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 BC4 compression. 51 kBc4 = ( 1 << 3 ), 52 53 //! Use BC5 compression. 54 kBc5 = ( 1 << 4 ), 55 56 //! Use a slow but high quality colour compressor (the default). 57 kColourClusterFit = ( 1 << 5 ), 58 59 //! Use a fast but low quality colour compressor. 60 kColourRangeFit = ( 1 << 6 ), 61 62 //! Weight the colour by alpha during cluster fit (disabled by default). 63 kWeightColourByAlpha = ( 1 << 7 ), 64 65 //! Use a very slow but very high quality colour compressor. 66 kColourIterativeClusterFit = ( 1 << 8 ), 67 68 //! Source is BGRA rather than RGBA 69 kSourceBGRA = ( 1 << 9 ) 70 }; 71 72 // ----------------------------------------------------------------------------- 73 74 /*! @brief Compresses a 4x4 block of pixels. 75 76 @param rgba The rgba values of the 16 source pixels. 77 @param mask The valid pixel mask. 78 @param block Storage for the compressed DXT block. 79 @param flags Compression flags. 80 @param metric An optional perceptual metric. 81 82 The source pixels should be presented as a contiguous array of 16 rgba 83 values, with each component as 1 byte each. In memory this should be: 84 85 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 86 87 The mask parameter enables only certain pixels within the block. The lowest 88 bit enables the first pixel and so on up to the 16th bit. Bits beyond the 89 16th bit are ignored. Pixels that are not enabled are allowed to take 90 arbitrary colours in the output block. An example of how this can be used 91 is in the CompressImage function to disable pixels outside the bounds of 92 the image when the width or height is not divisible by 4. 93 94 The flags parameter should specify kDxt1, kDxt3, kDxt5, kBc4, or kBc5 compression, 95 however, DXT1 will be used by default if none is specified. When using DXT1 96 compression, 8 bytes of storage are required for the compressed DXT block. 97 DXT3 and DXT5 compression require 16 bytes of storage per block. 98 99 The flags parameter can also specify a preferred colour compressor to use 100 when fitting the RGB components of the data. Possible colour compressors 101 are: kColourClusterFit (the default), kColourRangeFit (very fast, low 102 quality) or kColourIterativeClusterFit (slowest, best quality). 103 104 When using kColourClusterFit or kColourIterativeClusterFit, an additional 105 flag can be specified to weight the importance of each pixel by its alpha 106 value. For images that are rendered using alpha blending, this can 107 significantly increase the perceived quality. 108 109 The metric parameter can be used to weight the relative importance of each 110 colour channel, or pass NULL to use the default uniform weight of 111 { 1.0f, 1.0f, 1.0f }. This replaces the previous flag-based control that 112 allowed either uniform or "perceptual" weights with the fixed values 113 { 0.2126f, 0.7152f, 0.0722f }. If non-NULL, the metric should point to a 114 contiguous array of 3 floats. 115 */ 116 void CompressMasked( u8 const* rgba, int mask, void* block, int flags, float* metric = 0 ); 117 118 // ----------------------------------------------------------------------------- 119 120 /*! @brief Compresses a 4x4 block of pixels. 121 122 @param rgba The rgba values of the 16 source pixels. 123 @param block Storage for the compressed DXT block. 124 @param flags Compression flags. 125 @param metric An optional perceptual metric. 126 127 The source pixels should be presented as a contiguous array of 16 rgba 128 values, with each component as 1 byte each. In memory this should be: 129 130 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 131 132 The flags parameter should specify kDxt1, kDxt3, kDxt5, kBc4, or kBc5 compression, 133 however, DXT1 will be used by default if none is specified. When using DXT1 134 compression, 8 bytes of storage are required for the compressed DXT block. 135 DXT3 and DXT5 compression require 16 bytes of storage per block. 136 137 The flags parameter can also specify a preferred colour compressor to use 138 when fitting the RGB components of the data. Possible colour compressors 139 are: kColourClusterFit (the default), kColourRangeFit (very fast, low 140 quality) or kColourIterativeClusterFit (slowest, best quality). 141 142 When using kColourClusterFit or kColourIterativeClusterFit, an additional 143 flag can be specified to weight the importance of each pixel by its alpha 144 value. For images that are rendered using alpha blending, this can 145 significantly increase the perceived quality. 146 147 The metric parameter can be used to weight the relative importance of each 148 colour channel, or pass NULL to use the default uniform weight of 149 { 1.0f, 1.0f, 1.0f }. This replaces the previous flag-based control that 150 allowed either uniform or "perceptual" weights with the fixed values 151 { 0.2126f, 0.7152f, 0.0722f }. If non-NULL, the metric should point to a 152 contiguous array of 3 floats. 153 154 This method is an inline that calls CompressMasked with a mask of 0xffff, 155 provided for compatibility with older versions of squish. 156 */ 157 inline void Compress( u8 const* rgba, void* block, int flags, float* metric = 0 ) 158 { 159 CompressMasked( rgba, 0xffff, block, flags, metric ); 160 } 161 162 // ----------------------------------------------------------------------------- 163 164 /*! @brief Decompresses a 4x4 block of pixels. 165 166 @param rgba Storage for the 16 decompressed pixels. 167 @param block The compressed DXT block. 168 @param flags Compression flags. 169 170 The decompressed pixels will be written as a contiguous array of 16 rgba 171 values, with each component as 1 byte each. In memory this is: 172 173 { r1, g1, b1, a1, .... , r16, g16, b16, a16 } 174 175 The flags parameter should specify kDxt1, kDxt3, kDxt5, kBc4, or kBc5 compression, 176 however, DXT1 will be used by default if none is specified. All other flags 177 are ignored. 178 */ 179 void Decompress( u8* rgba, void const* block, int flags ); 180 181 // ----------------------------------------------------------------------------- 182 183 /*! @brief Computes the amount of compressed storage required. 