Import code from previous AssetBuilder version

thirdparty/libsquish/colourblock.cpp

@@ -0,0 +1,214 @@
+/* -----------------------------------------------------------------------------
+
+    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 "colourblock.h"
+
+namespace squish {
+
+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;
+}
+
+static int FloatTo565( Vec3::Arg colour )
+{
+    // get the components in the correct range
+    int r = FloatToInt( 31.0f*colour.X(), 31 );
+    int g = FloatToInt( 63.0f*colour.Y(), 63 );
+    int b = FloatToInt( 31.0f*colour.Z(), 31 );
+
+    // pack into a single value
+    return ( r << 11 ) | ( g << 5 ) | b;
+}
+
+static void WriteColourBlock( int a, int b, u8* indices, void* block )
+{
+    // get the block as bytes
+    u8* bytes = ( u8* )block;
+
+    // write the endpoints
+    bytes[0] = ( u8 )( a & 0xff );
+    bytes[1] = ( u8 )( a >> 8 );
+    bytes[2] = ( u8 )( b & 0xff );
+    bytes[3] = ( u8 )( b >> 8 );
+
+    // write the indices
+    for( int i = 0; i < 4; ++i )
+    {
+        u8 const* ind = indices + 4*i;
+        bytes[4 + i] = ind[0] | ( ind[1] << 2 ) | ( ind[2] << 4 ) | ( ind[3] << 6 );
+    }
+}
+
+void WriteColourBlock3( Vec3::Arg start, Vec3::Arg end, u8 const* indices, void* block )
+{
+    // get the packed values
+    int a = FloatTo565( start );
+    int b = FloatTo565( end );
+
+    // remap the indices
+    u8 remapped[16];
+    if( a <= b )
+    {
+        // use the indices directly
+        for( int i = 0; i < 16; ++i )
+            remapped[i] = indices[i];
+    }
+    else
+    {
+        // swap a and b
+        std::swap( a, b );
+        for( int i = 0; i < 16; ++i )
+        {
+            if( indices[i] == 0 )
+                remapped[i] = 1;
+            else if( indices[i] == 1 )
+                remapped[i] = 0;
+            else
+                remapped[i] = indices[i];
+        }
+    }
+
+    // write the block
+    WriteColourBlock( a, b, remapped, block );
+}
+
+void WriteColourBlock4( Vec3::Arg start, Vec3::Arg end, u8 const* indices, void* block )
+{
+    // get the packed values
+    int a = FloatTo565( start );
+    int b = FloatTo565( end );
+
+    // remap the indices
+    u8 remapped[16];
+    if( a < b )
+    {
+        // swap a and b
+        std::swap( a, b );
+        for( int i = 0; i < 16; ++i )
+            remapped[i] = ( indices[i] ^ 0x1 ) & 0x3;
+    }
+    else if( a == b )
+    {
+        // use index 0
+        for( int i = 0; i < 16; ++i )
+            remapped[i] = 0;
+    }
+    else
+    {
+        // use the indices directly
+        for( int i = 0; i < 16; ++i )
+            remapped[i] = indices[i];
+    }
+
+    // write the block
+    WriteColourBlock( a, b, remapped, block );
+}
+
+static int Unpack565( u8 const* packed, u8* colour )
+{
+    // build the packed value
+    int value = ( int )packed[0] | ( ( int )packed[1] << 8 );
+
+    // get the components in the stored range
+    u8 red = ( u8 )( ( value >> 11 ) & 0x1f );
+    u8 green = ( u8 )( ( value >> 5 ) & 0x3f );
+    u8 blue = ( u8 )( value & 0x1f );
+
+    // scale up to 8 bits
+    colour[0] = ( red << 3 ) | ( red >> 2 );
+    colour[1] = ( green << 2 ) | ( green >> 4 );
+    colour[2] = ( blue << 3 ) | ( blue >> 2 );
+    colour[3] = 255;
+
+    // return the value
+    return value;
+}
+
+void DecompressColour( u8* rgba, void const* block, bool isDxt1 )
+{
+    // get the block bytes
+    u8 const* bytes = reinterpret_cast< u8 const* >( block );
+
+    // unpack the endpoints
+    u8 codes[16];
+    int a = Unpack565( bytes, codes );
+    int b = Unpack565( bytes + 2, codes + 4 );
+
+    // generate the midpoints
+    for( int i = 0; i < 3; ++i )
+    {
+        int c = codes[i];
+        int d = codes[4 + i];
+
+        if( isDxt1 && a <= b )
+        {
+            codes[8 + i] = ( u8 )( ( c + d )/2 );
+            codes[12 + i] = 0;
+        }
+        else
+        {
+            codes[8 + i] = ( u8 )( ( 2*c + d )/3 );
+            codes[12 + i] = ( u8 )( ( c + 2*d )/3 );
+        }
+    }
+
+    // fill in alpha for the intermediate values
+    codes[8 + 3] = 255;
+    codes[12 + 3] = ( isDxt1 && a <= b ) ? 0 : 255;
+
+    // unpack the indices
+    u8 indices[16];
+    for( int i = 0; i < 4; ++i )
+    {
+        u8* ind = indices + 4*i;
+        u8 packed = bytes[4 + i];
+
+        ind[0] = packed & 0x3;
+        ind[1] = ( packed >> 2 ) & 0x3;
+        ind[2] = ( packed >> 4 ) & 0x3;
+        ind[3] = ( packed >> 6 ) & 0x3;
+    }
+
+    // store out the colours
+    for( int i = 0; i < 16; ++i )
+    {
+        u8 offset = 4*indices[i];
+        for( int j = 0; j < 4; ++j )
+            rgba[4*i + j] = codes[offset + j];
+    }
+}
+
+} // namespace squish