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
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkEndian.h"
#include "SkColorPriv.h"
#include "SkImageDecoder.h"
#include "SkScaledBitmapSampler.h"
#include "SkStream.h"
#include "SkStreamPriv.h"
#include "SkTypes.h"
#include "SkTextureCompressor.h"
class SkASTCImageDecoder : public SkImageDecoder {
public:
SkASTCImageDecoder() { }
Format getFormat() const override {
return kASTC_Format;
}
protected:
Result onDecode(SkStream* stream, SkBitmap* bm, Mode) override;
private:
typedef SkImageDecoder INHERITED;
};
/////////////////////////////////////////////////////////////////////////////////////////
static const uint32_t kASTCMagicNumber = 0x5CA1AB13;
static inline int read_24bit(const uint8_t* buf) {
// Assume everything is little endian...
return
static_cast<int>(buf[0]) |
(static_cast<int>(buf[1]) << 8) |
(static_cast<int>(buf[2]) << 16);
}
SkImageDecoder::Result SkASTCImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
SkAutoMalloc autoMal;
const size_t length = SkCopyStreamToStorage(&autoMal, stream);
if (0 == length) {
return kFailure;
}
unsigned char* buf = (unsigned char*)autoMal.get();
// Make sure that the magic header is there...
SkASSERT(SkEndian_SwapLE32(*(reinterpret_cast<uint32_t*>(buf))) == kASTCMagicNumber);
// Advance past the magic header
buf += 4;
const int blockDimX = buf[0];
const int blockDimY = buf[1];
const int blockDimZ = buf[2];
if (1 != blockDimZ) {
// We don't support decoding 3D
return kFailure;
}
// Choose the proper ASTC format
SkTextureCompressor::Format astcFormat;
if (4 == blockDimX && 4 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_4x4_Format;
} else if (5 == blockDimX && 4 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_5x4_Format;
} else if (5 == blockDimX && 5 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_5x5_Format;
} else if (6 == blockDimX && 5 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_6x5_Format;
} else if (6 == blockDimX && 6 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_6x6_Format;
} else if (8 == blockDimX && 5 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_8x5_Format;
} else if (8 == blockDimX && 6 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_8x6_Format;
} else if (8 == blockDimX && 8 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_8x8_Format;
} else if (10 == blockDimX && 5 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_10x5_Format;
} else if (10 == blockDimX && 6 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_10x6_Format;
} else if (10 == blockDimX && 8 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_10x8_Format;
} else if (10 == blockDimX && 10 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_10x10_Format;
} else if (12 == blockDimX && 10 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_12x10_Format;
} else if (12 == blockDimX && 12 == blockDimY) {
astcFormat = SkTextureCompressor::kASTC_12x12_Format;
} else {
// We don't support any other block dimensions..
return kFailure;
}
// Advance buf past the block dimensions
buf += 3;
// Read the width/height/depth from the buffer...
const int width = read_24bit(buf);
const int height = read_24bit(buf + 3);
const int depth = read_24bit(buf + 6);
if (1 != depth) {
// We don't support decoding 3D.
return kFailure;
}
// Advance the buffer past the image dimensions
buf += 9;
// Setup the sampler...
SkScaledBitmapSampler sampler(width, height, this->getSampleSize());
// Determine the alpha of the bitmap...
SkAlphaType alphaType = kOpaque_SkAlphaType;
if (this->getRequireUnpremultipliedColors()) {
alphaType = kUnpremul_SkAlphaType;
} else {
alphaType = kPremul_SkAlphaType;
}
// Set the config...
bm->setInfo(SkImageInfo::MakeN32(sampler.scaledWidth(), sampler.scaledHeight(), alphaType));
if (SkImageDecoder::kDecodeBounds_Mode == mode) {
return kSuccess;
}
if (!this->allocPixelRef(bm, nullptr)) {
return kFailure;
}
// Lock the pixels, since we're about to write to them...
SkAutoLockPixels alp(*bm);
if (!sampler.begin(bm, SkScaledBitmapSampler::kRGBA, *this)) {
return kFailure;
}
// ASTC Data is encoded as RGBA pixels, so we should extract it as such
int nPixels = width * height;
SkAutoMalloc outRGBAData(nPixels * 4);
uint8_t *outRGBADataPtr = reinterpret_cast<uint8_t *>(outRGBAData.get());
// Decode ASTC
if (!SkTextureCompressor::DecompressBufferFromFormat(
outRGBADataPtr, width*4, buf, width, height, astcFormat)) {
return kFailure;
}
// Set each of the pixels...
const int srcRowBytes = width * 4;
const int dstHeight = sampler.scaledHeight();
const uint8_t *srcRow = reinterpret_cast<uint8_t *>(outRGBADataPtr);
srcRow += sampler.srcY0() * srcRowBytes;
for (int y = 0; y < dstHeight; ++y) {
sampler.next(srcRow);
srcRow += sampler.srcDY() * srcRowBytes;
}
return kSuccess;
}
/////////////////////////////////////////////////////////////////////////////////////////
DEFINE_DECODER_CREATOR(ASTCImageDecoder);
/////////////////////////////////////////////////////////////////////////////////////////
static bool is_astc(SkStreamRewindable* stream) {
// Read the ASTC header and make sure it's valid.
uint32_t magic;
if (stream->read((void*)&magic, 4) != 4) {
return false;
}
return kASTCMagicNumber == SkEndian_SwapLE32(magic);
}
static SkImageDecoder* sk_libastc_dfactory(SkStreamRewindable* stream) {
if (is_astc(stream)) {
return new SkASTCImageDecoder;
}
return nullptr;
}
static SkImageDecoder_DecodeReg gReg(sk_libastc_dfactory);
static SkImageDecoder::Format get_format_astc(SkStreamRewindable* stream) {
if (is_astc(stream)) {
return SkImageDecoder::kASTC_Format;
}
return SkImageDecoder::kUnknown_Format;
}
static SkImageDecoder_FormatReg gFormatReg(get_format_astc);
|
