Import code from previous AssetBuilder version

thirdparty/libsquish/singlecolourfit.cpp

@@ -0,0 +1,172 @@
+/* -----------------------------------------------------------------------------
+
+    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 "singlecolourfit.h"
+#include "colourset.h"
+#include "colourblock.h"
+
+namespace squish {
+
+struct SourceBlock
+{
+    u8 start;
+    u8 end;
+    u8 error;
+};
+
+struct SingleColourLookup
+{
+    SourceBlock sources[2];
+};
+
+#include "singlecolourlookup.inl"
+
+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;
+}
+
+SingleColourFit::SingleColourFit( ColourSet const* colours, int flags )
+  : ColourFit( colours, flags )
+{
+    // grab the single colour
+    Vec3 const* values = m_colours->GetPoints();
+    m_colour[0] = ( u8 )FloatToInt( 255.0f*values->X(), 255 );
+    m_colour[1] = ( u8 )FloatToInt( 255.0f*values->Y(), 255 );
+    m_colour[2] = ( u8 )FloatToInt( 255.0f*values->Z(), 255 );
+
+    // initialise the best error
+    m_besterror = INT_MAX;
+}
+
+void SingleColourFit::Compress3( void* block )
+{
+    // build the table of lookups
+    SingleColourLookup const* const lookups[] =
+    {
+        lookup_5_3,
+        lookup_6_3,
+        lookup_5_3
+    };
+
+    // find the best end-points and index
+    ComputeEndPoints( lookups );
+
+    // build the block if we win
+    if( m_error < m_besterror )
+    {
+        // remap the indices
+        u8 indices[16];
+        m_colours->RemapIndices( &m_index, indices );
+
+        // save the block
+        WriteColourBlock3( m_start, m_end, indices, block );
+
+        // save the error
+        m_besterror = m_error;
+    }
+}
+
+void SingleColourFit::Compress4( void* block )
+{
+    // build the table of lookups
+    SingleColourLookup const* const lookups[] =
+    {
+        lookup_5_4,
+        lookup_6_4,
+        lookup_5_4
+    };
+
+    // find the best end-points and index
+    ComputeEndPoints( lookups );
+
+    // build the block if we win
+    if( m_error < m_besterror )
+    {
+        // remap the indices
+        u8 indices[16];
+        m_colours->RemapIndices( &m_index, indices );
+
+        // save the block
+        WriteColourBlock4( m_start, m_end, indices, block );
+
+        // save the error
+        m_besterror = m_error;
+    }
+}
+
+void SingleColourFit::ComputeEndPoints( SingleColourLookup const* const* lookups )
+{
+    // check each index combination (endpoint or intermediate)
+    m_error = INT_MAX;
+    for( int index = 0; index < 2; ++index )
+    {
+        // check the error for this codebook index
+        SourceBlock const* sources[3];
+        int error = 0;
+        for( int channel = 0; channel < 3; ++channel )
+        {
+            // grab the lookup table and index for this channel
+            SingleColourLookup const* lookup = lookups[channel];
+            int target = m_colour[channel];
+
+            // store a pointer to the source for this channel
+            sources[channel] = lookup[target].sources + index;
+
+            // accumulate the error
+            int diff = sources[channel]->error;
+            error += diff*diff;
+        }
+
+        // keep it if the error is lower
+        if( error < m_error )
+        {
+            m_start = Vec3(
+                ( float )sources[0]->start/31.0f,
+                ( float )sources[1]->start/63.0f,
+                ( float )sources[2]->start/31.0f
+            );
+            m_end = Vec3(
+                ( float )sources[0]->end/31.0f,
+                ( float )sources[1]->end/63.0f,
+                ( float )sources[2]->end/31.0f
+            );
+            m_index = ( u8 )( 2*index );
+            m_error = error;
+        }
+    }
+}
+
+} // namespace squish