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