| /* |
| * Copyright 2013 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef GrBezierEffect_DEFINED |
| #define GrBezierEffect_DEFINED |
| |
| #include "GrCaps.h" |
| #include "GrProcessor.h" |
| #include "GrGeometryProcessor.h" |
| #include "GrTypesPriv.h" |
| |
| /** |
| * Shader is based off of Loop-Blinn Quadratic GPU Rendering |
| * The output of this effect is a hairline edge for conics. |
| * Conics specified by implicit equation K^2 - LM. |
| * K, L, and M, are the first three values of the vertex attribute, |
| * the fourth value is not used. Distance is calculated using a |
| * first order approximation from the taylor series. |
| * Coverage for AA is max(0, 1-distance). |
| * |
| * Test were also run using a second order distance approximation. |
| * There were two versions of the second order approx. The first version |
| * is of roughly the form: |
| * f(q) = |f(p)| - ||f'(p)||*||q-p|| - ||f''(p)||*||q-p||^2. |
| * The second is similar: |
| * f(q) = |f(p)| + ||f'(p)||*||q-p|| + ||f''(p)||*||q-p||^2. |
| * The exact version of the equations can be found in the paper |
| * "Distance Approximations for Rasterizing Implicit Curves" by Gabriel Taubin |
| * |
| * In both versions we solve the quadratic for ||q-p||. |
| * Version 1: |
| * gFM is magnitude of first partials and gFM2 is magnitude of 2nd partials (as derived from paper) |
| * builder->fsCodeAppend("\t\tedgeAlpha = (sqrt(gFM*gFM+4.0*func*gF2M) - gFM)/(2.0*gF2M);\n"); |
| * Version 2: |
| * builder->fsCodeAppend("\t\tedgeAlpha = (gFM - sqrt(gFM*gFM-4.0*func*gF2M))/(2.0*gF2M);\n"); |
| * |
| * Also note that 2nd partials of k,l,m are zero |
| * |
| * When comparing the two second order approximations to the first order approximations, |
| * the following results were found. Version 1 tends to underestimate the distances, thus it |
| * basically increases all the error that we were already seeing in the first order |
| * approx. So this version is not the one to use. Version 2 has the opposite effect |
| * and tends to overestimate the distances. This is much closer to what we are |
| * looking for. It is able to render ellipses (even thin ones) without the need to chop. |
| * However, it can not handle thin hyperbolas well and thus would still rely on |
| * chopping to tighten the clipping. Another side effect of the overestimating is |
| * that the curves become much thinner and "ropey". If all that was ever rendered |
| * were "not too thin" curves and ellipses then 2nd order may have an advantage since |
| * only one geometry would need to be rendered. However no benches were run comparing |
| * chopped first order and non chopped 2nd order. |
| */ |
| class GrGLConicEffect; |
| |
| class GrConicEffect : public GrGeometryProcessor { |
| public: |
| static sk_sp<GrGeometryProcessor> Make(GrColor color, |
| const SkMatrix& viewMatrix, |
| const GrPrimitiveEdgeType edgeType, |
| const GrCaps& caps, |
| const SkMatrix& localMatrix, |
| bool usesLocalCoords, |
| uint8_t coverage = 0xff) { |
| switch (edgeType) { |
| case kFillAA_GrProcessorEdgeType: |
| if (!caps.shaderCaps()->shaderDerivativeSupport()) { |
| return nullptr; |
| } |
| return sk_sp<GrGeometryProcessor>( |
| new GrConicEffect(color, viewMatrix, coverage, kFillAA_GrProcessorEdgeType, |
| localMatrix, usesLocalCoords)); |
| case kHairlineAA_GrProcessorEdgeType: |
| if (!caps.shaderCaps()->shaderDerivativeSupport()) { |
| return nullptr; |
| } |
| return sk_sp<GrGeometryProcessor>( |
| new GrConicEffect(color, viewMatrix, coverage, |
| kHairlineAA_GrProcessorEdgeType, localMatrix, |
| usesLocalCoords)); |
| case kFillBW_GrProcessorEdgeType: |
| return sk_sp<GrGeometryProcessor>( |
| new GrConicEffect(color, viewMatrix, coverage, kFillBW_GrProcessorEdgeType, |
