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comparison: gfx/skia/trunk/src/gpu/effects/GrDistanceFieldTextureEffect.cpp
gfx/skia/trunk/src/gpu/effects/GrDistanceFieldTextureEffect.cpp
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:05263a8db3d2 |
|---|---|
| 1 /* | |
| 2 * Copyright 2013 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 "GrDistanceFieldTextureEffect.h" | |
| 9 #include "gl/GrGLEffect.h" | |
| 10 #include "gl/GrGLSL.h" | |
| 11 #include "gl/GrGLTexture.h" | |
| 12 #include "gl/GrGLVertexEffect.h" | |
| 13 #include "GrTBackendEffectFactory.h" | |
| 14 #include "GrTexture.h" | |
| 15 | |
| 16 // The distance field is constructed as unsigned char values, so that the zero value is at 128, | |
| 17 // and the range is [-4, 4 - 1/255). Hence our multiplier is 8 - 1/32 and zero threshold is 128/255. | |
| 18 #define MULTIPLIER "7.96875" | |
| 19 #define THRESHOLD "0.50196078431" | |
| 20 | |
| 21 class GrGLDistanceFieldTextureEffect : public GrGLVertexEffect { | |
| 22 public: | |
| 23 GrGLDistanceFieldTextureEffect(const GrBackendEffectFactory& factory, | |
| 24 const GrDrawEffect& drawEffect) | |
| 25 : INHERITED (factory) | |
| 26 , fTextureSize(SkSize::Make(-1.f,-1.f)) {} | |
| 27 | |
| 28 virtual void emitCode(GrGLFullShaderBuilder* builder, | |
| 29 const GrDrawEffect& drawEffect, | |
| 30 EffectKey key, | |
| 31 const char* outputColor, | |
| 32 const char* inputColor, | |
| 33 const TransformedCoordsArray&, | |
| 34 const TextureSamplerArray& samplers) SK_OVERRIDE { | |
| 35 SkASSERT(1 == drawEffect.castEffect<GrDistanceFieldTextureEffect>().numVertexAttribs()); | |
| 36 | |
| 37 SkAssertResult(builder->enableFeature(GrGLShaderBuilder::kStandardDerivatives_GLSLFeature)); | |
| 38 | |
| 39 SkString fsCoordName; | |
| 40 const char* vsCoordName; | |
| 41 const char* fsCoordNamePtr; | |
| 42 builder->addVarying(kVec2f_GrSLType, "textureCoords", &vsCoordName, &fsCoordNamePtr); | |
| 43 fsCoordName = fsCoordNamePtr; | |
| 44 | |
| 45 const char* attrName0 = | |
| 46 builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0])->c_str(); | |
| 47 builder->vsCodeAppendf("\t%s = %s;\n", vsCoordName, attrName0); | |
| 48 | |
| 49 const char* textureSizeUniName = NULL; | |
| 50 fTextureSizeUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility, | |
| 51 kVec2f_GrSLType, "TextureSize", | |
| 52 &textureSizeUniName); | |
| 53 | |
| 54 builder->fsCodeAppend("\tvec4 texColor = "); | |
| 55 builder->fsAppendTextureLookup(samplers[0], | |
| 56 fsCoordName.c_str(), | |
| 57 kVec2f_GrSLType); | |
| 58 builder->fsCodeAppend(";\n"); | |
| 59 builder->fsCodeAppend("\tfloat distance = " MULTIPLIER "*(texColor.r - " THRESHOLD ");\n"); | |
| 60 | |
| 61 // we adjust for the effect of the transformation on the distance by using | |
| 62 // the length of the gradient of the texture coordinates. We use st coordinates | |
| 63 // to ensure we're mapping 1:1 from texel space to pixel space. | |
| 64 builder->fsCodeAppendf("\tvec2 st = %s*%s;\n", fsCoordName.c_str(), textureSizeUniName); | |
| 65 builder->fsCodeAppend("\tvec2 Jdx = dFdx(st);\n"); | |
| 66 builder->fsCodeAppend("\tvec2 Jdy = dFdy(st);\n"); | |
| 67 builder->fsCodeAppend("\tvec2 st_grad = normalize(st);\n"); | |
| 68 builder->fsCodeAppend("\tvec2 grad = vec2(st_grad.x*Jdx.x + st_grad.y*Jdy.x,\n"); | |
| 69 builder->fsCodeAppend("\t st_grad.x*Jdx.y + st_grad.y*Jdy.y);\n"); | |
| 70 | |
| 71 // this gives us a smooth step across approximately one fragment | |
| 72 // (assuming a radius of the diagonal of the fragment, hence a factor of sqrt(2)/2) | |
| 73 builder->fsCodeAppend("\tfloat afwidth = 0.7071*length(grad);\n"); | |
