Revert of removing equality / compute invariant loops from GrGeometryProcessors (patchset #2 id:20001 of https://codereview.chromium.org/1111603004/)

Reason for revert:
breaks gl programs

Original issue's description:
> removing equality / compute invariant loops from GrGeometryProcessors
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/ef292a0901205b9785a30daae2c036aa34a970ca

TBR=bsalomon@google.com,joshualitt@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1110993002

1 files changed, 52 insertions, 11 deletions

diff --git a/src/gpu/GrGeometryProcessor.h b/src/gpu/GrGeometryProcessor.h
index c380f20b0e..f0e0b0c008 100644
--- a/src/gpu/GrGeometryProcessor.h
+++ b/src/gpu/GrGeometryProcessor.h
@@ -23,33 +23,61 @@ public:
     // atleast bundles
     GrGeometryProcessor(GrColor color,
                         const SkMatrix& viewMatrix = SkMatrix::I(),
-                        const SkMatrix& localMatrix = SkMatrix::I())
+                        const SkMatrix& localMatrix = SkMatrix::I(),
+                        bool opaqueVertexColors = false)
         : INHERITED(viewMatrix, localMatrix, false)
         , fColor(color)
+        , fOpaqueVertexColors(opaqueVertexColors)
         , fWillUseGeoShader(false)
+        , fHasVertexColor(false)
         , fHasLocalCoords(false) {}
 
     bool willUseGeoShader() const { return fWillUseGeoShader; }
 
-    // TODO delete this when paths are in batch
+    /*
+     * In an ideal world, two GrGeometryProcessors with the same class id and texture accesses
+     * would ALWAYS be able to batch together.  If two GrGeometryProcesosrs are the same then we
+     * will only keep one of them.  The remaining GrGeometryProcessor then updates its
+     * GrBatchTracker to incorporate the draw information from the GrGeometryProcessor we discard.
+     * Any bundles associated with the discarded GrGeometryProcessor will be attached to the
+     * remaining GrGeometryProcessor.
+     */
     bool canMakeEqual(const GrBatchTracker& mine,
                       const GrPrimitiveProcessor& that,
                       const GrBatchTracker& theirs) const override {
-        SkFAIL("Unsupported\n");
-        return false;
+        if (this->classID() != that.classID() || !this->hasSameTextureAccesses(that)) {
+            return false;
+        }
+
+        // TODO let the GPs decide this
+        if (!this->viewMatrix().cheapEqualTo(that.viewMatrix())) {
+            return false;
+        }
+
+        // TODO remove the hint
+        const GrGeometryProcessor& other = that.cast<GrGeometryProcessor>();
+        if (fHasVertexColor && fOpaqueVertexColors != other.fOpaqueVertexColors) {
+            return false;
+        }
+
+        // TODO this equality test should really be broken up, some of this can live on the batch
+        // tracker test and some of this should be in bundles
+        if (!this->onIsEqual(other)) {
+            return false;
+        }
+
+        return this->onCanMakeEqual(mine, other, theirs);
     }
     
     // TODO we can remove color from the GrGeometryProcessor base class once we have bundles of
     // primitive data
     GrColor color() const { return fColor; }
 
-    // TODO Delete when paths are in batch
-    void getInvariantOutputColor(GrInitInvariantOutput* out) const override {
-        SkFAIL("Unsupported\n");
-    }
-    void getInvariantOutputCoverage(GrInitInvariantOutput* out) const override {
-        SkFAIL("Unsupported\n");
-    }
+    // TODO this is a total hack until the gp can do deferred geometry
+    bool hasVertexColor() const { return fHasVertexColor; }
+
+    void getInvariantOutputColor(GrInitInvariantOutput* out) const override;
+    void getInvariantOutputCoverage(GrInitInvariantOutput* out) const override;
 
 protected:
     /*
@@ -100,13 +128,26 @@ protected:
     void setWillUseGeoShader() { fWillUseGeoShader = true; }
 
     // TODO hack see above
+    void setHasVertexColor() { fHasVertexColor = true; }
     void setHasLocalCoords() { fHasLocalCoords = true; }
 
+    virtual void onGetInvariantOutputColor(GrInitInvariantOutput*) const {}
+    virtual void onGetInvariantOutputCoverage(GrInitInvariantOutput*) const = 0;
+
 private:
+    virtual bool onCanMakeEqual(const GrBatchTracker& mine,
+                                const GrGeometryProcessor& that,
+                                const GrBatchTracker& theirs) const = 0;
+
+    // TODO delete this when we have more advanced equality testing via bundles and the BT
+    virtual bool onIsEqual(const GrGeometryProcessor&) const = 0;
+
     bool hasExplicitLocalCoords() const override { return fHasLocalCoords; }
 
     GrColor fColor;
+    bool fOpaqueVertexColors;
     bool fWillUseGeoShader;
+    bool fHasVertexColor;
     bool fHasLocalCoords;
 
     typedef GrPrimitiveProcessor INHERITED;