medfall

squish.cc (7017B)

---

 /* -----------------------------------------------------------------------------
 
 	Copyright (c) 2006 Simon Brown                          si@sjbrown.co.uk
 
 	Permission is hereby granted, free of charge, to any person obtaining
 	a copy of this software and associated documentation files (the 
 	"Software"), to	deal in the Software without restriction, including
 	without limitation the rights to use, copy, modify, merge, publish,
 	distribute, sublicense, and/or sell copies of the Software, and to 
 	permit persons to whom the Software is furnished to do so, subject to 
 	the following conditions:
 
 	The above copyright notice and this permission notice shall be included
 	in all copies or substantial portions of the Software.
 
 	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 	OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
 	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 	IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 
 	CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 	TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
 	SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 	
    -------------------------------------------------------------------------- */
    
 #include "squish.h"
 #include "colourset.h"
 #include "maths.h"
 #include "rangefit.h"
 #include "clusterfit.h"
 #include "colourblock.h"
 #include "alpha.h"
 #include "singlecolourfit.h"
 
 namespace squish {
 
 static int FixFlags( int flags )
 {
 	// grab the flag bits
 	int method = flags & ( kDxt1 | kDxt3 | kDxt5 | kBc4 | kBc5 );
 	int fit = flags & ( kColourIterativeClusterFit | kColourClusterFit | kColourRangeFit );
 	int extra = flags & kWeightColourByAlpha;
 	
 	// set defaults
 	if ( method != kDxt3
 	&&   method != kDxt5
 	&&   method != kBc4
 	&&   method != kBc5 )
 	{
 		method = kDxt1;
 	}
 	if( fit != kColourRangeFit && fit != kColourIterativeClusterFit )
 		fit = kColourClusterFit;
 		
 	// done
 	return method | fit | extra;
 }
 
 void CompressMasked( u8 const* rgba, int mask, void* block, int flags, float* metric )
 {
 	// fix any bad flags
 	flags = FixFlags( flags );
 
 	if ( ( flags & ( kBc4 | kBc5 ) ) != 0 )
 	{
 		u8 alpha[16*4];
 		for( int i = 0; i < 16; ++i )
 		{
 			alpha[i*4 + 3] = rgba[i*4 + 0]; // copy R to A
 		}
 
 		u8* rBlock = reinterpret_cast< u8* >( block );
 		CompressAlphaDxt5( alpha, mask, rBlock );
 
 		if ( ( flags & ( kBc5 ) ) != 0 )
 		{
 			for( int i = 0; i < 16; ++i )
 			{
 				alpha[i*4 + 3] = rgba[i*4 + 1]; // copy G to A
 			}
 
 			u8* gBlock = reinterpret_cast< u8* >( block ) + 8;
 			CompressAlphaDxt5( alpha, mask, gBlock );
 		}
 
 		return;
 	}
 
 	// get the block locations
 	void* colourBlock = block;
 	void* alphaBlock = block;
 	if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
 		colourBlock = reinterpret_cast< u8* >( block ) + 8;
 
 	// create the minimal point set
 	ColourSet colours( rgba, mask, flags );
 	
 	// check the compression type and compress colour
 	if( colours.GetCount() == 1 )
 	{
 		// always do a single colour fit
 		SingleColourFit fit( &colours, flags );
 		fit.Compress( colourBlock );
 	}
 	else if( ( flags & kColourRangeFit ) != 0 || colours.GetCount() == 0 )
 	{
 		// do a range fit
 		RangeFit fit( &colours, flags, metric );
 		fit.Compress( colourBlock );
 	}
 	else
 	{
 		// default to a cluster fit (could be iterative or not)
 		ClusterFit fit( &colours, flags, metric );
 		fit.Compress( colourBlock );
 	}
 	
