1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
|
/*
* 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 GrCCPRQuadraticShader_DEFINED
#define GrCCPRQuadraticShader_DEFINED
#include "ccpr/GrCCPRCoverageProcessor.h"
/**
* This class renders the coverage of closed quadratic curves 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 curves must be monotonic with respect to the vector of their closing edge [P2 - P0].
* (Use GrCCPRGeometry.)
*/
class GrCCPRQuadraticShader : public GrCCPRCoverageProcessor::Shader {
protected:
int getNumInputPoints() const final { return 3; }
void appendInputPointFetch(const GrCCPRCoverageProcessor&, GrGLSLShaderBuilder*,
const TexelBufferHandle& pointsBuffer,
const char* pointId) const override;
void emitWind(GrGLSLShaderBuilder*, const char* pts, const char* outputWind) const final;
void emitSetupCode(GrGLSLShaderBuilder*, const char* pts, const char* segmentId,
const char* wind, GeometryVars*) const final;
virtual void onEmitSetupCode(GrGLSLShaderBuilder*, const char* pts, const char* segmentId,
GeometryVars*) const = 0;
WindHandling onEmitVaryings(GrGLSLVaryingHandler*, SkString* code, const char* position,
const char* coverage, const char* wind) final;
virtual void onEmitVaryings(GrGLSLVaryingHandler*, SkString* code) = 0;
const GrShaderVar fCanonicalMatrix{"canonical_matrix", kFloat3x3_GrSLType};
const GrShaderVar fEdgeDistanceEquation{"edge_distance_equation", kFloat3_GrSLType};
GrGLSLGeoToFrag fXYD{kFloat3_GrSLType};
};
/**
* This pass draws a conservative raster hull around the quadratic bezier curve, computes the
* curve's coverage using the gradient-based AA technique outlined in the Loop/Blinn paper, and
* uses simple distance-to-edge to subtract out coverage for the flat closing edge [P2 -> P0]. Since
* the provided curves are monotonic, this will get every pixel right except the two corners.
*/
class GrCCPRQuadraticHullShader : public GrCCPRQuadraticShader {
int getNumSegments() const final { return 4; } // 4 wedges.
GeometryType getGeometryType() const override { return GeometryType::kHull; }
void onEmitSetupCode(GrGLSLShaderBuilder*, const char* pts, const char* wedgeId,
GeometryVars*) const override;
void onEmitVaryings(GrGLSLVaryingHandler*, SkString* code) override;
void onEmitFragmentCode(GrGLSLPPFragmentBuilder*, const char* outputCoverage) const override;
GrGLSLGeoToFrag fGrad{kFloat2_GrSLType};
};
/**
* This pass fixes the corners of a closed quadratic segment with soft MSAA.
*/
class GrCCPRQuadraticCornerShader : public GrCCPRQuadraticShader {
int getNumSegments() const final { return 2; } // 2 corners.
GeometryType getGeometryType() const override { return GeometryType::kCorners; }
void onEmitSetupCode(GrGLSLShaderBuilder*, const char* pts, const char* cornerId,
GeometryVars*) const override;
void onEmitVaryings(GrGLSLVaryingHandler*, SkString* code) override;
void onEmitFragmentCode(GrGLSLPPFragmentBuilder*, const char* outputCoverage) const override;
GrGLSLGeoToFrag fdXYDdx{kFloat3_GrSLType};
GrGLSLGeoToFrag fdXYDdy{kFloat3_GrSLType};
};
#endif
|
