colourset.cc (3491B)
1 /* ----------------------------------------------------------------------------- 2 3 Copyright (c) 2006 Simon Brown si@sjbrown.co.uk 4 5 Permission is hereby granted, free of charge, to any person obtaining 6 a copy of this software and associated documentation files (the 7 "Software"), to deal in the Software without restriction, including 8 without limitation the rights to use, copy, modify, merge, publish, 9 distribute, sublicense, and/or sell copies of the Software, and to 10 permit persons to whom the Software is furnished to do so, subject to 11 the following conditions: 12 13 The above copyright notice and this permission notice shall be included 14 in all copies or substantial portions of the Software. 15 16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 17 OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 19 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 20 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 21 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 22 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 24 -------------------------------------------------------------------------- */ 25 26 #include "colourset.h" 27 28 namespace squish { 29 30 ColourSet::ColourSet( u8 const* rgba, int mask, int flags ) 31 : m_count( 0 ), 32 m_transparent( false ) 33 { 34 // check the compression mode for dxt1 35 bool isDxt1 = ( ( flags & kDxt1 ) != 0 ); 36 bool weightByAlpha = ( ( flags & kWeightColourByAlpha ) != 0 ); 37 38 // create the minimal set 39 for( int i = 0; i < 16; ++i ) 40 { 41 // check this pixel is enabled 42 int bit = 1 << i; 43 if( ( mask & bit ) == 0 ) 44 { 45 m_remap[i] = -1; 46 continue; 47 } 48 49 // check for transparent pixels when using dxt1 50 if( isDxt1 && rgba[4*i + 3] < 128 ) 51 { 52 m_remap[i] = -1; 53 m_transparent = true; 54 continue; 55 } 56 57 // loop over previous points for a match 58 for( int j = 0;; ++j ) 59 { 60 // allocate a new point 61 if( j == i ) 62 { 63 // normalise coordinates to [0,1] 64 float x = ( float )rgba[4*i] / 255.0f; 65 float y = ( float )rgba[4*i + 1] / 255.0f; 66 float z = ( float )rgba[4*i + 2] / 255.0f; 67 68 // ensure there is always non-zero weight even for zero alpha 69 float w = ( float )( rgba[4*i + 3] + 1 ) / 256.0f; 70 71 // add the point 72 m_points[m_count] = Vec3( x, y, z ); 73 m_weights[m_count] = ( weightByAlpha ? w : 1.0f ); 74 m_remap[i] = m_count; 75 76 // advance 77 ++m_count; 78 break; 79 } 80 81 // check for a match 82 int oldbit = 1 << j; 83 bool match = ( ( mask & oldbit ) != 0 ) 84 && ( rgba[4*i] == rgba[4*j] ) 85 && ( rgba[4*i + 1] == rgba[4*j + 1] ) 86 && ( rgba[4*i + 2] == rgba[4*j + 2] ) 87 && ( rgba[4*j + 3] >= 128 || !isDxt1 ); 88 if( match ) 89 { 90 // get the index of the match 91 int index = m_remap[j]; 92 93 // ensure there is always non-zero weight even for zero alpha 94 float w = ( float )( rgba[4*i + 3] + 1 ) / 256.0f; 95 96 // map to this point and increase the weight 97 m_weights[index] += ( weightByAlpha ? w : 1.0f ); 98 m_remap[i] = index; 99 break; 100 } 101 } 102 } 103 104 // square root the weights 105 for( int i = 0; i < m_count; ++i ) 106 m_weights[i] = std::sqrt( m_weights[i] ); 107 } 108 109 void ColourSet::RemapIndices( u8 const* source, u8* target ) const 110 { 111 for( int i = 0; i < 16; ++i ) 112 { 113 int j = m_remap[i]; 114 if( j == -1 ) 115 target[i] = 3; 116 else 117 target[i] = source[j]; 118 } 119 } 120 121 } // namespace squish