| 74 builder->fsCodeAppend("\tfloat val = smoothstep(-afwidth, afwidth, distance);\n"); | |
| 75 | |
| 76 builder->fsCodeAppendf("\t%s = %s;\n", outputColor, | |
| 77 (GrGLSLExpr4(inputColor) * GrGLSLExpr1("val")).c_str()); | |
| 78 } | |
| 79 | |
| 80 virtual void setData(const GrGLUniformManager& uman, | |
| 81 const GrDrawEffect& drawEffect) SK_OVERRIDE { | |
| 82 SkASSERT(fTextureSizeUni.isValid()); | |
| 83 const GrDistanceFieldTextureEffect& distanceFieldEffect = | |
| 84 drawEffect.castEffect<GrDistanceFieldTextureEffect>(); | |
| 85 if (distanceFieldEffect.getSize().width() != fTextureSize.width() || | |
| 86 distanceFieldEffect.getSize().height() != fTextureSize.height()) { | |
| 87 fTextureSize = distanceFieldEffect.getSize(); | |
| 88 uman.set2f(fTextureSizeUni, | |
| 89 distanceFieldEffect.getSize().width(), | |
| 90 distanceFieldEffect.getSize().height()); | |
| 91 } | |
| 92 } | |
| 93 | |
| 94 private: | |
| 95 GrGLUniformManager::UniformHandle fTextureSizeUni; | |
| 96 SkSize fTextureSize; | |
| 97 | |
| 98 typedef GrGLVertexEffect INHERITED; | |
| 99 }; | |
| 100 | |
| 101 /////////////////////////////////////////////////////////////////////////////// | |
| 102 | |
| 103 GrDistanceFieldTextureEffect::GrDistanceFieldTextureEffect(GrTexture* texture, | |
| 104 const GrTextureParams& params, | |
| 105 const SkISize& size) | |
| 106 : fTextureAccess(texture, params) | |
| 107 , fSize(SkSize::Make(SkIntToScalar(size.width()), SkIntToScalar(size.height()))) { | |
| 108 this->addTextureAccess(&fTextureAccess); | |
| 109 this->addVertexAttrib(kVec2f_GrSLType); | |
| 110 } | |
| 111 | |
| 112 bool GrDistanceFieldTextureEffect::onIsEqual(const GrEffect& other) const { | |
| 113 const GrDistanceFieldTextureEffect& cte = CastEffect<GrDistanceFieldTextureEffect>(other); | |
| 114 return fTextureAccess == cte.fTextureAccess; | |
| 115 } | |
| 116 | |
| 117 void GrDistanceFieldTextureEffect::getConstantColorComponents(GrColor* color, | |
| 118 uint32_t* validFlags) const { | |
| 119 if ((*validFlags & kA_GrColorComponentFlag) && 0xFF == GrColorUnpackA(*color) && | |
| 120 GrPixelConfigIsOpaque(this->texture(0)->config())) { | |
| 121 *validFlags = kA_GrColorComponentFlag; | |
| 122 } else { | |
| 123 *validFlags = 0; | |
| 124 } | |
| 125 } | |
| 126 | |
| 127 const GrBackendEffectFactory& GrDistanceFieldTextureEffect::getFactory() const { | |
| 128 return GrTBackendEffectFactory<GrDistanceFieldTextureEffect>::getInstance(); | |
| 129 } | |
| 130 | |
| 131 /////////////////////////////////////////////////////////////////////////////// | |
| 132 | |
| 133 GR_DEFINE_EFFECT_TEST(GrDistanceFieldTextureEffect); | |
| 134 | |
| 135 GrEffectRef* GrDistanceFieldTextureEffect::TestCreate(SkRandom* random, | |
| 136 GrContext*, | |
| 137 const GrDrawTargetCaps&, | |
| 138 GrTexture* textures[]) { | |
| 139 int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx : | |
| 140 GrEffectUnitTest::kAlphaTextureIdx; | |
| 141 static const SkShader::TileMode kTileModes[] = { | |
| 142 SkShader::kClamp_TileMode, | |
| 143 SkShader::kRepeat_TileMode, | |
| 144 SkShader::kMirror_TileMode, | |
| 145 }; | |
| 146 SkShader::TileMode tileModes[] = { | |
| 147 kTileModes[random->nextULessThan(SK_ARRAY_COUNT(kTileModes))], | |
| 148 kTileModes[random->nextULessThan(SK_ARRAY_COUNT(kTileModes))], | |
| 149 }; | |
| 150 GrTextureParams params(tileModes, random->nextBool() ? GrTextureParams::kBilerp_FilterMode : | |
| 151 GrTextureParams::kNone_FilterMode); | |
| 152 SkISize size = SkISize::Make(1024, 2048); | |
| 153 | |
| 154 return GrDistanceFieldTextureEffect::Create(textures[texIdx], params, size); | |
| 155 } |
