1 /* 2 * Copyright 2017 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 #ifndef GrCCCubicShader_DEFINED 9 #define GrCCCubicShader_DEFINED 10 11 #include "ccpr/GrCCCoverageProcessor.h" 12 13 /** 14 * This class renders the coverage of convex closed cubic segments using the techniques outlined in 15 * "Resolution Independent Curve Rendering using Programmable Graphics Hardware" by Charles Loop and 16 * Jim Blinn: 17 * 18 * https://www.microsoft.com/en-us/research/wp-content/uploads/2005/01/p1000-loop.pdf 19 * 20 * The provided curve segments must be convex, monotonic with respect to the vector of their closing 21 * edge [P3 - P0], and must not contain or be near any inflection points or loop intersections. 22 * (Use GrCCGeometry.) 23 */ 24 class GrCCCubicShader : public GrCCCoverageProcessor::Shader { 25 protected: 26 void emitSetupCode(GrGLSLVertexGeoBuilder*, const char* pts, const char* repetitionID, 27 const char* wind, GeometryVars*) const final; onEmitSetupCode(GrGLSLVertexGeoBuilder *,const char * pts,const char * repetitionID,GeometryVars *)28 virtual void onEmitSetupCode(GrGLSLVertexGeoBuilder*, const char* pts, const char* repetitionID, 29 GeometryVars*) const {} 30 31 void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code, 32 const char* position, const char* inputCoverage, const char* wind) final; 33 virtual void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code) = 0; 34 35 void onEmitFragmentCode(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const final; 36 virtual void emitCoverage(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const = 0; 37 38 GrShaderVar fKLMMatrix{"klm_matrix", kFloat3x3_GrSLType}; 39 GrShaderVar fEdgeDistanceEquation{"edge_distance_equation", kFloat3_GrSLType}; 40 GrGLSLVarying fKLMD; 41 }; 42 43 class GrCCCubicHullShader : public GrCCCubicShader { 44 void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code) override; 45 void emitCoverage(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const override; 46 47 GrGLSLVarying fGradMatrix; 48 }; 49 50 class GrCCCubicCornerShader : public GrCCCubicShader { 51 void onEmitSetupCode(GrGLSLVertexGeoBuilder*, const char* pts, const char* repetitionID, 52 GeometryVars*) const override; 53 void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code) override; 54 void emitCoverage(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const override; 55 56 GrGLSLVarying fdKLMDdx; 57 GrGLSLVarying fdKLMDdy; 58 }; 59 60 #endif 61