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 #ifndef SQUISH_H 27 #define SQUISH_H 28 29 //! All squish API functions live in this namespace. 30 namespace squish { 31 32 // ----------------------------------------------------------------------------- 33 34 //! Typedef a quantity that is a single unsigned byte. 35 typedef unsigned char u8; 36 37 // ----------------------------------------------------------------------------- 38 39 enum 40 { 41 //! Use DXT1 compression. 42 kDxt1 = ( 1 << 0 ), 43 44 //! Use DXT3 compression. 45 kDxt3 = ( 1 << 1 ), 46 47 //! Use DXT5 compression. 48 kDxt5 = ( 1 << 2 ), 49 50 //! Use a very slow but very high quality colour compressor. 51 kColourIterativeClusterFit = ( 1 << 8 ), 52 53 //! Use a slow but high quality colour compressor (the default). 54 kColourClusterFit = ( 1 << 3 ), 55 56 //! Use a fast but low quality colour compressor. 57 kColourRangeFit = ( 1 << 4 ), 58 59 //! Use a perceptual metric for colour error (the default). 60 kColourMetricPerceptual = ( 1 << 5 ), 61 62 //! Use a uniform metric for colour error. 63 kColourMetricUniform = ( 1 << 6 ), 64 65 //! Weight the colour by alpha during cluster fit (disabled by default). 66 kWeightColourByAlpha = ( 1 << 7 ) 67 }; 68 69 // ----------------------------------------------------------------------------- 70 71 /*! @brief Compresses a 4x4 block of pixels. 72 73 @param rgba The rgba values of the 16 source pixels. 74 @param block Storage for the compressed DXT block. 75 @param flags Compression flags. 76 77 The source pixels should be presented as a contiguous array of 16 rgba 78 values, with each component as 1 byte each. In memory this should be: 79 80 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 81 82 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 83 however, DXT1 will be used by default if none is specified. When using DXT1 84 compression, 8 bytes of storage are required for the compressed DXT block. 85 DXT3 and DXT5 compression require 16 bytes of storage per block. 86 87 The flags parameter can also specify a preferred colour compressor and 88 colour error metric to use when fitting the RGB components of the data. 89 Possible colour compressors are: kColourClusterFit (the default), 90 kColourRangeFit or kColourIterativeClusterFit. Possible colour error metrics 91 are: kColourMetricPerceptual (the default) or kColourMetricUniform. If no 92 flags are specified in any particular category then the default will be 93 used. Unknown flags are ignored. 94 95 When using kColourClusterFit, an additional flag can be specified to 96 weight the colour of each pixel by its alpha value. For images that are 97 rendered using alpha blending, this can significantly increase the 98 perceived quality. 99 */ 100 void Compress( u8 const* rgba, void* block, int flags ); 101 102 // ----------------------------------------------------------------------------- 103 104 /*! @brief Compresses a 4x4 block of pixels. 105 106 @param rgba The rgba values of the 16 source pixels. 107 @param mask The valid pixel mask. 108 @param block Storage for the compressed DXT block. 109 @param flags Compression flags. 110 111 The source pixels should be presented as a contiguous array of 16 rgba 112 values, with each component as 1 byte each. In memory this should be: 113 114 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 115 116 The mask parameter enables only certain pixels within the block. The lowest 117 bit enables the first pixel and so on up to the 16th bit. Bits beyond the 118 16th bit are ignored. Pixels that are not enabled are allowed to take 119 arbitrary colours in the output block. An example of how this can be used 120 is in the CompressImage function to disable pixels outside the bounds of 121 the image when the width or height is not divisible by 4. 122 123 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 124 however, DXT1 will be used by default if none is specified. When using DXT1 125 compression, 8 bytes of storage are required for the compressed DXT block. 126 DXT3 and DXT5 compression require 16 bytes of storage per block. 127 128 The flags parameter can also specify a preferred colour compressor and 129 colour error metric to use when fitting the RGB components of the data. 130 Possible colour compressors are: kColourClusterFit (the default), 131 kColourRangeFit or kColourIterativeClusterFit. Possible colour error metrics 132 are: kColourMetricPerceptual (the default) or kColourMetricUniform. If no 133 flags are specified in any particular category then the default will be 134 used. Unknown flags are ignored. 