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
|
/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkEmbossMask.h"
#include "SkMath.h"
static inline int nonzero_to_one(int x) {
#if 0
return x != 0;
#else
return ((unsigned)(x | -x)) >> 31;
#endif
}
static inline int neq_to_one(int x, int max) {
#if 0
return x != max;
#else
SkASSERT(x >= 0 && x <= max);
return ((unsigned)(x - max)) >> 31;
#endif
}
static inline int neq_to_mask(int x, int max) {
#if 0
return -(x != max);
#else
SkASSERT(x >= 0 && x <= max);
return (x - max) >> 31;
#endif
}
static inline unsigned div255(unsigned x) {
SkASSERT(x <= (255*255));
return x * ((1 << 24) / 255) >> 24;
}
#define kDelta 32 // small enough to show off angle differences
#include "SkEmbossMask_Table.h"
#if defined(SK_BUILD_FOR_WIN32) && defined(SK_DEBUG)
#include <stdio.h>
void SkEmbossMask_BuildTable() {
// build it 0..127 x 0..127, so we use 2^15 - 1 in the numerator for our "fixed" table
FILE* file = ::fopen("SkEmbossMask_Table.h", "w");
SkASSERT(file);
::fprintf(file, "#include \"SkTypes.h\"\n\n");
::fprintf(file, "static const U16 gInvSqrtTable[128 * 128] = {\n");
for (int dx = 0; dx <= 255/2; dx++) {
for (int dy = 0; dy <= 255/2; dy++) {
if ((dy & 15) == 0)
::fprintf(file, "\t");
uint16_t value = SkToU16((1 << 15) / SkSqrt32(dx * dx + dy * dy + kDelta*kDelta/4));
::fprintf(file, "0x%04X", value);
if (dx * 128 + dy < 128*128-1) {
::fprintf(file, ", ");
}
if ((dy & 15) == 15) {
::fprintf(file, "\n");
}
}
}
::fprintf(file, "};\n#define kDeltaUsedToBuildTable\t%d\n", kDelta);
::fclose(file);
}
#endif
void SkEmbossMask::Emboss(SkMask* mask, const SkEmbossMaskFilter::Light& light) {
SkASSERT(kDelta == kDeltaUsedToBuildTable);
SkASSERT(mask->fFormat == SkMask::k3D_Format);
int specular = light.fSpecular;
int ambient = light.fAmbient;
SkFixed lx = SkScalarToFixed(light.fDirection[0]);
SkFixed ly = SkScalarToFixed(light.fDirection[1]);
SkFixed lz = SkScalarToFixed(light.fDirection[2]);
SkFixed lz_dot_nz = lz * kDelta;
int lz_dot8 = lz >> 8;
size_t planeSize = mask->computeImageSize();
uint8_t* alpha = mask->fImage;
uint8_t* multiply = (uint8_t*)alpha + planeSize;
uint8_t* additive = multiply + planeSize;
int rowBytes = mask->fRowBytes;
int maxy = mask->fBounds.height() - 1;
int maxx = mask->fBounds.width() - 1;
int prev_row = 0;
for (int y = 0; y <= maxy; y++) {
int next_row = neq_to_mask(y, maxy) & rowBytes;
for (int x = 0; x <= maxx; x++) {
if (alpha[x]) {
int nx = alpha[x + neq_to_one(x, maxx)] - alpha[x - nonzero_to_one(x)];
int ny = alpha[x + next_row] - alpha[x - prev_row];
SkFixed numer = lx * nx + ly * ny + lz_dot_nz;
int mul = ambient;
int add = 0;
if (numer > 0) { // preflight when numer/denom will be <= 0
#if 0
int denom = SkSqrt32(nx * nx + ny * ny + kDelta*kDelta);
SkFixed dot = numer / denom;
dot >>= 8; // now dot is 2^8 instead of 2^16
#else
// can use full numer, but then we need to call SkFixedMul, since
// numer is 24 bits, and our table is 12 bits
// SkFixed dot = SkFixedMul(numer, gTable[]) >> 8
SkFixed dot = (unsigned)(numer >> 4) * gInvSqrtTable[(SkAbs32(nx) >> 1 << 7) | (SkAbs32(ny) >> 1)] >> 20;
#endif
mul = SkFastMin32(mul + dot, 255);
// now for the reflection
// R = 2 (Light * Normal) Normal - Light
// hilite = R * Eye(0, 0, 1)
int hilite = (2 * dot - lz_dot8) * lz_dot8 >> 8;
if (hilite > 0) {
// pin hilite to 255, since our fast math is also a little sloppy
hilite = SkClampMax(hilite, 255);
// specular is 4.4
// would really like to compute the fractional part of this
// and then possibly cache a 256 table for a given specular
// value in the light, and just pass that in to this function.
add = hilite;
for (int i = specular >> 4; i > 0; --i) {
add = div255(add * hilite);
}
}
}
multiply[x] = SkToU8(mul);
additive[x] = SkToU8(add);
// multiply[x] = 0xFF;
// additive[x] = 0;
// ((uint8_t*)alpha)[x] = alpha[x] * multiply[x] >> 8;
}
}
alpha += rowBytes;
multiply += rowBytes;
additive += rowBytes;
prev_row = rowBytes;
}
}
|
