133 lines
4.5 KiB
C++
133 lines
4.5 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 "colourset.h"
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namespace squish {
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ColourSet::ColourSet( u8 const* rgba, int mask, int flags )
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: m_count( 0 ),
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m_transparent( false )
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{
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bool toLinear = ((flags & kToLinear) != 0);
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// check the compression mode for dxt1
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bool isDxt1 = ( ( flags & kDxt1 ) != 0 );
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bool weightByAlpha = ( ( flags & kWeightColourByAlpha ) != 0 );
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// create the minimal set
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for( int i = 0; i < 16; ++i )
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{
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// check this pixel is enabled
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int bit = 1 << i;
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if( ( mask & bit ) == 0 )
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{
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m_remap[i] = -1;
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continue;
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}
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// check for transparent pixels when using dxt1
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if( isDxt1 && rgba[4*i + 3] < 128 )
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{
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m_remap[i] = -1;
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m_transparent = true;
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continue;
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}
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// loop over previous points for a match
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for( int j = 0;; ++j )
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{
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// allocate a new point
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if( j == i )
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{
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// normalise coordinates to [0,1]
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float x = toLinear ?
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SRGBToLinear(( float )rgba[4*i] / 255.0f) :
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( float )rgba[4*i] / 255.0f;
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float y = toLinear ?
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SRGBToLinear(( float )rgba[4*i + 1] / 255.0f) :
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( float )rgba[4*i + 1] / 255.0f;
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float z = toLinear ?
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SRGBToLinear(( float )rgba[4*i + 2] / 255.0f) :
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( float )rgba[4*i + 2] / 255.0f;
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// ensure there is always non-zero weight even for zero alpha
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float w = toLinear != 0 ?
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SRGBToLinear(( float )rgba[4*i + 3] / 256.0f) :
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( float )rgba[4*i + 3] / 256.0f;
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// add the point
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m_points[m_count] = Vec3( x, y, z );
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m_weights[m_count] = ( weightByAlpha ? w : 1.0f );
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m_remap[i] = m_count;
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// advance
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++m_count;
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break;
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}
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// check for a match
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int oldbit = 1 << j;
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bool match = ( ( mask & oldbit ) != 0 )
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&& ( rgba[4*i] == rgba[4*j] )
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&& ( rgba[4*i + 1] == rgba[4*j + 1] )
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&& ( rgba[4*i + 2] == rgba[4*j + 2] )
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&& ( rgba[4*j + 3] >= 128 || !isDxt1 );
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if( match )
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{
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// get the index of the match
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int index = m_remap[j];
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// ensure there is always non-zero weight even for zero alpha
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float w = toLinear != 0 ?
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SRGBToLinear(( float )( rgba[4*i + 3] + 1 ) / 256.0f) :
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( float )( rgba[4*i + 3] + 1 )/ 256.0f;
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// map to this point and increase the weight
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m_weights[index] += ( weightByAlpha ? w : 1.0f );
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m_remap[i] = index;
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break;
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}
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}
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}
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// square root the weights
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for( int i = 0; i < m_count; ++i )
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m_weights[i] = std::sqrt( m_weights[i] );
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}
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void ColourSet::RemapIndices( u8 const* source, u8* target ) const
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{
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for( int i = 0; i < 16; ++i )
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{
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int j = m_remap[i];
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if( j == -1 )
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target[i] = 3;
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else
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target[i] = source[j];
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}
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}
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} // namespace squish
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