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404 lines
13 KiB
C++
404 lines
13 KiB
C++
/* -----------------------------------------------------------------------------
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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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#include <string.h>
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#include "squish.h"
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#include "colourset.h"
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#include "maths.h"
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#include "rangefit.h"
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#include "clusterfit.h"
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#include "colourblock.h"
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#include "alpha.h"
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#include "singlecolourfit.h"
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namespace squish {
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static int FixFlags( int flags )
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{
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// grab the flag bits
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int method = flags & ( kDxt1 | kDxt3 | kDxt5 | kBc4 | kBc5 );
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int fit = flags & ( kColourIterativeClusterFit | kColourClusterFit | kColourRangeFit );
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int extra = flags & kWeightColourByAlpha;
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// set defaults
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if ( method != kDxt3
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&& method != kDxt5
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&& method != kBc4
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&& method != kBc5 )
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{
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method = kDxt1;
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}
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if( fit != kColourRangeFit && fit != kColourIterativeClusterFit )
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fit = kColourClusterFit;
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// done
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return method | fit | extra;
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}
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void CompressMasked( u8 const* rgba, int mask, void* block, int flags, float* metric )
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{
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// fix any bad flags
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flags = FixFlags( flags );
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if ( ( flags & ( kBc4 | kBc5 ) ) != 0 )
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{
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u8 alpha[16*4];
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for( int i = 0; i < 16; ++i )
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{
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alpha[i*4 + 3] = rgba[i*4 + 0]; // copy R to A
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}
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u8* rBlock = reinterpret_cast< u8* >( block );
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CompressAlphaDxt5( alpha, mask, rBlock );
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if ( ( flags & ( kBc5 ) ) != 0 )
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{
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for( int i = 0; i < 16; ++i )
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{
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alpha[i*4 + 3] = rgba[i*4 + 1]; // copy G to A
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}
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u8* gBlock = reinterpret_cast< u8* >( block ) + 8;
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CompressAlphaDxt5( alpha, mask, gBlock );
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}
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return;
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}
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// get the block locations
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void* colourBlock = block;
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void* alphaBlock = block;
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if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
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colourBlock = reinterpret_cast< u8* >( block ) + 8;
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// create the minimal point set
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ColourSet colours( rgba, mask, flags );
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// check the compression type and compress colour
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if( colours.GetCount() == 1 )
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{
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// always do a single colour fit
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SingleColourFit fit( &colours, flags );
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fit.Compress( colourBlock );
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}
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else if( ( flags & kColourRangeFit ) != 0 || colours.GetCount() == 0 )
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{
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// do a range fit
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RangeFit fit( &colours, flags, metric );
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fit.Compress( colourBlock );
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}
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else
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{
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// default to a cluster fit (could be iterative or not)
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ClusterFit fit( &colours, flags, metric );
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fit.Compress( colourBlock );
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}
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// compress alpha separately if necessary
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if( ( flags & kDxt3 ) != 0 )
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CompressAlphaDxt3( rgba, mask, alphaBlock );
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else if( ( flags & kDxt5 ) != 0 )
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CompressAlphaDxt5( rgba, mask, alphaBlock );
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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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// fix any bad flags
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flags = FixFlags( flags );
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// get the block locations
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void const* colourBlock = block;
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void const* alphaBlock = block;
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if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
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colourBlock = reinterpret_cast< u8 const* >( block ) + 8;
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// decompress colour
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DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );
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// decompress alpha separately if necessary
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if( ( flags & kDxt3 ) != 0 )
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DecompressAlphaDxt3( rgba, alphaBlock );
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else if( ( flags & kDxt5 ) != 0 )
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DecompressAlphaDxt5( rgba, alphaBlock );
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}
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int GetStorageRequirements( int width, int height, int flags )
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{
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// fix any bad flags
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flags = FixFlags( flags );
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// compute the storage requirements
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int blockcount = ( ( width + 3 )/4 ) * ( ( height + 3 )/4 );
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int blocksize = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
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return blockcount*blocksize;
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}
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void CopyRGBA( u8 const* source, u8* dest, int flags )
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{
