godot/thirdparty/squish/squish.cpp
Rémi Verschelde 249836e530 squish: Update to upstream 1.14
Sources are untouched, tarball from https://sourceforge.net/projects/libsquish
2016-10-15 12:01:28 +02:00

396 lines
13 KiB
C++

/* -----------------------------------------------------------------------------
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 <string.h>
#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* alphaBlock = 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, alphaBlock );
else if( ( flags & kDxt5 ) != 0 )
DecompressAlphaDxt5( rgba, alphaBlock );
}
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 CopyRGBA( u8 const* source, u8* dest, int flags )
{
if (flags & kSourceBGRA)
{
// convert from bgra to rgba
dest[0] = source[2];
dest[1] = source[1];
dest[2] = source[0];
dest[3] = source[3];
}
else
{
for( int i = 0; i < 4; ++i )
*dest++ = *source++;
}
}
void CompressImage( u8 const* rgba, int width, int height, int pitch, 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 + pitch*sy + 4*sx;
CopyRGBA(sourcePixel, targetPixel, flags);
// enable this pixel
mask |= ( 1 << ( 4*py + px ) );
}
// advance to the next pixel
targetPixel += 4;
}
}
// compress it into the output
CompressMasked( sourceRgba, mask, targetBlock, flags, metric );
// advance
targetBlock += bytesPerBlock;
}
}
}
void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags, float* metric )
{
CompressImage(rgba, width, height, width*4, blocks, flags, metric);
}
void DecompressImage( u8* rgba, int width, int height, int pitch, 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;
// write if we're in the image
if( sx < width && sy < height )
{
// copy the rgba value
u8* targetPixel = rgba + pitch*sy + 4*sx;
CopyRGBA(sourcePixel, targetPixel, flags);
}
// advance to the next pixel
sourcePixel += 4;
}
}
// advance
sourceBlock += bytesPerBlock;
}
}
}
void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags )
{
DecompressImage( rgba, width, height, width*4, blocks, flags );
}
static double ErrorSq(double x, double y)
{
return (x - y) * (x - y);
}
static void ComputeBlockWMSE(u8 const *original, u8 const *compressed, unsigned int w, unsigned int h, double &cmse, double &amse)
{
// Computes the MSE for the block and weights it by the variance of the original block.
// If the variance of the original block is less than 4 (i.e. a standard deviation of 1 per channel)
// then the block is close to being a single colour. Quantisation errors in single colour blocks
// are easier to see than similar errors in blocks that contain more colours, particularly when there
// are many such blocks in a large area (eg a blue sky background) as they cause banding. Given that
// banding is easier to see than small errors in "complex" blocks, we weight the errors by a factor
// of 5. This implies that images with large, single colour areas will have a higher potential WMSE
// than images with lots of detail.
cmse = amse = 0;
unsigned int sum_p[4]; // per channel sum of pixels
unsigned int sum_p2[4]; // per channel sum of pixels squared
memset(sum_p, 0, sizeof(sum_p));
memset(sum_p2, 0, sizeof(sum_p2));
for( unsigned int py = 0; py < 4; ++py )
{
for( unsigned int px = 0; px < 4; ++px )
{
if( px < w && py < h )
{
double pixelCMSE = 0;
for( int i = 0; i < 3; ++i )
{
pixelCMSE += ErrorSq(original[i], compressed[i]);
sum_p[i] += original[i];
sum_p2[i] += (unsigned int)original[i]*original[i];
}
if( original[3] == 0 && compressed[3] == 0 )
pixelCMSE = 0; // transparent in both, so colour is inconsequential
amse += ErrorSq(original[3], compressed[3]);
cmse += pixelCMSE;
sum_p[3] += original[3];
sum_p2[3] += (unsigned int)original[3]*original[3];
}
original += 4;
compressed += 4;
}
}
unsigned int variance = 0;
for( int i = 0; i < 4; ++i )
variance += w*h*sum_p2[i] - sum_p[i]*sum_p[i];
if( variance < 4 * w * w * h * h )
{
amse *= 5;
cmse *= 5;
}
}
void ComputeMSE( u8 const *rgba, int width, int height, int pitch, u8 const *dxt, int flags, double &colourMSE, double &alphaMSE )
{
// fix any bad flags
flags = FixFlags( flags );
colourMSE = alphaMSE = 0;
// initialise the block input
squish::u8 const* sourceBlock = dxt;
int bytesPerBlock = ( ( flags & squish::kDxt1 ) != 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 );
u8 const* sourcePixel = targetRgba;
// copy across to a similar pixel block
u8 originalRgba[4*16];
u8* originalPixel = originalRgba;
for( int py = 0; py < 4; ++py )
{
for( int px = 0; px < 4; ++px )
{
int sx = x + px;
int sy = y + py;
if( sx < width && sy < height )
{
u8 const* targetPixel = rgba + pitch*sy + 4*sx;
CopyRGBA(targetPixel, originalPixel, flags);
}
sourcePixel += 4;
originalPixel += 4;
}
}
// compute the weighted MSE of the block
double blockCMSE, blockAMSE;
ComputeBlockWMSE(originalRgba, targetRgba, std::min(4, width - x), std::min(4, height - y), blockCMSE, blockAMSE);
colourMSE += blockCMSE;
alphaMSE += blockAMSE;
// advance
sourceBlock += bytesPerBlock;
}
}
colourMSE /= (width * height * 3);
alphaMSE /= (width * height);
}
void ComputeMSE( u8 const *rgba, int width, int height, u8 const *dxt, int flags, double &colourMSE, double &alphaMSE )
{
ComputeMSE(rgba, width, height, width*4, dxt, flags, colourMSE, alphaMSE);
}
} // namespace squish