1 /* -----------------------------------------------------------------------------
2
3 Copyright (c) 2006 Simon Brown si@sjbrown.co.uk
4
5 Permission is hereby granted, free of charge, to any person obtaining
6 a copy of this software and associated documentation files (the
7 "Software"), to deal in the Software without restriction, including
8 without limitation the rights to use, copy, modify, merge, publish,
9 distribute, sublicense, and/or sell copies of the Software, and to
10 permit persons to whom the Software is furnished to do so, subject to
11 the following conditions:
12
13 The above copyright notice and this permission notice shall be included
14 in all copies or substantial portions of the Software.
15
16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
19 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
20 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
21 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
22 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23
24 -------------------------------------------------------------------------- */
25
26 #include "squish.h"
27 #include "colourset.h"
28 #include "maths.h"
29 #include "rangefit.h"
30 #include "clusterfit.h"
31 #include "colourblock.h"
32 #include "alpha.h"
33 #include "singlecolourfit.h"
34
35 namespace squish {
36
FixFlags(int flags)37 static int FixFlags( int flags )
38 {
39 // grab the flag bits
40 int method = flags & ( kDxt1 | kDxt3 | kDxt5 | kBc4 | kBc5 );
41 int fit = flags & ( kColourIterativeClusterFit | kColourClusterFit | kColourRangeFit );
42 int extra = flags & kWeightColourByAlpha;
43
44 // set defaults
45 if ( method != kDxt3
46 && method != kDxt5
47 && method != kBc4
48 && method != kBc5 )
49 {
50 method = kDxt1;
51 }
52 if( fit != kColourRangeFit && fit != kColourIterativeClusterFit )
53 fit = kColourClusterFit;
54
55 // done
56 return method | fit | extra;
57 }
58
CompressMasked(u8 const * rgba,int mask,void * block,int flags,float * metric)59 void CompressMasked( u8 const* rgba, int mask, void* block, int flags, float* metric )
60 {
61 // fix any bad flags
62 flags = FixFlags( flags );
63
64 if ( ( flags & ( kBc4 | kBc5 ) ) != 0 )
65 {
66 u8 alpha[16*4];
67 for( int i = 0; i < 16; ++i )
68 {
69 alpha[i*4 + 3] = rgba[i*4 + 0]; // copy R to A
70 }
71
72 u8* rBlock = reinterpret_cast< u8* >( block );
73 CompressAlphaDxt5( alpha, mask, rBlock );
74
75 if ( ( flags & ( kBc5 ) ) != 0 )
76 {
77 for( int i = 0; i < 16; ++i )
78 {
79 alpha[i*4 + 3] = rgba[i*4 + 1]; // copy G to A
80 }
81
82 u8* gBlock = reinterpret_cast< u8* >( block ) + 8;
83 CompressAlphaDxt5( alpha, mask, gBlock );
84 }
85
86 return;
87 }
88
89 // get the block locations
90 void* colourBlock = block;
91 void* alphaBlock = block;
92 if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
93 colourBlock = reinterpret_cast< u8* >( block ) + 8;
94
95 // create the minimal point set
96 ColourSet colours( rgba, mask, flags );
97
98 // check the compression type and compress colour
99 if( colours.GetCount() == 1 )
100 {
101 // always do a single colour fit
102 SingleColourFit fit( &colours, flags );
103 fit.Compress( colourBlock );
104 }
105 else if( ( flags & kColourRangeFit ) != 0 || colours.GetCount() == 0 )
106 {
107 // do a range fit
108 RangeFit fit( &colours, flags, metric );
109 fit.Compress( colourBlock );
110 }
111 else
112 {
113 // default to a cluster fit (could be iterative or not)
114 ClusterFit fit( &colours, flags, metric );
115 fit.Compress( colourBlock );
116 }
117
118 // compress alpha separately if necessary
119 if( ( flags & kDxt3 ) != 0 )
120 CompressAlphaDxt3( rgba, mask, alphaBlock );
121 else if( ( flags & kDxt5 ) != 0 )
122 CompressAlphaDxt5( rgba, mask, alphaBlock );
123 }
124
