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 //! Weight the colour by alpha during cluster fit (disabled by default). 60 kWeightColourByAlpha = ( 1 << 7 ) 61 }; 62 63 // ----------------------------------------------------------------------------- 64 65 /*! @brief Compresses a 4x4 block of pixels. 66 67 @param rgba The rgba values of the 16 source pixels. 68 @param mask The valid pixel mask. 69 @param block Storage for the compressed DXT block. 70 @param flags Compression flags. 71 @param metric An optional perceptual metric. 72 73 The source pixels should be presented as a contiguous array of 16 rgba 74 values, with each component as 1 byte each. In memory this should be: 75 76 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 77 78 The mask parameter enables only certain pixels within the block. The lowest 79 bit enables the first pixel and so on up to the 16th bit. Bits beyond the 80 16th bit are ignored. Pixels that are not enabled are allowed to take 81 arbitrary colours in the output block. An example of how this can be used 82 is in the CompressImage function to disable pixels outside the bounds of 83 the image when the width or height is not divisible by 4. 84 85 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 86 however, DXT1 will be used by default if none is specified. When using DXT1 87 compression, 8 bytes of storage are required for the compressed DXT block. 88 DXT3 and DXT5 compression require 16 bytes of storage per block. 89 90 The flags parameter can also specify a preferred colour compressor to use 91 when fitting the RGB components of the data. Possible colour compressors 92 are: kColourClusterFit (the default), kColourRangeFit (very fast, low 93 quality) or kColourIterativeClusterFit (slowest, best quality). 94 95 When using kColourClusterFit or kColourIterativeClusterFit, an additional 96 flag can be specified to weight the importance of each pixel by its alpha 97 value. For images that are rendered using alpha blending, this can 98 significantly increase the perceived quality. 99 100 The metric parameter can be used to weight the relative importance of each 101 colour channel, or pass NULL to use the default uniform weight of 102 { 1.0f, 1.0f, 1.0f }. This replaces the previous flag-based control that 103 allowed either uniform or "perceptual" weights with the fixed values 104 { 0.2126f, 0.7152f, 0.0722f }. If non-NULL, the metric should point to a 105 contiguous array of 3 floats. 106 */ 107 void CompressMasked( u8 const* rgba, int mask, void* block, int flags, float* metric = 0 ); 108 109 // ----------------------------------------------------------------------------- 110 111 /*! @brief Compresses a 4x4 block of pixels. 112 113 @param rgba The rgba values of the 16 source pixels. 114 @param block Storage for the compressed DXT block. 115 @param flags Compression flags. 116 @param metric An optional perceptual metric. 117 118 The source pixels should be presented as a contiguous array of 16 rgba 119 values, with each component as 1 byte each. In memory this should be: 120 121 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 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 to use 129 when fitting the RGB components of the data. Possible colour compressors 130 are: kColourClusterFit (the default), kColourRangeFit (very fast, low 131 quality) or kColourIterativeClusterFit (slowest, best quality). 132 133 When using kColourClusterFit or kColourIterativeClusterFit, an additional 134 flag can be specified to weight the importance of each pixel by its alpha 135 value. For images that are rendered using alpha blending, this can 136 significantly increase the perceived quality. 137 138 The metric parameter can be used to weight the relative importance of each 139 colour channel, or pass NULL to use the default uniform weight of 140 { 1.0f, 1.0f, 1.0f }. This replaces the previous flag-based control that 141 allowed either uniform or "perceptual" weights with the fixed values 142 { 0.2126f, 0.7152f, 0.0722f }. If non-NULL, the metric should point to a 143 contiguous array of 3 floats. 144 145 This method is an inline that calls CompressMasked with a mask of 0xffff, 146 provided for compatibility with older versions of squish. 147 */ 148 inline void Compress( u8 const* rgba, void* block, int flags, float* metric = 0 ) 149 { 150 CompressMasked( rgba, 0xffff, block, flags, metric ); 151 } 152 153 // ----------------------------------------------------------------------------- 154 155 /*! @brief Decompresses a 4x4 block of pixels. 156 157 @param rgba Storage for the 16 decompressed pixels. 