text: /* -----------------------------------------------------------------------------
  
  	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 "colourset.h"
  
  namespace nvsquish {
  
  // @@ Add flags:
  // - MatchTransparent
  // - WeightColorByAlpha
  
  	
  ColourSet::ColourSet( u8 const* rgba, int flags, bool createMinimalSet/*=false*/ )
    : m_count( 0 ), 
  	m_transparent( false )
  {
  	// check the compression mode for dxt1
  	bool isDxt1 = ( ( flags & kDxt1 ) != 0 );
  	bool weightByAlpha = ( ( flags & kWeightColourByAlpha ) != 0 );
  
  	// create the minimal set
  	for( int i = 0; i < 16; ++i )
  	{
  		if (createMinimalSet)
  		{
  			// check for transparent pixels when using dxt1
  			if( isDxt1 && rgba[4*i + 3] == 0 )
  			{
  				m_remap[i] = -1;
  				m_transparent = true;
  				continue;
  			}
  
  			// loop over previous points for a match
  			for( int j = 0;; ++j )
  			{
  				// allocate a new point
  				if( j == i )
  				{
  					// normalise coordinates to [0,1]
  					float x = ( float )rgba[4*i + 2] / 255.0f;
  					float y = ( float )rgba[4*i + 1] / 255.0f;
  					float z = ( float )rgba[4*i + 0] / 255.0f;
  					
  					// ensure there is always non-zero weight even for zero alpha
  					float w = ( float )( rgba[4*i + 3] + 1 ) / 256.0f;
  
  					// add the point
  					m_points[m_count] = Vec3( x, y, z );
  					m_weights[m_count] = ( weightByAlpha ? w : 1.0f );
  					m_remap[i] = m_count;
  					
  					// advance
  					++m_count;
  					break;
  				}
  			
  				// check for a match
  				bool match = ( rgba[4*i] == rgba[4*j] )
  					&& ( rgba[4*i + 1] == rgba[4*j + 1] )
  					&& ( rgba[4*i + 2] == rgba[4*j + 2] )
  					&& ( rgba[4*j + 3] != 0 || !isDxt1 ); // @@ I think this check is not necessary.
  
  				if( match )
  				{
  					// get the index of the match
  					int index = m_remap[j];
  					
  					// ensure there is always non-zero weight even for zero alpha
  					float w = ( float )( rgba[4*i + 3] + 1 ) / 256.0f;
  
  					// map to this point and increase the weight
  					m_weights[index] += ( weightByAlpha ? w : 1.0f );
  					m_remap[i] = index;
  					break;
  				}
  			}
  		}
  		else
  		{
  			// check for transparent pixels when using dxt1
  			if( isDxt1 && rgba[4*i + 3] == 0 )
  			{
  				m_remap[i] = -1;
  				m_transparent = true;
  			}
  			else
  			{
  				m_remap[i] = m_count;
  			}
  
  			// normalise coordinates to [0,1]
  			float x = ( float )rgba[4*i + 2] / 255.0f;
  			float y = ( float )rgba[4*i + 1] / 255.0f;
  			float z = ( float )rgba[4*i + 0] / 255.0f;
  			
  			// ensure there is always non-zero weight even for zero alpha
  			float w = ( float )( rgba[4*i + 3] + 1 ) / 256.0f;
  
  			// add the point
  			m_points[m_count] = Vec3( x, y, z );
  			m_weights[m_count] = ( weightByAlpha ? w : 1.0f );
  			
  			// advance
  			++m_count;
  		}
  	}
  	
  #if SQUISH_USE_SIMD
  	// generate vector values
  	for( int i = 0; i < m_count; ++i )
  	{
  		m_points_simd[i] = Vec4(m_points[i].X(), m_points[i].Y(), m_points[i].Z(), 1);
  		m_weights_simd[i] = VEC4_CONST(m_weights[i]);
  	}
  #endif
  }
  
  void ColourSet::RemapIndices( u8 const* source, u8* target ) const
  {
  	for( int i = 0; i < 16; ++i )
  	{
  		int j = m_remap[i];
  		if( j == -1 )
  			target[i] = 3;
  		else
  			target[i] = source[j];
  	}
  }
  
  } // namespace squish
  