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-rw-r--r--drivers/squish/alpha.cpp348
1 files changed, 0 insertions, 348 deletions
diff --git a/drivers/squish/alpha.cpp b/drivers/squish/alpha.cpp
deleted file mode 100644
index 2ddb7dc28b..0000000000
--- a/drivers/squish/alpha.cpp
+++ /dev/null
@@ -1,348 +0,0 @@
-/* -----------------------------------------------------------------------------
-
- 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 <algorithm>
-
-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 );
-
- // clamp to the limit
- if( i < 0 )
- i = 0;
- else if( i > limit )
- i = limit;
-
- // 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 ) );
- }
-}
-
-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 );
- }
-}
-
-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 );
-}
-
-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 = 2147483647; //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;
- }
- }
-}
-
-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 );
- }
-}
-
-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 );
- }
-}
-
-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 );
-}
-
-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]];
-}
-
-} // namespace squish
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