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if (flags & kSourceBGRA)
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{
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// convert from bgra to rgba
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dest[0] = source[2];
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dest[1] = source[1];
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dest[2] = source[0];
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dest[3] = source[3];
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}
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else
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{
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for( int i = 0; i < 4; ++i )
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*dest++ = *source++;
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}
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}
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void CompressImage( u8 const* rgba, int width, int height, int pitch, void* blocks, int flags, float* metric )
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{
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// fix any bad flags
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flags = FixFlags( flags );
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// loop over blocks
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#ifdef SQUISH_USE_OPENMP
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# pragma omp parallel for
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#endif
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for( int y = 0; y < height; y += 4 )
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{
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// initialise the block output
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u8* targetBlock = reinterpret_cast< u8* >( blocks );
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int bytesPerBlock = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
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targetBlock += ( (y / 4) * ( (width + 3) / 4) ) * bytesPerBlock;
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for( int x = 0; x < width; x += 4 )
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{
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// build the 4x4 block of pixels
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u8 sourceRgba[16*4];
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u8* targetPixel = sourceRgba;
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int mask = 0;
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for( int py = 0; py < 4; ++py )
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{
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for( int px = 0; px < 4; ++px )
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{
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// get the source pixel in the image
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int sx = x + px;
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int sy = y + py;
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// enable if we're in the image
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if( sx < width && sy < height )
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{
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// copy the rgba value
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u8 const* sourcePixel = rgba + pitch*sy + 4*sx;
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CopyRGBA(sourcePixel, targetPixel, flags);
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// enable this pixel
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mask |= ( 1 << ( 4*py + px ) );
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}
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// advance to the next pixel
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targetPixel += 4;
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}
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}
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// compress it into the output
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CompressMasked( sourceRgba, mask, targetBlock, flags, metric );
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// advance
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targetBlock += bytesPerBlock;
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}
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}
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}
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void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags, float* metric )
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{
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CompressImage(rgba, width, height, width*4, blocks, flags, metric);
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}
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void DecompressImage( u8* rgba, int width, int height, int pitch, void const* blocks, int flags )
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{
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// fix any bad flags
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flags = FixFlags( flags );
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// loop over blocks
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#ifdef SQUISH_USE_OPENMP
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# pragma omp parallel for
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#endif
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for( int y = 0; y < height; y += 4 )
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{
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// initialise the block input
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u8 const* sourceBlock = reinterpret_cast< u8 const* >( blocks );
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int bytesPerBlock = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
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sourceBlock += ( (y / 4) * ( (width + 3) / 4) ) * bytesPerBlock;
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for( int x = 0; x < width; x += 4 )
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{
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// decompress the block
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u8 targetRgba[4*16];
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Decompress( targetRgba, sourceBlock, flags );
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// write the decompressed pixels to the correct image locations
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u8 const* sourcePixel = targetRgba;
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for( int py = 0; py < 4; ++py )
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{
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for( int px = 0; px < 4; ++px )
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{
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// get the target location
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int sx = x + px;
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int sy = y + py;
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// write if we're in the image
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if( sx < width && sy < height )
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{
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// copy the rgba value
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u8* targetPixel = rgba + pitch*sy + 4*sx;
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CopyRGBA(sourcePixel, targetPixel, flags);
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}
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// advance to the next pixel
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sourcePixel += 4;
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}
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}
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// advance
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sourceBlock += bytesPerBlock;
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}
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}
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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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DecompressImage( rgba, width, height, width*4, blocks, flags );
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}
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static double ErrorSq(double x, double y)
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{
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return (x - y) * (x - y);
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}
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static void ComputeBlockWMSE(u8 const *original, u8 const *compressed, unsigned int w, unsigned int h, double &cmse, double &amse)
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{
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// Computes the MSE for the block and weights it by the variance of the original block.
