1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/gpu/effects/GrConvexPolyEffect.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,91 @@
1.4 +/*
1.5 + * Copyright 2014 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef GrConvexPolyEffect_DEFINED
1.12 +#define GrConvexPolyEffect_DEFINED
1.13 +
1.14 +#include "GrDrawTargetCaps.h"
1.15 +#include "GrEffect.h"
1.16 +#include "GrTypesPriv.h"
1.17 +
1.18 +class GrGLConvexPolyEffect;
1.19 +class SkPath;
1.20 +
1.21 +/**
1.22 + * An effect that renders a convex polygon. It is intended to be used as a coverage effect.
1.23 + * Bounding geometry is rendered and the effect computes coverage based on the fragment's
1.24 + * position relative to the polygon.
1.25 + */
1.26 +class GrConvexPolyEffect : public GrEffect {
1.27 +public:
1.28 + enum {
1.29 + kMaxEdges = 8,
1.30 + };
1.31 +
1.32 + /**
1.33 + * edges is a set of n edge equations where n is limited to kMaxEdges. It contains 3*n values.
1.34 + * The edges should form a convex polygon. The positive half-plane is considered to be the
1.35 + * inside. The equations should be normalized such that the first two coefficients are a unit
1.36 + * 2d vector.
1.37 + *
1.38 + * Currently the edges are specified in device space. In the future we may prefer to specify
1.39 + * them in src space. There are a number of ways this could be accomplished but we'd probably
1.40 + * have to modify the effect/shaderbuilder interface to make it possible (e.g. give access
1.41 + * to the view matrix or untransformed positions in the fragment shader).
1.42 + */
1.43 + static GrEffectRef* Create(GrEffectEdgeType edgeType, int n, const SkScalar edges[]) {
1.44 + if (n <= 0 || n > kMaxEdges || kHairlineAA_GrEffectEdgeType == edgeType) {
1.45 + return NULL;
1.46 + }
1.47 + return CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrConvexPolyEffect,
1.48 + (edgeType, n, edges))));
1.49 + }
1.50 +
1.51 + /**
1.52 + * Creates an effect that clips against the path. If the path is not a convex polygon, is
1.53 + * inverse filled, or has too many edges, this will return NULL. If offset is non-NULL, then
1.54 + * the path is translated by the vector.
1.55 + */
1.56 + static GrEffectRef* Create(GrEffectEdgeType, const SkPath&, const SkVector* offset = NULL);
1.57 +
1.58 + /**
1.59 + * Creates an effect that fills inside the rect with AA edges..
1.60 + */
1.61 + static GrEffectRef* Create(GrEffectEdgeType, const SkRect&);
1.62 +
1.63 + virtual ~GrConvexPolyEffect();
1.64 +
1.65 + static const char* Name() { return "ConvexPoly"; }
1.66 +
1.67 + GrEffectEdgeType getEdgeType() const { return fEdgeType; }
1.68 +
1.69 + int getEdgeCount() const { return fEdgeCount; }
1.70 +
1.71 + const SkScalar* getEdges() const { return fEdges; }
1.72 +
1.73 + typedef GrGLConvexPolyEffect GLEffect;
1.74 +
1.75 + virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const SK_OVERRIDE;
1.76 +
1.77 + virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
1.78 +
1.79 +private:
1.80 + GrConvexPolyEffect(GrEffectEdgeType edgeType, int n, const SkScalar edges[]);
1.81 +
1.82 + virtual bool onIsEqual(const GrEffect& other) const SK_OVERRIDE;
1.83 +
1.84 + GrEffectEdgeType fEdgeType;
1.85 + int fEdgeCount;
1.86 + SkScalar fEdges[3 * kMaxEdges];
1.87 +
1.88 + GR_DECLARE_EFFECT_TEST;
1.89 +
1.90 + typedef GrEffect INHERITED;
1.91 +};
1.92 +
1.93 +
1.94 +#endif
