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Diffstat (limited to 'thirdparty/squish/rangefit.cpp')
| -rw-r--r-- | thirdparty/squish/rangefit.cpp | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/thirdparty/squish/rangefit.cpp b/thirdparty/squish/rangefit.cpp new file mode 100644 index 0000000000..adc07ed7d2 --- /dev/null +++ b/thirdparty/squish/rangefit.cpp @@ -0,0 +1,201 @@ +/* ----------------------------------------------------------------------------- + + 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 "rangefit.h" +#include "colourset.h" +#include "colourblock.h" +#include <cfloat> + +namespace squish { + +RangeFit::RangeFit( ColourSet const* colours, int flags, float* metric ) + : ColourFit( colours, flags ) +{ + // initialise the metric (old perceptual = 0.2126f, 0.7152f, 0.0722f) + if( metric ) + m_metric = Vec3( metric[0], metric[1], metric[2] ); + else + m_metric = Vec3( 1.0f ); + + // initialise the best error + m_besterror = FLT_MAX; + + // cache some values + int const count = m_colours->GetCount(); + Vec3 const* values = m_colours->GetPoints(); + float const* weights = m_colours->GetWeights(); + + // get the covariance matrix + Sym3x3 covariance = ComputeWeightedCovariance( count, values, weights ); + + // compute the principle component + Vec3 principle = ComputePrincipleComponent( covariance ); + + // get the min and max range as the codebook endpoints + Vec3 start( 0.0f ); + Vec3 end( 0.0f ); + if( count > 0 ) + { + float min, max; + + // compute the range + start = end = values[0]; + min = max = Dot( values[0], principle ); + for( int i = 1; i < count; ++i ) + { + float val = Dot( values[i], principle ); + if( val < min ) + { + start = values[i]; + min = val; + } + else if( val > max ) + { + end = values[i]; + max = val; + } + } + } + + // clamp the output to [0, 1] + Vec3 const one( 1.0f ); + Vec3 const zero( 0.0f ); + start = Min( one, Max( zero, start ) ); + end = Min( one, Max( zero, end ) ); + + // clamp to the grid and save + Vec3 const grid( 31.0f, 63.0f, 31.0f ); + Vec3 const gridrcp( 1.0f/31.0f, 1.0f/63.0f, 1.0f/31.0f ); + Vec3 const half( 0.5f ); + m_start = Truncate( grid*start + half )*gridrcp; + m_end = Truncate( grid*end + half )*gridrcp; +} + +void RangeFit::Compress3( void* block ) +{ + // cache some values + int const count = m_colours->GetCount(); + Vec3 const* values = m_colours->GetPoints(); + + // create a codebook + Vec3 codes[3]; + codes[0] = m_start; + codes[1] = m_end; + codes[2] = 0.5f*m_start + 0.5f*m_end; + + // match each point to the closest code + u8 closest[16]; + float error = 0.0f; + for( int i = 0; i < count; ++i ) + { + // find the closest code + float dist = FLT_MAX; + int idx = 0; + for( int j = 0; j < 3; ++j ) + { + float d = LengthSquared( m_metric*( values[i] - codes[j] ) ); + if( d < dist ) + { + dist = d; + idx = j; + } + } + + // save the index + closest[i] = ( u8 )idx; + + // accumulate the error + error += dist; + } + + // save this scheme if it wins + if( error < m_besterror ) + { + // remap the indices + u8 indices[16]; + m_colours->RemapIndices( closest, indices ); + + // save the block + WriteColourBlock3( m_start, m_end, indices, block ); + + // save the error + m_besterror = error; + } +} + +void RangeFit::Compress4( void* block ) +{ + // cache some values + int const count = m_colours->GetCount(); + Vec3 const* values = m_colours->GetPoints(); + + // create a codebook + Vec3 codes[4]; + codes[0] = m_start; + codes[1] = m_end; + codes[2] = ( 2.0f/3.0f )*m_start + ( 1.0f/3.0f )*m_end; + codes[3] = ( 1.0f/3.0f )*m_start + ( 2.0f/3.0f )*m_end; + + // match each point to the closest code + u8 closest[16]; + float error = 0.0f; + for( int i = 0; i < count; ++i ) + { + // find the closest code + float dist = FLT_MAX; + int idx = 0; + for( int j = 0; j < 4; ++j ) + { + float d = LengthSquared( m_metric*( values[i] - codes[j] ) ); + if( d < dist ) + { + dist = d; + idx = j; + } + } + + // save the index + closest[i] = ( u8 )idx; + + // accumulate the error + error += dist; + } + + // save this scheme if it wins + if( error < m_besterror ) + { + // remap the indices + u8 indices[16]; + m_colours->RemapIndices( closest, indices ); + + // save the block + WriteColourBlock4( m_start, m_end, indices, block ); + + // save the error + m_besterror = error; + } +} + +} // namespace squish |