158 @param block The compressed DXT block. 159 @param flags Compression flags. 160 161 The decompressed pixels will be written as a contiguous array of 16 rgba 162 values, with each component as 1 byte each. In memory this is: 163 164 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 165 166 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 167 however, DXT1 will be used by default if none is specified. All other flags 168 are ignored. 169 */ 170 void Decompress( u8* rgba, void const* block, int flags ); 171 172 // ----------------------------------------------------------------------------- 173 174 /*! @brief Computes the amount of compressed storage required. 175 176 @param width The width of the image. 177 @param height The height of the image. 178 @param flags Compression flags. 179 180 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 181 however, DXT1 will be used by default if none is specified. All other flags 182 are ignored. 183 184 Most DXT images will be a multiple of 4 in each dimension, but this 185 function supports arbitrary size images by allowing the outer blocks to 186 be only partially used. 187 */ 188 int GetStorageRequirements( int width, int height, int flags ); 189 190 // ----------------------------------------------------------------------------- 191 192 /*! @brief Compresses an image in memory. 193 194 @param rgba The pixels of the source. 195 @param width The width of the source image. 196 @param height The height of the source image. 197 @param blocks Storage for the compressed output. 198 @param flags Compression flags. 199 @param metric An optional perceptual metric. 200 201 The source pixels should be presented as a contiguous array of width*height 202 rgba values, with each component as 1 byte each. In memory this should be: 203 204 { r1, g1, b1, a1, .... , rn, gn, bn, an } for n = width*height 205 206 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 207 however, DXT1 will be used by default if none is specified. When using DXT1 208 compression, 8 bytes of storage are required for each compressed DXT block. 209 DXT3 and DXT5 compression require 16 bytes of storage per block. 210 211 The flags parameter can also specify a preferred colour compressor to use 212 when fitting the RGB components of the data. Possible colour compressors 213 are: kColourClusterFit (the default), kColourRangeFit (very fast, low 214 quality) or kColourIterativeClusterFit (slowest, best quality). 215 216 When using kColourClusterFit or kColourIterativeClusterFit, an additional 217 flag can be specified to weight the importance of each pixel by its alpha 218 value. For images that are rendered using alpha blending, this can 219 significantly increase the perceived quality. 220 221 The metric parameter can be used to weight the relative importance of each 222 colour channel, or pass NULL to use the default uniform weight of 223 { 1.0f, 1.0f, 1.0f }. This replaces the previous flag-based control that 224 allowed either uniform or "perceptual" weights with the fixed values 225 { 0.2126f, 0.7152f, 0.0722f }. If non-NULL, the metric should point to a 226 contiguous array of 3 floats. 227 228 Internally this function calls squish::CompressMasked for each block, which 229 allows for pixels outside the image to take arbitrary values. The function 230 squish::GetStorageRequirements can be called to compute the amount of memory 231 to allocate for the compressed output. 232 */ 233 void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags, float* metric = 0 ); 234 235 // ----------------------------------------------------------------------------- 236 237 /*! @brief Decompresses an image in memory. 238 239 @param rgba Storage for the decompressed pixels. 240 @param width The width of the source image. 241 @param height The height of the source image. 242 @param blocks The compressed DXT blocks. 243 @param flags Compression flags. 244 245 The decompressed pixels will be written as a contiguous array of width*height 246 16 rgba values, with each component as 1 byte each. In memory this is: 247 248 { r1, g1, b1, a1, .... , rn, gn, bn, an } for n = width*height 249 250 The flags parameter should specify either kDxt1, kDxt3 or kDxt5 compression, 251 however, DXT1 will be used by default if none is specified. All other flags 252 are ignored. 253 254 Internally this function calls squish::Decompress for each block. 255 */ 256 void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags ); 257 258 // ----------------------------------------------------------------------------- 259 260 } // namespace squish 261 262 #endif // ndef SQUISH_H 263 264