| /* |
| * Copyright 2014 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef GrConvexPolyEffect_DEFINED |
| #define GrConvexPolyEffect_DEFINED |
| |
| #include "GrDrawTargetCaps.h" |
| #include "GrEffect.h" |
| #include "GrVertexEffect.h" |
| |
| class GrGLConvexPolyEffect; |
| class SkPath; |
| |
| /** |
| * An effect that renders a convex polygon. It is intended to be used as a coverage effect. |
| * Bounding geometry is rendered and the effect computes coverage based on the fragment's |
| * position relative to the polygon. |
| */ |
| class GrConvexPolyEffect : public GrEffect { |
| public: |
| /** This could be expanded to include a AA hairline mode. If so, unify with GrBezierEffect's |
| enum. */ |
| enum EdgeType { |
| kFillNoAA_EdgeType, |
| kFillAA_EdgeType, |
| |
| kLastEdgeType = kFillAA_EdgeType, |
| }; |
| |
| enum { |
| kEdgeTypeCnt = kLastEdgeType + 1, |
| kMaxEdges = 8, |
| }; |
| |
| /** |
| * edges is a set of n edge equations where n is limited to kMaxEdges. It contains 3*n values. |
| * The edges should form a convex polygon. The positive half-plane is considered to be the |
| * inside. The equations should be normalized such that the first two coefficients are a unit |
| * 2d vector. |
| * |
| * Currently the edges are specified in device space. In the future we may prefer to specify |
| * them in src space. There are a number of ways this could be accomplished but we'd probably |
| * have to modify the effect/shaderbuilder interface to make it possible (e.g. give access |
| * to the view matrix or untransformed positions in the fragment shader). |
| */ |
| static GrEffectRef* Create(EdgeType edgeType, int n, const SkScalar edges[]) { |
| if (n <= 0 || n > kMaxEdges) { |
| return NULL; |
| } |
| return CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrConvexPolyEffect, |
| (edgeType, n, edges)))); |
| } |
| |
| /** |
| * Creates an effect that clips against the path. If the path is not a convex polygon, is |
| * inverse filled, or has too many edges, this will return NULL. |
| */ |
| static GrEffectRef* Create(EdgeType, const SkPath&); |
| |
| virtual ~GrConvexPolyEffect(); |
| |
| static const char* Name() { return "ConvexPoly"; } |
| |
| EdgeType getEdgeType() const { return fEdgeType; } |
| |
| int getEdgeCount() const { return fEdgeCount; } |
| |
| const SkScalar* getEdges() const { return fEdges; } |
| |
| typedef GrGLConvexPolyEffect GLEffect; |
| |
| virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE; |
| |
| virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE; |
| |
| private: |
| GrConvexPolyEffect(EdgeType edgeType, int n, const SkScalar edges[]); |
| |
| virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE; |
| |
| EdgeType fEdgeType; |
| int fEdgeCount; |
| SkScalar fEdges[3 * kMaxEdges]; |
| |
| GR_DECLARE_EFFECT_TEST; |
| |
| typedef GrEffect INHERITED; |
| }; |
| |
| |
| #endif |