Replace edge types with GrEdgeEffect.

This strips out last of the edge types and the fixed function edge attribute and replaces them with using GrEdgeEffect. Also fixes a minor bug when checking attribute counts -- it was using kAttribIndexCount instead of kVertexAttribCnt. 

Original Author: jvanverth@google.com
Review URL: https://codereview.chromium.org/13069003

git-svn-id: http://skia.googlecode.com/svn/trunk@8392 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 85 insertions, 0 deletions

diff --git a/src/gpu/effects/GrEdgeEffect.h b/src/gpu/effects/GrEdgeEffect.h
new file mode 100644
index 0000000000..c6238a2e09
--- /dev/null
+++ b/src/gpu/effects/GrEdgeEffect.h
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrEdgeEffect_DEFINED
+#define GrEdgeEffect_DEFINED
+
+#include "GrEffect.h"
+
+class GrGLEdgeEffect;
+
+/**
+ * The output of this effect is one of three different edge types: hairlines, quads, 
+ * and hairline quads.
+ */
+
+class GrEdgeEffect : public GrEffect {
+public:
+    enum EdgeType {
+        /* 1-pixel wide line
+           2D implicit device coord line eq (a*x + b*y +c = 0). 4th component unused. */
+        kHairLine_EdgeType = 0,
+        /* Quadratic specified by 0=u^2-v canonical coords. u and v are the first
+           two components of the vertex attribute. Coverage is based on signed
+           distance with negative being inside, positive outside. The edge is specified in
+           window space (y-down). If either the third or fourth component of the interpolated
+           vertex coord is > 0 then the pixel is considered outside the edge. This is used to
+           attempt to trim to a portion of the infinite quad. Requires shader derivative
+           instruction support. */
+        kQuad_EdgeType,
+        /* Similar to above but for hairline quadratics. Uses unsigned distance.
+           Coverage is min(0, 1-distance). 3rd & 4th component unused. Requires
+           shader derivative instruction support. */
+        kHairQuad_EdgeType,
+
+        kLast_EdgeType = kHairQuad_EdgeType
+    };
+    static const int kEdgeTypeCount = kLast_EdgeType + 1;
+
+    static GrEffectRef* Create(EdgeType type) {
+        // we go through this so we only have one copy of each effect
+        static GrEffectRef* gEdgeEffectRef[kEdgeTypeCount] = {
+            CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrEdgeEffect, (kHairLine_EdgeType)))),
+            CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrEdgeEffect, (kQuad_EdgeType)))),
+            CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrEdgeEffect, (kHairQuad_EdgeType)))),
+        };
+        static SkAutoTUnref<GrEffectRef> gUnref0(gEdgeEffectRef[0]);
+        static SkAutoTUnref<GrEffectRef> gUnref1(gEdgeEffectRef[1]);
+        static SkAutoTUnref<GrEffectRef> gUnref2(gEdgeEffectRef[2]);
+        
+        gEdgeEffectRef[type]->ref();
+        return gEdgeEffectRef[type];
+    }
+
+    virtual ~GrEdgeEffect() {}
+
+    static const char* Name() { return "Edge"; }
+
+    virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
+
+    typedef GrGLEdgeEffect GLEffect;
+
+    virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
+
+    EdgeType edgeType() const { return fEdgeType; }
+
+private:
+    GrEdgeEffect(EdgeType edgeType);
+
+    virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE {
+        const GrEdgeEffect& qee = CastEffect<GrEdgeEffect>(other);
+        return qee.fEdgeType == fEdgeType;
+    }
+
+    EdgeType fEdgeType;
+
+    GR_DECLARE_EFFECT_TEST;
+
+    typedef GrEffect INHERITED;
+};
+
+#endif