184 185 @param width The width of the image. 186 @param height The height of the image. 187 @param flags Compression flags. 188 189 The flags parameter should specify kDxt1, kDxt3, kDxt5, kBc4, or kBc5 compression, 190 however, DXT1 will be used by default if none is specified. All other flags 191 are ignored. 192 193 Most DXT images will be a multiple of 4 in each dimension, but this 194 function supports arbitrary size images by allowing the outer blocks to 195 be only partially used. 196 */ 197 int GetStorageRequirements( int width, int height, int flags ); 198 199 // ----------------------------------------------------------------------------- 200 201 /*! @brief Compresses an image in memory. 202 203 @param rgba The pixels of the source. 204 @param width The width of the source image. 205 @param height The height of the source image. 206 @param pitch The pitch of the source image. 207 @param blocks Storage for the compressed output. 208 @param flags Compression flags. 209 @param metric An optional perceptual metric. 210 211 The source pixels should be presented as a contiguous array of width*height 212 rgba values, with each component as 1 byte each. In memory this should be: 213 214 { r1, g1, b1, a1, .... , rn, gn, bn, an } for n = width*height 215 216 The flags parameter should specify kDxt1, kDxt3, kDxt5, kBc4, or kBc5 compression, 217 however, DXT1 will be used by default if none is specified. When using DXT1 218 compression, 8 bytes of storage are required for each compressed DXT block. 219 DXT3 and DXT5 compression require 16 bytes of storage per block. 220 221 The flags parameter can also specify a preferred colour compressor to use 222 when fitting the RGB components of the data. Possible colour compressors 223 are: kColourClusterFit (the default), kColourRangeFit (very fast, low 224 quality) or kColourIterativeClusterFit (slowest, best quality). 225 226 When using kColourClusterFit or kColourIterativeClusterFit, an additional 227 flag can be specified to weight the importance of each pixel by its alpha 228 value. For images that are rendered using alpha blending, this can 229 significantly increase the perceived quality. 230 231 The metric parameter can be used to weight the relative importance of each 232 colour channel, or pass NULL to use the default uniform weight of 233 { 1.0f, 1.0f, 1.0f }. This replaces the previous flag-based control that 234 allowed either uniform or "perceptual" weights with the fixed values 235 { 0.2126f, 0.7152f, 0.0722f }. If non-NULL, the metric should point to a 236 contiguous array of 3 floats. 237 238 Internally this function calls squish::CompressMasked for each block, which 239 allows for pixels outside the image to take arbitrary values. The function 240 squish::GetStorageRequirements can be called to compute the amount of memory 241 to allocate for the compressed output. 242 243 Note on compression quality: When compressing textures with 244 libsquish it is recommended to apply a gamma-correction 245 beforehand. This will reduce the blockiness in dark areas. The 246 level of necessary gamma-correction is platform dependent. For 247 example, a gamma correction with gamma = 0.5 before compression 248 and gamma = 2.0 after decompression yields good results on the 249 Windows platform but for other platforms like MacOS X a different 250 gamma value may be more suitable. 251 */ 252 void CompressImage( u8 const* rgba, int width, int height, int pitch, void* blocks, int flags, float* metric = 0 ); 253 void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags, float* metric = 0 ); 254 255 // ----------------------------------------------------------------------------- 256 257 /*! @brief Decompresses an image in memory. 258 259 @param rgba Storage for the decompressed pixels. 260 @param width The width of the source image. 261 @param height The height of the source image. 262 @param pitch The pitch of the decompressed pixels. 263 @param blocks The compressed DXT blocks. 264 @param flags Compression flags. 265 266 The decompressed pixels will be written as a contiguous array of width*height 267 16 rgba values, with each component as 1 byte each. In memory this is: 268 269 { r1, g1, b1, a1, .... , rn, gn, bn, an } for n = width*height 270 271 The flags parameter should specify kDxt1, kDxt3, kDxt5, kBc4, or kBc5 compression, 272 however, DXT1 will be used by default if none is specified. All other flags 273 are ignored. 274 275 Internally this function calls squish::Decompress for each block. 276 */ 277 void DecompressImage( u8* rgba, int width, int height, int pitch, void const* blocks, int flags ); 278 void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags ); 279 280 // ----------------------------------------------------------------------------- 281 282 /*! @brief Computes MSE of an compressed image in memory. 283 284 @param rgba The original image pixels. 285 @param width The width of the source image. 286 @param height The height of the source image. 287 @param pitch The pitch of the source image. 288 @param dxt The compressed dxt blocks 289 @param flags Compression flags. 290 @param colourMSE The MSE of the colour values. 291 @param alphaMSE The MSE of the alpha values. 292 293 The colour MSE and alpha MSE are computed across all pixels. The colour MSE is 294 averaged across all rgb values (i.e. colourMSE = sum sum_k ||dxt.k - rgba.k||/3) 295 296 The flags parameter should specify kDxt1, kDxt3, kDxt5, kBc4, or kBc5 compression, 297 however, DXT1 will be used by default if none is specified. All other flags 298 are ignored. 299 300 Internally this function calls squish::Decompress for each block. 301 */ 302 void ComputeMSE(u8 const *rgba, int width, int height, int pitch, u8 const *dxt, int flags, double &colourMSE, double &alphaMSE); 303 void ComputeMSE(u8 const *rgba, int width, int height, u8 const *dxt, int flags, double &colourMSE, double &alphaMSE); 304 305 // ----------------------------------------------------------------------------- 306 307 } // namespace squish 308 309 #endif // ndef SQUISH_H 310