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// If the variance of the original block is less than 4 (i.e. a standard deviation of 1 per channel)
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// then the block is close to being a single colour. Quantisation errors in single colour blocks
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// are easier to see than similar errors in blocks that contain more colours, particularly when there
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// are many such blocks in a large area (eg a blue sky background) as they cause banding. Given that
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// banding is easier to see than small errors in "complex" blocks, we weight the errors by a factor
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// of 5. This implies that images with large, single colour areas will have a higher potential WMSE
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// than images with lots of detail.
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cmse = amse = 0;
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unsigned int sum_p[4]; // per channel sum of pixels
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unsigned int sum_p2[4]; // per channel sum of pixels squared
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memset(sum_p, 0, sizeof(sum_p));
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memset(sum_p2, 0, sizeof(sum_p2));
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for( unsigned int py = 0; py < 4; ++py )
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{
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for( unsigned int px = 0; px < 4; ++px )
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{
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if( px < w && py < h )
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{
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double pixelCMSE = 0;
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for( int i = 0; i < 3; ++i )
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{
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pixelCMSE += ErrorSq(original[i], compressed[i]);
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sum_p[i] += original[i];
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sum_p2[i] += (unsigned int)original[i]*original[i];
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}
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if( original[3] == 0 && compressed[3] == 0 )
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pixelCMSE = 0; // transparent in both, so colour is inconsequential
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amse += ErrorSq(original[3], compressed[3]);
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cmse += pixelCMSE;
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sum_p[3] += original[3];
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sum_p2[3] += (unsigned int)original[3]*original[3];
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}
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original += 4;
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compressed += 4;
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}
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}
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unsigned int variance = 0;
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for( int i = 0; i < 4; ++i )
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variance += w*h*sum_p2[i] - sum_p[i]*sum_p[i];
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if( variance < 4 * w * w * h * h )
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{
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amse *= 5;
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cmse *= 5;
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}
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}
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void ComputeMSE( u8 const *rgba, int width, int height, int pitch, u8 const *dxt, int flags, double &colourMSE, double &alphaMSE )
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{
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// fix any bad flags
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flags = FixFlags( flags );
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colourMSE = alphaMSE = 0;
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// initialise the block input
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squish::u8 const* sourceBlock = dxt;
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int bytesPerBlock = ( ( flags & squish::kDxt1 ) != 0 ) ? 8 : 16;
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// loop over blocks
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for( int y = 0; y < height; y += 4 )
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{
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for( int x = 0; x < width; x += 4 )
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{
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// decompress the block
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u8 targetRgba[4*16];
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Decompress( targetRgba, sourceBlock, flags );
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u8 const* sourcePixel = targetRgba;
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// copy across to a similar pixel block
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u8 originalRgba[4*16];
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u8* originalPixel = originalRgba;
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for( int py = 0; py < 4; ++py )
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{
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for( int px = 0; px < 4; ++px )
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{
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int sx = x + px;
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int sy = y + py;
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if( sx < width && sy < height )
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{
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u8 const* targetPixel = rgba + pitch*sy + 4*sx;
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CopyRGBA(targetPixel, originalPixel, flags);
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}
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sourcePixel += 4;
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originalPixel += 4;
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}
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}
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// compute the weighted MSE of the block
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double blockCMSE, blockAMSE;
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ComputeBlockWMSE(originalRgba, targetRgba, std::min(4, width - x), std::min(4, height - y), blockCMSE, blockAMSE);
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colourMSE += blockCMSE;
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alphaMSE += blockAMSE;
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// advance
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sourceBlock += bytesPerBlock;
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}
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}
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colourMSE /= (width * height * 3);
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alphaMSE /= (width * height);
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}
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void ComputeMSE( u8 const *rgba, int width, int height, u8 const *dxt, int flags, double &colourMSE, double &alphaMSE )
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{
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ComputeMSE(rgba, width, height, width*4, dxt, flags, colourMSE, alphaMSE);
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}
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} // namespace squish
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