commit-bot@chromium.org | c3fe549 | 2014-01-30 18:15:51 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2014 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #include "GrConvexPolyEffect.h" |
| 9 | |
| 10 | #include "gl/GrGLEffect.h" |
| 11 | #include "gl/GrGLSL.h" |
| 12 | #include "gl/GrGLVertexEffect.h" |
| 13 | #include "GrTBackendEffectFactory.h" |
| 14 | |
| 15 | #include "SkPath.h" |
| 16 | |
| 17 | class GrGLConvexPolyEffect : public GrGLEffect { |
| 18 | public: |
| 19 | GrGLConvexPolyEffect(const GrBackendEffectFactory&, const GrDrawEffect&); |
| 20 | |
| 21 | virtual void emitCode(GrGLShaderBuilder* builder, |
| 22 | const GrDrawEffect& drawEffect, |
| 23 | EffectKey key, |
| 24 | const char* outputColor, |
| 25 | const char* inputColor, |
| 26 | const TransformedCoordsArray&, |
| 27 | const TextureSamplerArray&) SK_OVERRIDE; |
| 28 | |
| 29 | static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&); |
| 30 | |
| 31 | virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) SK_OVERRIDE; |
| 32 | |
| 33 | private: |
| 34 | GrGLUniformManager::UniformHandle fEdgeUniform; |
| 35 | SkScalar fPrevEdges[3 * GrConvexPolyEffect::kMaxEdges]; |
| 36 | typedef GrGLEffect INHERITED; |
| 37 | }; |
| 38 | |
| 39 | GrGLConvexPolyEffect::GrGLConvexPolyEffect(const GrBackendEffectFactory& factory, |
| 40 | const GrDrawEffect& drawEffect) |
| 41 | : INHERITED (factory) { |
| 42 | fPrevEdges[0] = SK_ScalarNaN; |
| 43 | } |
| 44 | |
| 45 | void GrGLConvexPolyEffect::emitCode(GrGLShaderBuilder* builder, |
| 46 | const GrDrawEffect& drawEffect, |
| 47 | EffectKey key, |
| 48 | const char* outputColor, |
| 49 | const char* inputColor, |
| 50 | const TransformedCoordsArray&, |
| 51 | const TextureSamplerArray& samplers) { |
| 52 | const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>(); |
| 53 | |
| 54 | const char *edgeArrayName; |
| 55 | fEdgeUniform = builder->addUniformArray(GrGLShaderBuilder::kFragment_Visibility, |
| 56 | kVec3f_GrSLType, |
| 57 | "edges", |
| 58 | cpe.getEdgeCount(), |
| 59 | &edgeArrayName); |
| 60 | builder->fsCodeAppend("\t\tfloat alpha = 1.0;\n"); |
| 61 | builder->fsCodeAppend("\t\tfloat edge;\n"); |
| 62 | const char* fragmentPos = builder->fragmentPosition(); |
| 63 | for (int i = 0; i < cpe.getEdgeCount(); ++i) { |
| 64 | builder->fsCodeAppendf("\t\tedge = dot(%s[%d], vec3(%s.x, %s.y, 1));\n", |
| 65 | edgeArrayName, i, fragmentPos, fragmentPos); |
| 66 | switch (cpe.getEdgeType()) { |
| 67 | case GrConvexPolyEffect::kFillAA_EdgeType: |
| 68 | builder->fsCodeAppend("\t\tedge = clamp(edge, 0.0, 1.0);\n"); |
| 69 | builder->fsCodeAppend("\t\talpha *= edge;\n"); |
| 70 | break; |
| 71 | case GrConvexPolyEffect::kFillNoAA_EdgeType: |
| 72 | builder->fsCodeAppend("\t\tedge = edge >= 0.5 ? 1.0 : 0.0;\n"); |
| 73 | builder->fsCodeAppend("\t\talpha *= edge;\n"); |
| 74 | break; |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | builder->fsCodeAppendf("\t%s = %s;\n", outputColor, |
| 79 | (GrGLSLExpr4(inputColor) * GrGLSLExpr1("alpha")).c_str()); |
| 80 | } |
| 81 | |
| 82 | void GrGLConvexPolyEffect::setData(const GrGLUniformManager& uman, const GrDrawEffect& drawEffect) { |
| 83 | const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>(); |
| 84 | size_t byteSize = 3 * cpe.getEdgeCount() * sizeof(SkScalar); |
| 85 | if (0 != memcmp(fPrevEdges, cpe.getEdges(), byteSize)) { |
| 86 | uman.set3fv(fEdgeUniform, cpe.getEdgeCount(), cpe.getEdges()); |
| 87 | memcpy(fPrevEdges, cpe.getEdges(), byteSize); |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | GrGLEffect::EffectKey GrGLConvexPolyEffect::GenKey(const GrDrawEffect& drawEffect, |
| 92 | const GrGLCaps&) { |