Decompress(u8 * rgba,void const * block,int flags)125 void Decompress( u8* rgba, void const* block, int flags )
126 {
127 // fix any bad flags
128 flags = FixFlags( flags );
129
130 // get the block locations
131 void const* colourBlock = block;
132 void const* alphaBock = block;
133 if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
134 colourBlock = reinterpret_cast< u8 const* >( block ) + 8;
135
136 // decompress colour
137 DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );
138
139 // decompress alpha separately if necessary
140 if( ( flags & kDxt3 ) != 0 )
141 DecompressAlphaDxt3( rgba, alphaBock );
142 else if( ( flags & kDxt5 ) != 0 )
143 DecompressAlphaDxt5( rgba, alphaBock );
144 }
145
GetStorageRequirements(int width,int height,int flags)146 int GetStorageRequirements( int width, int height, int flags )
147 {
148 // fix any bad flags
149 flags = FixFlags( flags );
150
151 // compute the storage requirements
152 int blockcount = ( ( width + 3 )/4 ) * ( ( height + 3 )/4 );
153 int blocksize = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
154 return blockcount*blocksize;
155 }
156
CompressImage(u8 const * rgba,int width,int height,void * blocks,int flags,float * metric)157 void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags, float* metric )
158 {
159 // fix any bad flags
160 flags = FixFlags( flags );
161
162 // initialise the block output
163 u8* targetBlock = reinterpret_cast< u8* >( blocks );
164 int bytesPerBlock = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
165
166 // loop over blocks
167 for( int y = 0; y < height; y += 4 )
168 {
169 for( int x = 0; x < width; x += 4 )
170 {
171 // build the 4x4 block of pixels
172 u8 sourceRgba[16*4];
173 u8* targetPixel = sourceRgba;
174 int mask = 0;
175 for( int py = 0; py < 4; ++py )
176 {
177 for( int px = 0; px < 4; ++px )
178 {
179 // get the source pixel in the image
180 int sx = x + px;
181 int sy = y + py;
182
183 // enable if we're in the image
184 if( sx < width && sy < height )
185 {
186 // copy the rgba value
187 u8 const* sourcePixel = rgba + 4*( width*sy + sx );
188 for( int i = 0; i < 4; ++i )
189 *targetPixel++ = *sourcePixel++;
190
191 // enable this pixel
192 mask |= ( 1 << ( 4*py + px ) );
193 }
194 else
195 {
196 // skip this pixel as its outside the image
197 targetPixel += 4;
198 }
199 }
200 }
201
202 // compress it into the output
203 CompressMasked( sourceRgba, mask, targetBlock, flags, metric );
204
205 // advance
206 targetBlock += bytesPerBlock;
207 }
208 }
209 }
210
DecompressImage(u8 * rgba,int width,int height,void const * blocks,int flags)211 void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags )
212 {
213 // fix any bad flags
214 flags = FixFlags( flags );
215
216 // initialise the block input
217 u8 const* sourceBlock = reinterpret_cast< u8 const* >( blocks );
218 int bytesPerBlock = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
219
220 // loop over blocks
221 for( int y = 0; y < height; y += 4 )
222 {
223 for( int x = 0; x < width; x += 4 )
224 {
225 // decompress the block
226 u8 targetRgba[4*16];
227 Decompress( targetRgba, sourceBlock, flags );
228
229 // write the decompressed pixels to the correct image locations
230 u8 const* sourcePixel = targetRgba;
231 for( int py = 0; py < 4; ++py )
232 {
233 for( int px = 0; px < 4; ++px )
234 {
235 // get the target location
236 int sx = x + px;
237 int sy = y + py;
238 if( sx < width && sy < height )
239 {
240 u8* targetPixel = rgba + 4*( width*sy + sx );
241
242 // copy the rgba value
243 for( int i = 0; i < 4; ++i )
244 *targetPixel++ = *sourcePixel++;
245 }
246 else
247 {
248 // skip this pixel as its outside the image
249 sourcePixel += 4;
250 }
251 }
252 }
253
254 // advance
255 sourceBlock += bytesPerBlock;
256 }
257 }
258 }
259
260 } // namespace squish
261