 	// compress alpha separately if necessary
 	if( ( flags & kDxt3 ) != 0 )
 		CompressAlphaDxt3( rgba, mask, alphaBlock );
 	else if( ( flags & kDxt5 ) != 0 )
 		CompressAlphaDxt5( rgba, mask, alphaBlock );
 }
 
 void Decompress( u8* rgba, void const* block, int flags )
 {
 	// fix any bad flags
 	flags = FixFlags( flags );
 
 	// get the block locations
 	void const* colourBlock = block;
 	void const* alphaBock = block;
 	if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
 		colourBlock = reinterpret_cast< u8 const* >( block ) + 8;
 
 	// decompress colour
 	DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );
 
 	// decompress alpha separately if necessary
 	if( ( flags & kDxt3 ) != 0 )
 		DecompressAlphaDxt3( rgba, alphaBock );
 	else if( ( flags & kDxt5 ) != 0 )
 		DecompressAlphaDxt5( rgba, alphaBock );
 }
 
 int GetStorageRequirements( int width, int height, int flags )
 {
 	// fix any bad flags
 	flags = FixFlags( flags );
 	
 	// compute the storage requirements
 	int blockcount = ( ( width + 3 )/4 ) * ( ( height + 3 )/4 );
 	int blocksize = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
 	return blockcount*blocksize;
 }
 
 void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags, float* metric )
 {
 	// fix any bad flags
 	flags = FixFlags( flags );
 
 	// initialise the block output
 	u8* targetBlock = reinterpret_cast< u8* >( blocks );
 	int bytesPerBlock = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
 
 	// loop over blocks
 	for( int y = 0; y < height; y += 4 )
 	{
 		for( int x = 0; x < width; x += 4 )
 		{
 			// build the 4x4 block of pixels
 			u8 sourceRgba[16*4];
 			u8* targetPixel = sourceRgba;
 			int mask = 0;
 			for( int py = 0; py < 4; ++py )
 			{
 				for( int px = 0; px < 4; ++px )
 				{
 					// get the source pixel in the image
 					int sx = x + px;
 					int sy = y + py;
 					
 					// enable if we're in the image
 					if( sx < width && sy < height )
 					{
 						// copy the rgba value
 						u8 const* sourcePixel = rgba + 4*( width*sy + sx );
 						for( int i = 0; i < 4; ++i )
 							*targetPixel++ = *sourcePixel++;
 							
 						// enable this pixel
 						mask |= ( 1 << ( 4*py + px ) );
 					}
 					else
 					{
 						// skip this pixel as its outside the image
 						targetPixel += 4;
 					}
 				}
 			}
 			
 			// compress it into the output
 			CompressMasked( sourceRgba, mask, targetBlock, flags, metric );
 			
 			// advance
 			targetBlock += bytesPerBlock;
 		}
 	}
 }
 
 void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags )
 {
 	// fix any bad flags
 	flags = FixFlags( flags );
 
 	// initialise the block input
 	u8 const* sourceBlock = reinterpret_cast< u8 const* >( blocks );
 	int bytesPerBlock = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;
 
 	// loop over blocks
 	for( int y = 0; y < height; y += 4 )
 	{
 		for( int x = 0; x < width; x += 4 )
 		{
 			// decompress the block
 			u8 targetRgba[4*16];
 			Decompress( targetRgba, sourceBlock, flags );
 			
 			// write the decompressed pixels to the correct image locations
 			u8 const* sourcePixel = targetRgba;
 			for( int py = 0; py < 4; ++py )
 			{
 				for( int px = 0; px < 4; ++px )
 				{
 					// get the target location
 					int sx = x + px;
 					int sy = y + py;
 					if( sx < width && sy < height )
 					{
 						u8* targetPixel = rgba + 4*( width*sy + sx );
 						
 						// copy the rgba value
 						for( int i = 0; i < 4; ++i )
 							*targetPixel++ = *sourcePixel++;
 					}
 					else
 					{
 						// skip this pixel as its outside the image
 						sourcePixel += 4;
 					}
 				}
 			}
 			
 			// advance
 			sourceBlock += bytesPerBlock;
 		}
 	}
 }
 
 } // namespace squish