(GrBatchTracker*, const InitBT&) const {}
+    virtual void initBatchTracker(GrBatchTracker*, const InitBT&) const = 0;
 
+    // TODO this call is temporary.  Once we have deferred geometry, GPs can always make themselves
+    // equal
+    bool canBatch(const GrBatchTracker& left, const GrBatchTracker& right) const {
+        return this->onCanBatch(left, right);
+    }
+
+    virtual bool onCanBatch(const GrBatchTracker&, const GrBatchTracker&) const = 0;
+    
     GrColor color() const { return fColor; }
     uint8_t coverage() const { return fCoverage; }
 
@@ -173,6 +195,30 @@ public:
     void getInvariantOutputCoverage(GrInitInvariantOutput* out) const SK_OVERRIDE;
 
 protected:
+    static GPInput GetColorInputType(const InitBT& init, bool hasVertexColor) {

[bsalomon, 2014/12/12 14:29:35]

Document?

+        bool hasUniformColor = (init.fOutputColor && !hasVertexColor) || init.fRemoveColorAttr;
+        if (!init.fOutputColor) {
+            return kAllOnes_GPInput;
+        } else if (hasUniformColor) {
+            return kUniform_GPInput;
+        } else {
+            SkASSERT(hasVertexColor);
+            return kAttribute_GPInput;
+        }
+    }
+
+    static bool CanCombineOutput(GPInput left, GrColor lColor, GPInput right, GrColor rColor) {

[bsalomon, 2014/12/12 14:29:35]

Document?

+        if (left != right) {
+            return false;
+        }
+
+        if (kUniform_GPInput == left && lColor != rColor) {
+            return false;
+        }
+
+        return true;
+    }
+
     /**
      * Subclasses call this from their constructor to register vertex attributes.  Attributes
      * will be padded to the nearest 4 bytes for performance reasons.