| localMatrix, usesLocalCoords)); |
| default: |
| return nullptr; |
| } |
| } |
| |
| ~GrConicEffect() override; |
| |
| const char* name() const override { return "Conic"; } |
| |
| inline const Attribute* inPosition() const { return fInPosition; } |
| inline const Attribute* inConicCoeffs() const { return fInConicCoeffs; } |
| inline bool isAntiAliased() const { return GrProcessorEdgeTypeIsAA(fEdgeType); } |
| inline bool isFilled() const { return GrProcessorEdgeTypeIsFill(fEdgeType); } |
| inline GrPrimitiveEdgeType getEdgeType() const { return fEdgeType; } |
| GrColor color() const { return fColor; } |
| const SkMatrix& viewMatrix() const { return fViewMatrix; } |
| const SkMatrix& localMatrix() const { return fLocalMatrix; } |
| bool usesLocalCoords() const { return fUsesLocalCoords; } |
| uint8_t coverageScale() const { return fCoverageScale; } |
| |
| void getGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const override; |
| |
| GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const override; |
| |
| private: |
| GrConicEffect(GrColor, const SkMatrix& viewMatrix, uint8_t coverage, GrPrimitiveEdgeType, |
| const SkMatrix& localMatrix, bool usesLocalCoords); |
| |
| GrColor fColor; |
| SkMatrix fViewMatrix; |
| SkMatrix fLocalMatrix; |
| bool fUsesLocalCoords; |
| uint8_t fCoverageScale; |
| GrPrimitiveEdgeType fEdgeType; |
| const Attribute* fInPosition; |
| const Attribute* fInConicCoeffs; |
| |
| GR_DECLARE_GEOMETRY_PROCESSOR_TEST |
| |
| typedef GrGeometryProcessor INHERITED; |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| /** |
| * The output of this effect is a hairline edge for quadratics. |
| * Quadratic specified by 0=u^2-v canonical coords. u and v are the first |
| * two components of the vertex attribute. At the three control points that define |
| * the Quadratic, u, v have the values {0,0}, {1/2, 0}, and {1, 1} respectively. |
| * Coverage for AA is min(0, 1-distance). 3rd & 4th cimponent unused. |
| * Requires shader derivative instruction support. |
| */ |
| class GrGLQuadEffect; |
| |
| class GrQuadEffect : public GrGeometryProcessor { |
| public: |
| static sk_sp<GrGeometryProcessor> Make(GrColor color, |
| const SkMatrix& viewMatrix, |
| const GrPrimitiveEdgeType edgeType, |
| const GrCaps& caps, |
| const SkMatrix& localMatrix, |
| bool usesLocalCoords, |
| uint8_t coverage = 0xff) { |
| switch (edgeType) { |
| case kFillAA_GrProcessorEdgeType: |
| if (!caps.shaderCaps()->shaderDerivativeSupport()) { |
| return nullptr; |
| } |
| return sk_sp<GrGeometryProcessor>( |
| new GrQuadEffect(color, viewMatrix, coverage, kFillAA_GrProcessorEdgeType, |
| localMatrix, usesLocalCoords)); |
| case kHairlineAA_GrProcessorEdgeType: |
| if (!caps.shaderCaps()->shaderDerivativeSupport()) { |
| return nullptr; |
| } |
| return sk_sp<GrGeometryProcessor>( |
| new GrQuadEffect(color, viewMatrix, coverage, |
| kHairlineAA_GrProcessorEdgeType, localMatrix, |
| usesLocalCoords)); |
| case kFillBW_GrProcessorEdgeType: |
| return sk_sp<GrGeometryProcessor>( |
| new GrQuadEffect(color, viewMatrix, coverage, kFillBW_GrProcessorEdgeType, |
| localMatrix, usesLocalCoords)); |
| default: |
| return nullptr; |
| } |
| } |
| |
| ~GrQuadEffect() override; |
| |
| const char* name() const override { return "Quad"; } |
| |
| inline const Attribute* inPosition() const { return fInPosition; } |
| inline const Attribute* inHairQuadEdge() const { return fInHairQuadEdge; } |
| inline bool isAntiAliased() const { return GrProcessorEdgeTypeIsAA(fEdgeType); } |
| inline bool isFilled() const { return GrProcessorEdgeTypeIsFill(fEdgeType); } |
| inline GrPrimitiveEdgeType getEdgeType() const { return fEdgeType; } |
| GrColor color() const { return fColor; } |
