diff options
Diffstat (limited to 'thirdparty/squish/alpha.cpp')
| -rw-r--r-- | thirdparty/squish/alpha.cpp | 595 |
1 files changed, 298 insertions, 297 deletions
diff --git a/thirdparty/squish/alpha.cpp b/thirdparty/squish/alpha.cpp index 2292081e7a..7039c1a3b8 100644 --- a/thirdparty/squish/alpha.cpp +++ b/thirdparty/squish/alpha.cpp @@ -1,29 +1,30 @@ /* ----------------------------------------------------------------------------- - 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. - + 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 "alpha.h" + #include <climits> #include <algorithm> @@ -31,319 +32,319 @@ namespace squish { static int FloatToInt( float a, int limit ) { - // use ANSI round-to-zero behaviour to get round-to-nearest - int i = ( int )( a + 0.5f ); + // use ANSI round-to-zero behaviour to get round-to-nearest + int i = ( int )( a + 0.5f ); - // clamp to the limit - if( i < 0 ) - i = 0; - else if( i > limit ) - i = limit; + // clamp to the limit + if( i < 0 ) + i = 0; + else if( i > limit ) + i = limit; - // done - return i; + // done + return i; } void CompressAlphaDxt3( u8 const* rgba, int mask, void* block ) { - u8* bytes = reinterpret_cast< u8* >( block ); - - // quantise and pack the alpha values pairwise - for( int i = 0; i < 8; ++i ) - { - // quantise down to 4 bits - float alpha1 = ( float )rgba[8*i + 3] * ( 15.0f/255.0f ); - float alpha2 = ( float )rgba[8*i + 7] * ( 15.0f/255.0f ); - int quant1 = FloatToInt( alpha1, 15 ); - int quant2 = FloatToInt( alpha2, 15 ); - - // set alpha to zero where masked - int bit1 = 1 << ( 2*i ); - int bit2 = 1 << ( 2*i + 1 ); - if( ( mask & bit1 ) == 0 ) - quant1 = 0; - if( ( mask & bit2 ) == 0 ) - quant2 = 0; - - // pack into the byte - bytes[i] = ( u8 )( quant1 | ( quant2 << 4 ) ); - } + u8* bytes = reinterpret_cast< u8* >( block ); + + // quantise and pack the alpha values pairwise + for( int i = 0; i < 8; ++i ) + { + // quantise down to 4 bits + float alpha1 = ( float )rgba[8*i + 3] * ( 15.0f/255.0f ); + float alpha2 = ( float )rgba[8*i + 7] * ( 15.0f/255.0f ); + int quant1 = FloatToInt( alpha1, 15 ); + int quant2 = FloatToInt( alpha2, 15 ); + + // set alpha to zero where masked + int bit1 = 1 << ( 2*i ); + int bit2 = 1 << ( 2*i + 1 ); + if( ( mask & bit1 ) == 0 ) + quant1 = 0; + if( ( mask & bit2 ) == 0 ) + quant2 = 0; + + // pack into the byte + bytes[i] = ( u8 )( quant1 | ( quant2 << 4 ) ); + } } void DecompressAlphaDxt3( u8* rgba, void const* block ) { - u8 const* bytes = reinterpret_cast< u8 const* >( block ); - - // unpack the alpha values pairwise - for( int i = 0; i < 8; ++i ) - { - // quantise down to 4 bits - u8 quant = bytes[i]; - - // unpack the values - u8 lo = quant & 0x0f; - u8 hi = quant & 0xf0; - - // convert back up to bytes - rgba[8*i + 3] = lo | ( lo << 4 ); - rgba[8*i + 7] = hi | ( hi >> 4 ); - } + u8 const* bytes = reinterpret_cast< u8 const* >( block ); + + // unpack the alpha values pairwise + for( int i = 0; i < 8; ++i ) + { + // quantise down to 4 bits + u8 quant = bytes[i]; + + // unpack the values + u8 lo = quant & 0x0f; + u8 hi = quant & 0xf0; + + // convert back up to bytes + rgba[8*i + 3] = lo | ( lo << 4 ); + rgba[8*i + 7] = hi | ( hi >> 4 ); + } } static void FixRange( int& min, int& max, int steps ) { - if( max - min < steps ) - max = std::min( min + steps, 255 ); - if( max - min < steps ) - min = std::max( 0, max - steps ); + if( max - min < steps ) + max = std::min( min + steps, 255 ); + if( max - min < steps ) + min = std::max( 0, max - steps ); } static int FitCodes( u8 const* rgba, int mask, u8 const* codes, u8* indices ) { - // fit each alpha value to the codebook - int err = 0; - for( int i = 0; i < 16; ++i ) - { - // check this pixel is valid - int bit = 1 << i; - if( ( mask & bit ) == 0 ) - { - // use the first code - indices[i] = 0; - continue; - } - - // find the least error and corresponding index - int value = rgba[4*i + 3]; - int least = INT_MAX; - int index = 0; - for( int j = 0; j < 8; ++j ) - { - // get the squared error from this code - int dist = ( int )value - ( int )codes[j]; - dist *= dist; - - // compare with the best so far - if( dist < least ) - { - least = dist; - index = j; - } - } - - // save this index and accumulate the error - indices[i] = ( u8 )index; - err += least; - } - - // return the total error - return err; + // fit each alpha value to the codebook + int err = 0; + for( int i = 0; i < 16; ++i ) + { + // check this pixel is valid + int bit = 1 << i; + if( ( mask & bit ) == 0 ) + { + // use the first code + indices[i] = 0; + continue; + } + + // find the least error and corresponding index + int value = rgba[4*i + 3]; + int least = INT_MAX; + int index = 0; + for( int j = 0; j < 8; ++j ) + { + // get the squared error from this code + int dist = ( int )value - ( int )codes[j]; + dist *= dist; + + // compare with the best so far + if( dist < least ) + { + least = dist; + index = j; + } + } + + // save this index and accumulate the error + indices[i] = ( u8 )index; + err += least; + } + + // return the total error + return err; } static void WriteAlphaBlock( int alpha0, int alpha1, u8 const* indices, void* block ) { - u8* bytes = reinterpret_cast< u8* >( block ); - - // write the first two bytes - bytes[0] = ( u8 )alpha0; - bytes[1] = ( u8 )alpha1; - - // pack the indices with 3 bits each - u8* dest = bytes + 2; - u8 const* src = indices; - for( int i = 0; i < 2; ++i ) - { - // pack 8 3-bit values - int value = 0; - for( int j = 0; j < 8; ++j ) - { - int index = *src++; - value |= ( index << 3*j ); - } - - // store in 3 bytes - for( int j = 0; j < 3; ++j ) - { - int byte = ( value >> 8*j ) & 0xff; - *dest++ = ( u8 )byte; - } - } + u8* bytes = reinterpret_cast< u8* >( block ); + + // write the first two bytes + bytes[0] = ( u8 )alpha0; + bytes[1] = ( u8 )alpha1; + + // pack the indices with 3 bits each + u8* dest = bytes + 2; + u8 const* src = indices; + for( int i = 0; i < 2; ++i ) + { + // pack 8 3-bit values + int value = 0; + for( int j = 0; j < 8; ++j ) + { + int index = *src++; + value |= ( index << 3*j ); + } + + // store in 3 bytes + for( int j = 0; j < 3; ++j ) + { + int byte = ( value >> 8*j ) & 0xff; + *dest++ = ( u8 )byte; + } + } } static void WriteAlphaBlock5( int alpha0, int alpha1, u8 const* indices, void* block ) { - // check the relative values of the endpoints - if( alpha0 > alpha1 ) - { - // swap the indices - u8 swapped[16]; - for( int i = 0; i < 16; ++i ) - { - u8 index = indices[i]; - if( index == 0 ) - swapped[i] = 1; - else if( index == 1 ) - swapped[i] = 0; - else if( index <= 5 ) - swapped[i] = 7 - index; - else - swapped[i] = index; - } - - // write the block - WriteAlphaBlock( alpha1, alpha0, swapped, block ); - } - else - { - // write the block - WriteAlphaBlock( alpha0, alpha1, indices, block ); - } + // check the relative values of the