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
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
/* -----------------------------------------------------------------------------
Copyright (c) 2006 Simon Brown si@sjbrown.co.uk
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-------------------------------------------------------------------------- */
#ifndef SQUISH_H
#define SQUISH_H
//! All squish API functions live in this namespace.
namespace squish {
// -----------------------------------------------------------------------------
//! Typedef a quantity that is a single unsigned byte.
typedef unsigned char u8;
// -----------------------------------------------------------------------------
enum
{
//! Use DXT1 compression.
kDxt1 = ( 1 << 0 ),
//! Use DXT3 compression.
kDxt3 = ( 1 << 1 ),
//! Use DXT5 compression.
kDxt5 = ( 1 << 2 ),
//! Use a very slow but very high quality colour compressor.
kColourIterativeClusterFit = ( 1 << 8 ),
//! Use a slow but high quality colour compressor (the default).
kColourClusterFit = ( 1 << 3 ),
//! Use a fast but low quality colour compressor.
kColourRangeFit = ( 1 << 4 ),
//! Use a perceptual metric for colour error (the default).
kColourMetricPerceptual = ( 1 << 5 ),
//! Use a uniform metric for colour error.
kColourMetricUniform = ( 1 << 6 ),
//! Weight the colour by alpha during cluster fit (disabled by default).
kWeightColourByAlpha = ( 1 << 7 )
};
// -----------------------------------------------------------------------------
/*! @brief Compresses a 4x4 block of pixels.
@param rgba The rgba values of the 16 source pixels.
@param block Storage for the compressed DXT block.
@param flags Compression flags.
The source pixels should be presented as a contiguous array of 16 rgba
values, with each component as 1 byte each. In memory this should be:
{ r1, g1, b1, a1, .... , r16, g16, b16, a16 }
The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression,
however, DXT1 will be used by default if none is specified. When using DXT1
compression, 8 bytes of storage are required for the compressed DXT block.
DXT3 and DXT5 compression require 16 bytes of storage per block.
The flags parameter can also specify a preferred colour compressor and
colour error metric to use when fitting the RGB components of the data.
Possible colour compressors are: kColourClusterFit (the default),
kColourRangeFit or kColourIterativeClusterFit. Possible colour error metrics
are: kColourMetricPerceptual (the default) or kColourMetricUniform. If no
flags are specified in any particular category then the default will be
used. Unknown flags are ignored.
When using kColourClusterFit, an additional flag can be specified to
weight the colour of each pixel by its alpha value. For images that are
rendered using alpha blending, this can significantly increase the
perceived quality.
*/
void Compress( u8 const* rgba, void* block, int flags );
// -----------------------------------------------------------------------------
/*! @brief Compresses a 4x4 block of pixels.
@param rgba The rgba values of the 16 source pixels.
@param mask The valid pixel mask.
@param block Storage for the compressed DXT block.
@param flags Compression flags.
The source pixels should be presented as a contiguous array of 16 rgba
values, with each component as 1 byte each. In memory this should be:
{ r1, g1, b1, a1, .... , r16, g16, b16, a16 }
The mask parameter enables only certain pixels within the block. The lowest
bit enables the first pixel and so on up to the 16th bit. Bits beyond the
16th bit are ignored. Pixels that are not enabled are allowed to take
arbitrary colours in the output block. An example of how this can be used
is in the CompressImage function to disable pixels outside the bounds of
the image when the width or height is not divisible by 4.
The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression,
however, DXT1 will be used by default if none is specified. When using DXT1
compression, 8 bytes of storage are required for the compressed DXT block.
DXT3 and DXT5 compression require 16 bytes of storage per block.
The flags parameter can also specify a preferred colour compressor and
colour error metric to use when fitting the RGB components of the data.
Possible colour compressors are: kColourClusterFit (the default),
kColourRangeFit or kColourIterativeClusterFit. Possible colour error metrics
are: kColourMetricPerceptual (the default) or kColourMetricUniform. If no
flags are specified in any particular category then the default will be
used. Unknown flags are ignored.
When using kColourClusterFit, an additional flag can be specified to
weight the colour of each pixel by its alpha value. For images that are
rendered using alpha blending, this can significantly increase the
perceived quality.
*/
void CompressMasked( u8 const* rgba, int mask, void* block, int flags );
// -----------------------------------------------------------------------------
/*! @brief Decompresses a 4x4 block of pixels.
@param rgba Storage for the 16 decompressed pixels.
@param block The compressed DXT block.
@param flags Compression flags.
The decompressed pixels will be written as a contiguous array of 16 rgba
values, with each component as 1 byte each. In memory this is:
{ r1, g1, b1, a1, .... , r16, g16, b16, a16 }
The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression,
however, DXT1 will be used by default if none is specified. All other flags
are ignored.
*/
void Decompress( u8* rgba, void const* block, int flags );
// -----------------------------------------------------------------------------
/*! @brief Computes the amount of compressed storage required.
@param width The width of the image.
@param height The height of the image.
@param flags Compression flags.
The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression,
however, DXT1 will be used by default if none is specified. All other flags
are ignored.
Most DXT images will be a multiple of 4 in each dimension, but this
function supports arbitrary size images by allowing the outer blocks to
be only partially used.
*/
int GetStorageRequirements( int width, int height, int flags );
// -----------------------------------------------------------------------------
/*! @brief Compresses an image in memory.
@param rgba The pixels of the source.
@param width The width of the source image.
@param height The height of the source image.
@param blocks Storage for the compressed output.
@param flags Compression flags.
The source pixels should be presented as a contiguous array of width*height
rgba values, with each component as 1 byte each. In memory this should be:
{ r1, g1, b1, a1, .... , rn, gn, bn, an } for n = width*height
The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression,
however, DXT1 will be used by default if none is specified. When using DXT1
compression, 8 bytes of storage are required for each compressed DXT block.
DXT3 and DXT5 compression require 16 bytes of storage per block.
The flags parameter can also specify a preferred colour compressor and
colour error metric to use when fitting the RGB components of the data.
Possible colour compressors are: kColourClusterFit (the default),
kColourRangeFit or kColourIterativeClusterFit. Possible colour error metrics
are: kColourMetricPerceptual (the default) or kColourMetricUniform. If no
flags are specified in any particular category then the default will be
used. Unknown flags are ignored.
When using kColourClusterFit, an additional flag can be specified to
weight the colour of each pixel by its alpha value. For images that are
rendered using alpha blending, this can significantly increase the
perceived quality.
Internally this function calls squish::Compress for each block. To see how
much memory is required in the compressed image, use
squish::GetStorageRequirements.
*/
void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags );
// -----------------------------------------------------------------------------
/*! @brief Decompresses an image in memory.
@param rgba Storage for the decompressed pixels.
@param width The width of the source image.
@param height The height of the source image.
@param blocks The compressed DXT blocks.
@param flags Compression flags.
The decompressed pixels will be written as a contiguous array of width*height
16 rgba values, with each component as 1 byte each. In memory this is:
{ r1, g1, b1, a1, .... , rn, gn, bn, an } for n = width*height
The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression,
however, DXT1 will be used by default if none is specified. All other flags
are ignored.
Internally this function calls squish::Decompress for each block.
*/
void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags );
// -----------------------------------------------------------------------------
} // namespace squish
#endif // ndef SQUISH_H
|