| const SkMatrix& viewMatrix() const { return fViewMatrix; } |
| const SkMatrix& localMatrix() const { return fLocalMatrix; } |
| bool usesLocalCoords() const { return fUsesLocalCoords; } |
| uint8_t coverageScale() const { return fCoverageScale; } |
| |
| void getGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const override; |
| |
| GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const override; |
| |
| private: |
| GrQuadEffect(GrColor, const SkMatrix& viewMatrix, uint8_t coverage, GrPrimitiveEdgeType, |
| const SkMatrix& localMatrix, bool usesLocalCoords); |
| |
| GrColor fColor; |
| SkMatrix fViewMatrix; |
| SkMatrix fLocalMatrix; |
| bool fUsesLocalCoords; |
| uint8_t fCoverageScale; |
| GrPrimitiveEdgeType fEdgeType; |
| const Attribute* fInPosition; |
| const Attribute* fInHairQuadEdge; |
| |
| GR_DECLARE_GEOMETRY_PROCESSOR_TEST |
| |
| typedef GrGeometryProcessor INHERITED; |
| }; |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| /** |
| * Shader is based off of "Resolution Independent Curve Rendering using |
| * Programmable Graphics Hardware" by Loop and Blinn. |
| * The output of this effect is a hairline edge for non rational cubics. |
| * Cubics are specified by implicit equation K^3 - LM. |
| * K, L, and M, are the first three values of the vertex attribute, |
| * the fourth value is not used. Distance is calculated using a |
| * first order approximation from the taylor series. |
| * Coverage for AA is max(0, 1-distance). |
| */ |
| class GrGLCubicEffect; |
| |
| class GrCubicEffect : public GrGeometryProcessor { |
| public: |
| static sk_sp<GrGeometryProcessor> Make(GrColor color, |
| const SkMatrix& viewMatrix, |
| const SkMatrix& klm, |
| bool flipKL, |
| const GrPrimitiveEdgeType edgeType, |
| const GrCaps& caps) { |
| // Map KLM to something that operates in device space. |
| SkMatrix devKLM; |
| if (!viewMatrix.invert(&devKLM)) { |
| return nullptr; |
| } |
| devKLM.postConcat(klm); |
| if (flipKL) { |
| devKLM.postScale(-1, -1); |
| } |
| |
| switch (edgeType) { |
| case kFillAA_GrProcessorEdgeType: |
| return sk_sp<GrGeometryProcessor>( |
| new GrCubicEffect(color, viewMatrix, devKLM, kFillAA_GrProcessorEdgeType)); |
| case kHairlineAA_GrProcessorEdgeType: |
| return sk_sp<GrGeometryProcessor>( |
| new GrCubicEffect(color, viewMatrix, devKLM, kHairlineAA_GrProcessorEdgeType)); |
| case kFillBW_GrProcessorEdgeType: |
| return sk_sp<GrGeometryProcessor>( |
| new GrCubicEffect(color, viewMatrix, devKLM, kFillBW_GrProcessorEdgeType)); |
| default: |
| return nullptr; |
| } |
| } |
| |
| ~GrCubicEffect() override; |
| |
| const char* name() const override { return "Cubic"; } |
| |
| inline const Attribute* inPosition() const { return fInPosition; } |
| inline bool isAntiAliased() const { return GrProcessorEdgeTypeIsAA(fEdgeType); } |
| inline bool isFilled() const { return GrProcessorEdgeTypeIsFill(fEdgeType); } |
| inline GrPrimitiveEdgeType getEdgeType() const { return fEdgeType; } |
| GrColor color() const { return fColor; } |
| bool colorIgnored() const { return GrColor_ILLEGAL == fColor; } |
| const SkMatrix& viewMatrix() const { return fViewMatrix; } |
| const SkMatrix& devKLMMatrix() const { return fDevKLMMatrix; } |
| |
| void getGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const override; |
| |
| GrGLSLPrimitiveProcessor* createGLSLInstance(const GrShaderCaps&) const override; |
| |
| private: |
| GrCubicEffect(GrColor, const SkMatrix& viewMatrix, const SkMatrix& devKLMMatrix, |
| GrPrimitiveEdgeType); |
| |
| GrColor fColor; |
| SkMatrix fViewMatrix; |
| SkMatrix fDevKLMMatrix; |
| GrPrimitiveEdgeType fEdgeType; |
| const Attribute* fInPosition; |
| |
| GR_DECLARE_GEOMETRY_PROCESSOR_TEST |
| |
| typedef GrGeometryProcessor INHERITED; |
| }; |
| |
| #endif |
