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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrCCCubicShader_DEFINED
#define GrCCCubicShader_DEFINED
#include "ccpr/GrCCCoverageProcessor.h"
/**
* This class renders the coverage of convex closed cubic segments using the techniques outlined in
* "Resolution Independent Curve Rendering using Programmable Graphics Hardware" by Charles Loop and
* Jim Blinn:
*
* https://www.microsoft.com/en-us/research/wp-content/uploads/2005/01/p1000-loop.pdf
*
* The provided curve segments must be convex, monotonic with respect to the vector of their closing
* edge [P3 - P0], and must not contain or be near any inflection points or loop intersections.
* (Use GrCCGeometry.)
*/
class GrCCCubicShader : public GrCCCoverageProcessor::Shader {
protected:
void emitSetupCode(GrGLSLVertexGeoBuilder*, const char* pts, const char* repetitionID,
const char* wind, GeometryVars*) const final;
virtual void onEmitSetupCode(GrGLSLVertexGeoBuilder*, const char* pts, const char* repetitionID,
GeometryVars*) const {}
void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code,
const char* position, const char* inputCoverage, const char* wind) final;
virtual void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code) = 0;
void onEmitFragmentCode(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const final;
virtual void emitCoverage(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const = 0;
GrShaderVar fKLMMatrix{"klm_matrix", kFloat3x3_GrSLType};
GrShaderVar fEdgeDistanceEquation{"edge_distance_equation", kFloat3_GrSLType};
GrGLSLVarying fKLMD;
};
class GrCCCubicHullShader : public GrCCCubicShader {
void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code) override;
void emitCoverage(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const override;
GrGLSLVarying fGradMatrix;
};
class GrCCCubicCornerShader : public GrCCCubicShader {
void onEmitSetupCode(GrGLSLVertexGeoBuilder*, const char* pts, const char* repetitionID,
GeometryVars*) const override;
void onEmitVaryings(GrGLSLVaryingHandler*, GrGLSLVarying::Scope, SkString* code) override;
void emitCoverage(GrGLSLFPFragmentBuilder*, const char* outputCoverage) const override;
GrGLSLVarying fdKLMDdx;
GrGLSLVarying fdKLMDdy;
};
#endif
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