| /* |
| * Copyright 2014 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "GrConvexPolyEffect.h" |
| |
| #include "gl/GrGLEffect.h" |
| #include "gl/GrGLSL.h" |
| #include "gl/GrGLVertexEffect.h" |
| #include "GrTBackendEffectFactory.h" |
| |
| #include "SkPath.h" |
| |
| class GrGLConvexPolyEffect : public GrGLEffect { |
| public: |
| GrGLConvexPolyEffect(const GrBackendEffectFactory&, const GrDrawEffect&); |
| |
| virtual void emitCode(GrGLShaderBuilder* builder, |
| const GrDrawEffect& drawEffect, |
| EffectKey key, |
| const char* outputColor, |
| const char* inputColor, |
| const TransformedCoordsArray&, |
| const TextureSamplerArray&) SK_OVERRIDE; |
| |
| static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&); |
| |
| virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE; |
| |
| private: |
| GrGLUniformManager::UniformHandle fEdgeUniform; |
| SkScalar fPrevEdges[3 * GrConvexPolyEffect::kMaxEdges]; |
| typedef GrGLEffect INHERITED; |
| }; |
| |
| GrGLConvexPolyEffect::GrGLConvexPolyEffect(const GrBackendEffectFactory& factory, |
| const GrDrawEffect& drawEffect) |
| : INHERITED (factory) { |
| fPrevEdges[0] = SK_ScalarNaN; |
| } |
| |
| void GrGLConvexPolyEffect::emitCode(GrGLShaderBuilder* builder, |
| const GrDrawEffect& drawEffect, |
| EffectKey key, |
| const char* outputColor, |
| const char* inputColor, |
| const TransformedCoordsArray&, |
| const TextureSamplerArray& samplers) { |
| const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>(); |
| |
| const char *edgeArrayName; |
| fEdgeUniform = builder->addUniformArray(GrGLShaderBuilder::kFragment_Visibility, |
| kVec3f_GrSLType, |
| "edges", |
| cpe.getEdgeCount(), |
| &edgeArrayName); |
| builder->fsCodeAppend("\t\tfloat alpha = 1.0;\n"); |
| builder->fsCodeAppend("\t\tfloat edge;\n"); |
| const char* fragmentPos = builder->fragmentPosition(); |
| for (int i = 0; i < cpe.getEdgeCount(); ++i) { |
| builder->fsCodeAppendf("\t\tedge = dot(%s[%d], vec3(%s.x, %s.y, 1));\n", |
| edgeArrayName, i, fragmentPos, fragmentPos); |
| switch (cpe.getEdgeType()) { |
| case GrConvexPolyEffect::kFillAA_EdgeType: |
| builder->fsCodeAppend("\t\tedge = clamp(edge, 0.0, 1.0);\n"); |
| builder->fsCodeAppend("\t\talpha *= edge;\n"); |
| break; |
| case GrConvexPolyEffect::kFillNoAA_EdgeType: |
| builder->fsCodeAppend("\t\tedge = edge >= 0.5 ? 1.0 : 0.0;\n"); |
| builder->fsCodeAppend("\t\talpha *= edge;\n"); |
| break; |
| } |
| } |
| |
| builder->fsCodeAppendf("\t%s = %s;\n", outputColor, |
| (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str()); |
| } |
| |
| void GrGLConvexPolyEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) { |
| const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>(); |
| size_t byteSize = 3 * cpe.getEdgeCount() * sizeof(SkScalar); |
| if (0 != memcmp(fPrevEdges, cpe.getEdges(), byteSize)) { |
| uman.set3fv(fEdgeUniform, cpe.getEdgeCount(), cpe.getEdges()); |
| memcpy(fPrevEdges, cpe.getEdges(), byteSize); |
| } |
| } |
| |
| GrGLEffect::EffectKey GrGLConvexPolyEffect::GenKey(const GrDrawEffect& drawEffect, |
