241 lines
7.8 KiB
C++
241 lines
7.8 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 "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 | kAti2 );
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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 && method != kDxt5 && method != kAti2 )
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method = kDxt1;
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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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// get the block locations
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void* colourBlock = block;
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void* alphaBock = block;
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if( ( flags & ( kDxt3 | kDxt5 | kAti2 ) ) != 0 )
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colourBlock = reinterpret_cast< u8* >( block ) + 8;
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if( ( flags & kAti2 ) != 0 )
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{
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CompressAlphaDxt5( rgba, mask, colourBlock );
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}
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else
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{
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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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}
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// compress alpha separately if necessary
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if( ( flags & kDxt3 ) != 0 )
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CompressAlphaDxt3( rgba, mask, alphaBock );
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else if( ( flags & kDxt5 ) != 0 )
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CompressAlphaDxt5( rgba, mask, alphaBock );
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else if( ( flags & kAti2 ) != 0 )
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CompressAlphaDxt5( rgba, mask, alphaBock, 1 ); // interpret green channel as alpha
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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* alphaBock = 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, alphaBock );
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else if( ( flags & kDxt5 ) != 0 )
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DecompressAlphaDxt5( rgba, alphaBock );
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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 ) != 0 ) ? 8 : 16;
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return blockcount*blocksize;
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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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// fix any bad flags
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flags = FixFlags( flags );
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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 ) != 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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// 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 + 4*( width*sy + sx );
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for( int i = 0; i < 4; ++i )
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*targetPixel++ = *sourcePixel++;
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// enable this pixel
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mask |= ( 1 << ( 4*py + px ) );
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}
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else
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{
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// skip this pixel as its outside the image
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targetPixel += 4;
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}
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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 DecompressImage( u8* rgba, int width, int height, 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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// initialise the block input
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u8 const* sourceBlock = reinterpret_cast< u8 const* >( blocks );
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int bytesPerBlock = ( ( flags & 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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// 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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if( sx < width && sy < height )
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{
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u8* targetPixel = rgba + 4*( width*sy + sx );
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// copy the rgba value
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for( int i = 0; i < 4; ++i )
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*targetPixel++ = *sourcePixel++;
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}
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else
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{
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// skip this pixel as its outside the image
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sourcePixel += 4;
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}
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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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} // namespace squish
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