| 93 | const GrConvexPolyEffect& cpe = drawEffect.castEffect<GrConvexPolyEffect>(); |
| 94 | GR_STATIC_ASSERT(GrConvexPolyEffect::kEdgeTypeCnt <= 4); |
| 95 | return (cpe.getEdgeCount() << 2) | cpe.getEdgeType(); |
| 96 | } |
| 97 | |
| 98 | ////////////////////////////////////////////////////////////////////////////// |
| 99 | |
| 100 | GrEffectRef* GrConvexPolyEffect::Create(EdgeType type, const SkPath& path) { |
| 101 | if (path.getSegmentMasks() != SkPath::kLine_SegmentMask || |
| 102 | !path.isConvex() || |
| 103 | path.isInverseFillType()) { |
| 104 | return NULL; |
| 105 | } |
| 106 | |
| 107 | if (path.countPoints() > kMaxEdges) { |
| 108 | return NULL; |
| 109 | } |
| 110 | |
| 111 | SkPoint pts[kMaxEdges]; |
| 112 | SkScalar edges[3 * kMaxEdges]; |
| 113 | |
| 114 | SkPath::Direction dir; |
| 115 | SkAssertResult(path.cheapComputeDirection(&dir)); |
| 116 | |
| 117 | int count = path.getPoints(pts, kMaxEdges); |
| 118 | int n = 0; |
| 119 | for (int lastPt = count - 1, i = 0; i < count; lastPt = i++) { |
| 120 | if (pts[lastPt] != pts[i]) { |
| 121 | SkVector v = pts[i] - pts[lastPt]; |
| 122 | v.normalize(); |
| 123 | if (SkPath::kCCW_Direction == dir) { |
| 124 | edges[3 * n] = v.fY; |
| 125 | edges[3 * n + 1] = -v.fX; |
| 126 | } else { |
| 127 | edges[3 * n] = -v.fY; |
| 128 | edges[3 * n + 1] = v.fX; |
| 129 | } |
| 130 | edges[3 * n + 2] = -(edges[3 * n] * pts[i].fX + edges[3 * n + 1] * pts[i].fY); |
| 131 | ++n; |
| 132 | } |
| 133 | } |
| 134 | return Create(type, n, edges); |
| 135 | } |
| 136 | |
| 137 | GrConvexPolyEffect::~GrConvexPolyEffect() {} |
| 138 | |
| 139 | void GrConvexPolyEffect::getConstantColorComponents(GrColor* color, uint32_t* validFlags) const { |
| 140 | *validFlags = 0; |
| 141 | } |
| 142 | |
| 143 | const GrBackendEffectFactory& GrConvexPolyEffect::getFactory() const { |
| 144 | return GrTBackendEffectFactory<GrConvexPolyEffect>::getInstance(); |
| 145 | } |
| 146 | |
| 147 | GrConvexPolyEffect::GrConvexPolyEffect(EdgeType edgeType, int n, const SkScalar edges[]) |
| 148 | : fEdgeType(edgeType) |
| 149 | , fEdgeCount(n) { |
| 150 | // Factory function should have already ensured this. |
| 151 | SkASSERT(n <= kMaxEdges); |
| 152 | memcpy(fEdges, edges, 3 * n * sizeof(SkScalar)); |
| 153 | // Outset the edges by 0.5 so that a pixel with center on an edge is 50% covered in the AA case |
| 154 | // and 100% covered in the non-AA case. |
| 155 | for (int i = 0; i < n; ++i) { |
| 156 | fEdges[3 * i + 2] += SK_ScalarHalf; |
| 157 | } |
| 158 | this->setWillReadFragmentPosition(); |
| 159 | } |
| 160 | |
| 161 | bool GrConvexPolyEffect::onIsEqual(const GrEffect& other) const { |
| 162 | const GrConvexPolyEffect& cpe = CastEffect<GrConvexPolyEffect>(other); |
| 163 | // ignore the fact that 0 == -0 and just use memcmp. |
| 164 | return (cpe.fEdgeType == fEdgeType && cpe.fEdgeCount == fEdgeCount && |
| 165 | 0 == memcmp(cpe.fEdges, fEdges, 3 * fEdgeCount * sizeof(SkScalar))); |
| 166 | } |
| 167 | |
| 168 | ////////////////////////////////////////////////////////////////////////////// |
| 169 | |
| 170 | GR_DEFINE_EFFECT_TEST(GrConvexPolyEffect); |
| 171 | |
| 172 | GrEffectRef* GrConvexPolyEffect::TestCreate(SkRandom* random, |
| 173 | GrContext*, |
| 174 | const GrDrawTargetCaps& caps, |
| 175 | GrTexture*[]) { |
| 176 | EdgeType edgeType = static_cast<EdgeType>(random->nextULessThan(kEdgeTypeCnt)); |
| 177 | int count = random->nextULessThan(kMaxEdges + 1); |
| 178 | SkScalar edges[kMaxEdges * 3]; |
| 179 | for (int i = 0; i < 3 * count; ++i) { |
| 180 | edges[i] = random->nextSScalar1(); |
| 181 | } |
| 182 | |
| 183 | return GrConvexPolyEffect::Create(edgeType, count, edges); |
| 184 | } |
| 185 | |