| const GrGLCaps&) { |
| const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>(); |
| GR_STATIC_ASSERT(GrConvexPolyEffect::kEdgeTypeCnt <= 4); |
| return (cpe.getEdgeCount() << 2) | cpe.getEdgeType(); |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| GrEffectRef* GrConvexPolyEffect::Create(EdgeType type, const SkPath& path) { |
| if (path.getSegmentMasks() != SkPath::kLine_SegmentMask || |
| !path.isConvex() || |
| path.isInverseFillType()) { |
| return NULL; |
| } |
| |
| if (path.countPoints() > kMaxEdges) { |
| return NULL; |
| } |
| |
| SkPoint pts[kMaxEdges]; |
| SkScalar edges[3 * kMaxEdges]; |
| |
| SkPath::Direction dir; |
| SkAssertResult(path.cheapComputeDirection(&dir)); |
| |
| int count = path.getPoints(pts, kMaxEdges); |
| int n = 0; |
| for (int lastPt = count - 1, i = 0; i < count; lastPt = i++) { |
| if (pts[lastPt] != pts[i]) { |
| SkVector v = pts[i] - pts[lastPt]; |
| v.normalize(); |
| if (SkPath::kCCW_Direction == dir) { |
| edges[3 * n] = v.fY; |
| edges[3 * n + 1] = -v.fX; |
| } else { |
| edges[3 * n] = -v.fY; |
| edges[3 * n + 1] = v.fX; |
| } |
| edges[3 * n + 2] = -(edges[3 * n] * pts[i].fX + edges[3 * n + 1] * pts[i].fY); |
| ++n; |
| } |
| } |
| return Create(type, n, edges); |
| } |
| |
| GrConvexPolyEffect::~GrConvexPolyEffect() {} |
| |
| void GrConvexPolyEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const { |
| *validFlags = 0; |
| } |
| |
| const GrBackendEffectFactory& GrConvexPolyEffect::getFactory() const { |
| return GrTBackendEffectFactory<GrConvexPolyEffect>::getInstance(); |
| } |
| |
| GrConvexPolyEffect::GrConvexPolyEffect(EdgeType edgeType, int n, const SkScalar edges[]) |
| : fEdgeType(edgeType) |
| , fEdgeCount(n) { |
| // Factory function should have already ensured this. |
| SkASSERT(n <= kMaxEdges); |
| memcpy(fEdges, edges, 3 * n * sizeof(SkScalar)); |
| // Outset the edges by 0.5 so that a pixel with center on an edge is 50% covered in the AA case |
| // and 100% covered in the non-AA case. |
| for (int i = 0; i < n; ++i) { |
| fEdges[3 * i + 2] += SK_ScalarHalf; |
| } |
| this->setWillReadFragmentPosition(); |
| } |
| |
| bool GrConvexPolyEffect::onIsEqual(const GrEffect& other) const { |
| const GrConvexPolyEffect& cpe = CastEffect<GrConvexPolyEffect>(other); |
| // ignore the fact that 0 == -0 and just use memcmp. |
| return (cpe.fEdgeType == fEdgeType && cpe.fEdgeCount == fEdgeCount && |
| 0 == memcmp(cpe.fEdges, fEdges, 3 * fEdgeCount * sizeof(SkScalar))); |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| GR_DEFINE_EFFECT_TEST(GrConvexPolyEffect); |
| |
| GrEffectRef* GrConvexPolyEffect::TestCreate(SkRandom* random, |
| GrContext*, |
| const GrDrawTargetCaps& caps, |
| GrTexture*[]) { |
| EdgeType edgeType = static_cast<EdgeType>(random->nextULessThan(kEdgeTypeCnt)); |
| int count = random->nextULessThan(kMaxEdges + 1); |
| SkScalar edges[kMaxEdges * 3]; |
| for (int i = 0; i < 3 * count; ++i) { |
| edges[i] = random->nextSScalar1(); |
| } |
| |
| return GrConvexPolyEffect::Create(edgeType, count, edges); |
| } |
| |