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
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
|
/*
* Copyright (C) 2010 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#if ENABLE(ACCELERATED_2D_CANVAS)
#include "LoopBlinnTextureCoords.h"
#include <math.h>
#include <wtf/Assertions.h>
namespace WebCore {
LoopBlinnTextureCoords::Result LoopBlinnTextureCoords::compute(const LoopBlinnClassifier::Result& classification, LoopBlinnConstants::FillSide sideToFill)
{
// Loop and Blinn's formulation states that the right side of the
// curve is defined to be the inside (filled region), but for some
// reason it looks like with the default orientation parameters we
// are filling the left side of the curve. Regardless, because we
// can receive arbitrarily oriented curves as input, we might have
// to reverse the orientation of the cubic texture coordinates even
// in cases where the paper doesn't say it is necessary.
bool reverseOrientation = false;
static const float OneThird = 1.0f / 3.0f;
static const float TwoThirds = 2.0f / 3.0f;
LoopBlinnClassifier::CurveType curveType = classification.curveType;
LoopBlinnTextureCoords::Result result;
switch (curveType) {
case LoopBlinnClassifier::kSerpentine: {
float t1 = sqrtf(9.0f * classification.d2 * classification.d2 - 12 * classification.d1 * classification.d3);
float ls = 3.0f * classification.d2 - t1;
float lt = 6.0f * classification.d1;
float ms = 3.0f * classification.d2 + t1;
float mt = lt;
float ltMinusLs = lt - ls;
float mtMinusMs = mt - ms;
result.klmCoordinates[0] = FloatPoint3D(ls * ms,
ls * ls * ls,
ms * ms * ms);
result.klmCoordinates[1] = FloatPoint3D(OneThird * (3.0f * ls * ms - ls * mt - lt * ms),
ls * ls * (ls - lt),
ms * ms * (ms - mt));
result.klmCoordinates[2] = FloatPoint3D(OneThird * (lt * (mt - 2.0f * ms) + ls * (3.0f * ms - 2.0f * mt)),
ltMinusLs * ltMinusLs * ls,
mtMinusMs * mtMinusMs * ms);
result.klmCoordinates[3] = FloatPoint3D(ltMinusLs * mtMinusMs,
-(ltMinusLs * ltMinusLs * ltMinusLs),
-(mtMinusMs * mtMinusMs * mtMinusMs));
if (classification.d1 < 0.0f)
reverseOrientation = true;
break;
}
case LoopBlinnClassifier::kLoop: {
float t1 = sqrtf(4.0f * classification.d1 * classification.d3 - 3.0f * classification.d2 * classification.d2);
float ls = classification.d2 - t1;
float lt = 2.0f * classification.d1;
float ms = classification.d2 + t1;
float mt = lt;
// Figure out whether there is a rendering artifact requiring
// the curve to be subdivided by the caller.
float ql = ls / lt;
float qm = ms / mt;
if (0.0f < ql && ql < 1.0f) {
result.hasRenderingArtifact = true;
result.subdivisionParameterValue = ql;
return result;
}
if (0.0f < qm && qm < 1.0f) {
result.hasRenderingArtifact = true;
result.subdivisionParameterValue = qm;
return result;
}
float ltMinusLs = lt - ls;
float mtMinusMs = mt - ms;
result.klmCoordinates[0] = FloatPoint3D(ls * ms,
ls * ls * ms,
ls * ms * ms);
result.klmCoordinates[1] = FloatPoint3D(OneThird * (-ls * mt - lt * ms + 3.0f * ls * ms),
-OneThird * ls * (ls * (mt - 3.0f * ms) + 2.0f * lt * ms),
-OneThird * ms * (ls * (2.0f * mt - 3.0f * ms) + lt * ms));
result.klmCoordinates[2] = FloatPoint3D(OneThird * (lt * (mt - 2.0f * ms) + ls * (3.0f * ms - 2.0f * mt)),
OneThird * (lt - ls) * (ls * (2.0f * mt - 3.0f * ms) + lt * ms),
OneThird * (mt - ms) * (ls * (mt - 3.0f * ms) + 2.0f * lt * ms));
result.klmCoordinates[3] = FloatPoint3D(ltMinusLs * mtMinusMs,
-(ltMinusLs * ltMinusLs) * mtMinusMs,
-ltMinusLs * mtMinusMs * mtMinusMs);
reverseOrientation = ((classification.d1 > 0.0f && result.klmCoordinates[0].x() < 0.0f)
|| (classification.d1 < 0.0f && result.klmCoordinates[0].x() > 0.0f));
break;
}
case LoopBlinnClassifier::kCusp: {
float ls = classification.d3;
float lt = 3.0f * classification.d2;
float lsMinusLt = ls - lt;
result.klmCoordinates[0] = FloatPoint3D(ls,
ls * ls * ls,
1.0f);
result.klmCoordinates[1] = FloatPoint3D(ls - OneThird * lt,
ls * ls * lsMinusLt,
1.0f);
result.klmCoordinates[2] = FloatPoint3D(ls - TwoThirds * lt,
lsMinusLt * lsMinusLt * ls,
1.0f);
result.klmCoordinates[3] = FloatPoint3D(lsMinusLt,
lsMinusLt * lsMinusLt * lsMinusLt,
1.0f);
break;
}
case LoopBlinnClassifier::kQuadratic: {
result.klmCoordinates[0] = FloatPoint3D(0, 0, 0);
result.klmCoordinates[1] = FloatPoint3D(OneThird, 0, OneThird);
result.klmCoordinates[2] = FloatPoint3D(TwoThirds, OneThird, TwoThirds);
result.klmCoordinates[3] = FloatPoint3D(1, 1, 1);
if (classification.d3 < 0)
reverseOrientation = true;
break;
}
case LoopBlinnClassifier::kLine:
case LoopBlinnClassifier::kPoint:
result.isLineOrPoint = true;
break;
default:
ASSERT_NOT_REACHED();
break;
}
if (sideToFill == LoopBlinnConstants::RightSide)
reverseOrientation = !reverseOrientation;
if (reverseOrientation) {
for (int i = 0; i < 4; ++i) {
result.klmCoordinates[i].setX(-result.klmCoordinates[i].x());
result.klmCoordinates[i].setY(-result.klmCoordinates[i].y());
}
}
return result;
}
} // namespace WebCore
#endif
|