135 136 When using kColourClusterFit, an additional flag can be specified to 137 weight the colour of each pixel by its alpha value. For images that are 138 rendered using alpha blending, this can significantly increase the 139 perceived quality. 140 */ 141 void CompressMasked( u8 const* rgba, int mask, void* block, int flags ); 142 143 // ----------------------------------------------------------------------------- 144 145 /*! @brief Decompresses a 4x4 block of pixels. 146 147 @param rgba Storage for the 16 decompressed pixels. 148 @param block The compressed DXT block. 149 @param flags Compression flags. 150 151 The decompressed pixels will be written as a contiguous array of 16 rgba 152 values, with each component as 1 byte each. In memory this is: 153 154 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 155 156 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 157 however, DXT1 will be used by default if none is specified. All other flags 158 are ignored. 159 */ 160 void Decompress( u8* rgba, void const* block, int flags ); 161 162 // ----------------------------------------------------------------------------- 163 164 /*! @brief Computes the amount of compressed storage required. 165 166 @param width The width of the image. 167 @param height The height of the image. 168 @param flags Compression flags. 169 170 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 171 however, DXT1 will be used by default if none is specified. All other flags 172 are ignored. 173 174 Most DXT images will be a multiple of 4 in each dimension, but this 175 function supports arbitrary size images by allowing the outer blocks to 176 be only partially used. 177 */ 178 int GetStorageRequirements( int width, int height, int flags ); 179 180 // ----------------------------------------------------------------------------- 181 182 /*! @brief Compresses an image in memory. 183 184 @param rgba The pixels of the source. 185 @param width The width of the source image. 186 @param height The height of the source image. 187 @param blocks Storage for the compressed output. 188 @param flags Compression flags. 189 190 The source pixels should be presented as a contiguous array of width*height 191 rgba values, with each component as 1 byte each. In memory this should be: 192 193 { r1, g1, b1, a1, .... , rn, gn, bn, an } for n = width*height 194 195 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 196 however, DXT1 will be used by default if none is specified. When using DXT1 197 compression, 8 bytes of storage are required for each compressed DXT block. 198 DXT3 and DXT5 compression require 16 bytes of storage per block. 199 200 The flags parameter can also specify a preferred colour compressor and 201 colour error metric to use when fitting the RGB components of the data. 202 Possible colour compressors are: kColourClusterFit (the default), 203 kColourRangeFit or kColourIterativeClusterFit. Possible colour error metrics 204 are: kColourMetricPerceptual (the default) or kColourMetricUniform. If no 205 flags are specified in any particular category then the default will be 206 used. Unknown flags are ignored. 207 208 When using kColourClusterFit, an additional flag can be specified to 209 weight the colour of each pixel by its alpha value. For images that are 210 rendered using alpha blending, this can significantly increase the 211 perceived quality. 212 213 Internally this function calls squish::Compress for each block. To see how 214 much memory is required in the compressed image, use 215 squish::GetStorageRequirements. 216 */ 217 void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags ); 218 219 // ----------------------------------------------------------------------------- 220 221 /*! @brief Decompresses an image in memory. 222 223 @param rgba Storage for the decompressed pixels. 224 @param width The width of the source image. 225 @param height The height of the source image. 226 @param blocks The compressed DXT blocks. 227 @param flags Compression flags. 228 229 The decompressed pixels will be written as a contiguous array of width*height 230 16 rgba values, with each component as 1 byte each. In memory this is: 231 232 { r1, g1, b1, a1, .... , rn, gn, bn, an } for n = width*height 233 234 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 235 however, DXT1 will be used by default if none is specified. All other flags 236 are ignored. 237 238 Internally this function calls squish::Decompress for each block. 239 */ 240 void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags ); 241 242 // ----------------------------------------------------------------------------- 243 244 } // namespace squish 245 246 #endif // ndef SQUISH_H 247 248