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
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
/*
* 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 GrCCPRQuadraticProcessor_DEFINED
#define GrCCPRQuadraticProcessor_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 GrCCPRQuadraticProcessor : public GrCCPRCoverageProcessor::PrimitiveProcessor {
public:
GrCCPRQuadraticProcessor()
: INHERITED(CoverageType::kShader)
, fCanonicalMatrix("canonical_matrix", kMat33f_GrSLType, GrShaderVar::kNonArray,
kHigh_GrSLPrecision)
, fCanonicalDerivatives("canonical_derivatives", kMat22f_GrSLType,
GrShaderVar::kNonArray, kHigh_GrSLPrecision)
, fEdgeDistanceEquation("edge_distance_equation", kVec3f_GrSLType,
GrShaderVar::kNonArray, kHigh_GrSLPrecision)
, fXYD(kVec3f_GrSLType) {}
void resetVaryings(GrGLSLVaryingHandler* varyingHandler) override {
varyingHandler->addVarying("xyd", &fXYD, kHigh_GrSLPrecision);
}
void onEmitVertexShader(const GrCCPRCoverageProcessor&, GrGLSLVertexBuilder*,
const TexelBufferHandle& pointsBuffer, const char* atlasOffset,
const char* rtAdjust, GrGPArgs*) const override;
void emitWind(GrGLSLGeometryBuilder*, const char* rtAdjust, const char* outputWind) const final;
void onEmitGeometryShader(GrGLSLGeometryBuilder*, const char* emitVertexFn, const char* wind,
const char* rtAdjust) const final;
void emitPerVertexGeometryCode(SkString* fnBody, const char* position, const char* coverage,
const char* wind) const final;
protected:
virtual void emitQuadraticGeometry(GrGLSLGeometryBuilder*, const char* emitVertexFn,
const char* rtAdjust) const = 0;
virtual void onEmitPerVertexGeometryCode(SkString* fnBody) const = 0;
GrShaderVar fCanonicalMatrix;
GrShaderVar fCanonicalDerivatives;
GrShaderVar fEdgeDistanceEquation;
GrGLSLGeoToFrag fXYD;
typedef GrCCPRCoverageProcessor::PrimitiveProcessor INHERITED;
};
/**
* 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 GrCCPRQuadraticHullProcessor : public GrCCPRQuadraticProcessor {
public:
GrCCPRQuadraticHullProcessor()
: fGradXY(kVec2f_GrSLType) {}
void resetVaryings(GrGLSLVaryingHandler* varyingHandler) override {
this->INHERITED::resetVaryings(varyingHandler);
varyingHandler->addVarying("grad_xy", &fGradXY, kHigh_GrSLPrecision);
}
void emitQuadraticGeometry(GrGLSLGeometryBuilder*, const char* emitVertexFn,
const char* rtAdjust) const override;
void onEmitPerVertexGeometryCode(SkString* fnBody) const override;
void emitShaderCoverage(GrGLSLFragmentBuilder* f, const char* outputCoverage) const override;
private:
GrGLSLGeoToFrag fGradXY;
typedef GrCCPRQuadraticProcessor INHERITED;
};
/**
* This pass fixes the corners of a closed quadratic segment with soft MSAA.
*/
class GrCCPRQuadraticCornerProcessor : public GrCCPRQuadraticProcessor {
public:
GrCCPRQuadraticCornerProcessor()
: fEdgeDistanceDerivatives("edge_distance_derivatives", kVec2f_GrSLType,
GrShaderVar::kNonArray, kHigh_GrSLPrecision)
, fdXYDdx(kVec3f_GrSLType)
, fdXYDdy(kVec3f_GrSLType) {}
void resetVaryings(GrGLSLVaryingHandler* varyingHandler) override {
this->INHERITED::resetVaryings(varyingHandler);
varyingHandler->addFlatVarying("dXYDdx", &fdXYDdx, kHigh_GrSLPrecision);
varyingHandler->addFlatVarying("dXYDdy", &fdXYDdy, kHigh_GrSLPrecision);
}
void emitQuadraticGeometry(GrGLSLGeometryBuilder*, const char* emitVertexFn,
const char* rtAdjust) const override;
void onEmitPerVertexGeometryCode(SkString* fnBody) const override;
void emitShaderCoverage(GrGLSLFragmentBuilder*, const char* outputCoverage) const override;
private:
GrShaderVar fEdgeDistanceDerivatives;
GrGLSLGeoToFrag fdXYDdx;
GrGLSLGeoToFrag fdXYDdy;
typedef GrCCPRQuadraticProcessor INHERITED;
};
#endif
|