endpoints + if( alpha0 > alpha1 ) + { + // swap the indices + u8 swapped[16]; + for( int i = 0; i < 16; ++i ) + { + u8 index = indices[i]; + if( index == 0 ) + swapped[i] = 1; + else if( index == 1 ) + swapped[i] = 0; + else if( index <= 5 ) + swapped[i] = 7 - index; + else + swapped[i] = index; + } + + // write the block + WriteAlphaBlock( alpha1, alpha0, swapped, block ); + } + else + { + // write the block + WriteAlphaBlock( alpha0, alpha1, indices, block ); + } } static void WriteAlphaBlock7( int alpha0, int alpha1, u8 const* indices, void* block ) { - // check the relative values of the endpoints - if( alpha0 < alpha1 ) - { - // swap the indices - u8 swapped[16]; - for( int i = 0; i < 16; ++i ) - { - u8 index = indices[i]; - if( index == 0 ) - swapped[i] = 1; - else if( index == 1 ) - swapped[i] = 0; - else - swapped[i] = 9 - index; - } - - // write the block - WriteAlphaBlock( alpha1, alpha0, swapped, block ); - } - else - { - // write the block - WriteAlphaBlock( alpha0, alpha1, indices, block ); - } + // check the relative values of the endpoints + if( alpha0 < alpha1 ) + { + // swap the indices + u8 swapped[16]; + for( int i = 0; i < 16; ++i ) + { + u8 index = indices[i]; + if( index == 0 ) + swapped[i] = 1; + else if( index == 1 ) + swapped[i] = 0; + else + swapped[i] = 9 - index; + } + + // write the block + WriteAlphaBlock( alpha1, alpha0, swapped, block ); + } + else + { + // write the block + WriteAlphaBlock( alpha0, alpha1, indices, block ); + } } void CompressAlphaDxt5( u8 const* rgba, int mask, void* block ) { - // get the range for 5-alpha and 7-alpha interpolation - int min5 = 255; - int max5 = 0; - int min7 = 255; - int max7 = 0; - for( int i = 0; i < 16; ++i ) - { - // check this pixel is valid - int bit = 1 << i; - if( ( mask & bit ) == 0 ) - continue; - - // incorporate into the min/max - int value = rgba[4*i + 3]; - if( value < min7 ) - min7 = value; - if( value > max7 ) - max7 = value; - if( value != 0 && value < min5 ) - min5 = value; - if( value != 255 && value > max5 ) - max5 = value; - } - - // handle the case that no valid range was found - if( min5 > max5 ) - min5 = max5; - if( min7 > max7 ) - min7 = max7; - - // fix the range to be the minimum in each case - FixRange( min5, max5, 5 ); - FixRange( min7, max7, 7 ); - - // set up the 5-alpha code book - u8 codes5[8]; - codes5[0] = ( u8 )min5; - codes5[1] = ( u8 )max5; - for( int i = 1; i < 5; ++i ) - codes5[1 + i] = ( u8 )( ( ( 5 - i )*min5 + i*max5 )/5 ); - codes5[6] = 0; - codes5[7] = 255; - - // set up the 7-alpha code book - u8 codes7[8]; - codes7[0] = ( u8 )min7; - codes7[1] = ( u8 )max7; - for( int i = 1; i < 7; ++i ) - codes7[1 + i] = ( u8 )( ( ( 7 - i )*min7 + i*max7 )/7 ); - - // fit the data to both code books - u8 indices5[16]; - u8 indices7[16]; - int err5 = FitCodes( rgba, mask, codes5, indices5 ); - int err7 = FitCodes( rgba, mask, codes7, indices7 ); - - // save the block with least error - if( err5 <= err7 ) - WriteAlphaBlock5( min5, max5, indices5, block ); - else - WriteAlphaBlock7( min7, max7, indices7, block ); + // get the range for 5-alpha and 7-alpha interpolation + int min5 = 255; + int max5 = 0; + int min7 = 255; + int max7 = 0; + for( int i = 0; i < 16; ++i ) + { + // check this pixel is valid + int bit = 1 << i; + if( ( mask & bit ) == 0 ) + continue; + + // incorporate into the min/max + int value = rgba[4*i + 3]; + if( value < min7 ) + min7 = value; + if( value > max7 ) + max7 = value; + if( value != 0 && value < min5 ) + min5 = value; + if( value != 255 && value > max5 ) + max5 = value; + } + + // handle the case that no valid range was found + if( min5 > max5 ) + min5 = max5; + if( min7 > max7 ) + min7 = max7; + + // fix the range to be the minimum in each case + FixRange( min5, max5, 5 ); + FixRange( min7, max7, 7 ); + + // set up the 5-alpha code book + u8 codes5[8]; + codes5[0] = ( u8 )min5; + codes5[1] = ( u8 )max5; + for( int i = 1; i < 5; ++i ) + codes5[1 + i] = ( u8 )( ( ( 5 - i )*min5 + i*max5 )/5 ); + codes5[6] = 0; + codes5[7] = 255; + + // set up the 7-alpha code book + u8 codes7[8]; + codes7[0] = ( u8 )min7; + codes7[1] = ( u8 )max7; + for( int i = 1; i < 7; ++i ) + codes7[1 + i] = ( u8 )( ( ( 7 - i )*min7 + i*max7 )/7 ); + + // fit the data to both code books + u8 indices5[16]; + u8 indices7[16]; + int err5 = FitCodes( rgba, mask, codes5, indices5 ); + int err7 = FitCodes( rgba, mask, codes7, indices7 ); + + // save the block with least error + if( err5 <= err7 ) + WriteAlphaBlock5( min5, max5, indices5, block ); + else + WriteAlphaBlock7( min7, max7, indices7, block ); } void DecompressAlphaDxt5( u8* rgba, void const* block ) { - // get the two alpha values - u8 const* bytes = reinterpret_cast< u8 const* >( block ); - int alpha0 = bytes[0]; - int alpha1 = bytes[1]; - - // compare the values to build the codebook - u8 codes[8]; - codes[0] = ( u8 )alpha0; - codes[1] = ( u8 )alpha1; - if( alpha0 <= alpha1 ) - { - // use 5-alpha codebook - for( int i = 1; i < 5; ++i ) - codes[1 + i] = ( u8 )( ( ( 5 - i )*alpha0 + i*alpha1 )/5 ); - codes[6] = 0; - codes[7] = 255; - } - else - { - // use 7-alpha codebook - for( int i = 1; i < 7; ++i ) - codes[1 + i] = ( u8 )( ( ( 7 - i )*alpha0 + i*alpha1 )/7 ); - } - - // decode the indices - u8 indices[16]; - u8 const* src = bytes + 2; - u8* dest = indices; - for( int i = 0; i < 2; ++i ) - { - // grab 3 bytes - int value = 0; - for( int j = 0; j < 3; ++j ) - { - int byte = *src++; - value |= ( byte << 8*j ); - } - - // unpack 8 3-bit values from it - for( int j = 0; j < 8; ++j ) - { - int index = ( value >> 3*j ) & 0x7; - *dest++ = ( u8 )index; - } - } - - // write out the indexed codebook values - for( int i = 0; i < 16; ++i ) - rgba[4*i + 3] = codes[indices[i]]; + // get the two alpha values + u8 const* bytes = reinterpret_cast< u8 const* >( block ); + int alpha0 = bytes[0]; + int alpha1 = bytes[1]; + + // compare the values to build the codebook + u8 codes[8]; + codes[0] = ( u8 )alpha0; + codes[1] = ( u8 )alpha1; + if( alpha0 <= alpha1 ) + { + // use 5-alpha codebook + for( int i = 1; i < 5; ++i ) + codes[1 + i] = ( u8 )( ( ( 5 - i )*alpha0 + i*alpha1 )/5 ); + codes[6] = 0; + codes[7] = 255; + } + else + { + // use 7-alpha codebook + for( int i = 1; i < 7; ++i ) + codes[1 + i] = ( u8 )( ( ( 7 - i )*alpha0 + i*alpha1 )/7 ); + } + + // decode the indices + u8 indices[16]; + u8 const* src = bytes + 2; + u8* dest = indices; + for( int i = 0; i < 2; ++i ) + { + // grab 3 bytes + int value = 0; + for( int j = 0; j < 3; ++j ) + { + int byte = *src++; + value |= ( byte << 8*j ); + } + + // unpack 8 3-bit values from it + for( int j = 0; j < 8; ++j ) + { + int index = ( value >> 3*j ) & 0x7; + *dest++ = ( u8 )index; + } + } + + // write out the indexed codebook values + for( int i = 0; i < 16; ++i ) + rgba[4*i + 3] = codes[indices[i]]; } } // namespace squish |