247 lines
6.5 KiB
C++
247 lines
6.5 KiB
C++
/* -----------------------------------------------------------------------------
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Copyright (c) 2006 Simon Brown si@sjbrown.co.uk
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be included
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in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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-------------------------------------------------------------------------- */
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#include "colourblock.h"
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// -- GODOT start --
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#include "alpha.h"
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// -- GODOT end --
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namespace squish {
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static int FloatToInt( float a, int limit )
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{
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// use ANSI round-to-zero behaviour to get round-to-nearest
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int i = ( int )( a + 0.5f );
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// clamp to the limit
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if( i < 0 )
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i = 0;
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else if( i > limit )
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i = limit;
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// done
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return i;
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}
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static int FloatTo565( Vec3::Arg colour )
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{
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// get the components in the correct range
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int r = FloatToInt( 31.0f*colour.X(), 31 );
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int g = FloatToInt( 63.0f*colour.Y(), 63 );
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int b = FloatToInt( 31.0f*colour.Z(), 31 );
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// pack into a single value
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return ( r << 11 ) | ( g << 5 ) | b;
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}
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static void WriteColourBlock( int a, int b, u8* indices, void* block )
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{
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// get the block as bytes
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u8* bytes = ( u8* )block;
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// write the endpoints
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bytes[0] = ( u8 )( a & 0xff );
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bytes[1] = ( u8 )( a >> 8 );
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bytes[2] = ( u8 )( b & 0xff );
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bytes[3] = ( u8 )( b >> 8 );
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// write the indices
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for( int i = 0; i < 4; ++i )
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{
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u8 const* ind = indices + 4*i;
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bytes[4 + i] = ind[0] | ( ind[1] << 2 ) | ( ind[2] << 4 ) | ( ind[3] << 6 );
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}
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}
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void WriteColourBlock3( Vec3::Arg start, Vec3::Arg end, u8 const* indices, void* block )
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{
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// get the packed values
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int a = FloatTo565( start );
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int b = FloatTo565( end );
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// remap the indices
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u8 remapped[16];
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if( a <= b )
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{
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// use the indices directly
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for( int i = 0; i < 16; ++i )
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remapped[i] = indices[i];
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}
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else
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{
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// swap a and b
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std::swap( a, b );
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for( int i = 0; i < 16; ++i )
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{
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if( indices[i] == 0 )
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remapped[i] = 1;
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else if( indices[i] == 1 )
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remapped[i] = 0;
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else
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remapped[i] = indices[i];
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}
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}
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// write the block
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WriteColourBlock( a, b, remapped, block );
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}
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void WriteColourBlock4( Vec3::Arg start, Vec3::Arg end, u8 const* indices, void* block )
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{
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// get the packed values
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int a = FloatTo565( start );
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int b = FloatTo565( end );
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// remap the indices
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u8 remapped[16];
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if( a < b )
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{
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// swap a and b
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std::swap( a, b );
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for( int i = 0; i < 16; ++i )
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remapped[i] = ( indices[i] ^ 0x1 ) & 0x3;
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}
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else if( a == b )
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{
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// use index 0
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for( int i = 0; i < 16; ++i )
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remapped[i] = 0;
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}
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else
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{
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// use the indices directly
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for( int i = 0; i < 16; ++i )
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remapped[i] = indices[i];
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}
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// write the block
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WriteColourBlock( a, b, remapped, block );
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}
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static int Unpack565( u8 const* packed, u8* colour )
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{
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// build the packed value
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int value = ( int )packed[0] | ( ( int )packed[1] << 8 );
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// get the components in the stored range
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u8 red = ( u8 )( ( value >> 11 ) & 0x1f );
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u8 green = ( u8 )( ( value >> 5 ) & 0x3f );
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u8 blue = ( u8 )( value & 0x1f );
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// scale up to 8 bits
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colour[0] = ( red << 3 ) | ( red >> 2 );
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colour[1] = ( green << 2 ) | ( green >> 4 );
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colour[2] = ( blue << 3 ) | ( blue >> 2 );
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colour[3] = 255;
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// return the value
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return value;
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}
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void DecompressColour( u8* rgba, void const* block, bool isDxt1 )
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{
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// get the block bytes
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u8 const* bytes = reinterpret_cast< u8 const* >( block );
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// unpack the endpoints
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u8 codes[16];
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int a = Unpack565( bytes, codes );
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int b = Unpack565( bytes + 2, codes + 4 );
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// generate the midpoints
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for( int i = 0; i < 3; ++i )
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{
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int c = codes[i];
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int d = codes[4 + i];
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if( isDxt1 && a <= b )
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{
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codes[8 + i] = ( u8 )( ( c + d )/2 );
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codes[12 + i] = 0;
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}
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else
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{
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codes[8 + i] = ( u8 )( ( 2*c + d )/3 );
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codes[12 + i] = ( u8 )( ( c + 2*d )/3 );
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}
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}
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// fill in alpha for the intermediate values
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codes[8 + 3] = 255;
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codes[12 + 3] = ( isDxt1 && a <= b ) ? 0 : 255;
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// unpack the indices
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u8 indices[16];
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for( int i = 0; i < 4; ++i )
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{
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u8* ind = indices + 4*i;
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u8 packed = bytes[4 + i];
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ind[0] = packed & 0x3;
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ind[1] = ( packed >> 2 ) & 0x3;
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ind[2] = ( packed >> 4 ) & 0x3;
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ind[3] = ( packed >> 6 ) & 0x3;
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}
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// store out the colours
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for( int i = 0; i < 16; ++i )
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{
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u8 offset = 4*indices[i];
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for( int j = 0; j < 4; ++j )
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rgba[4*i + j] = codes[offset + j];
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}
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}
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// -- GODOT start --
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void DecompressColourBc4( u8* rgba, void const* block)
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{
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DecompressAlphaDxt5(rgba,block);
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for ( int i = 0; i < 16; ++i ) {
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rgba[i*4] = rgba[i*4 + 3];
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rgba[i*4 + 1] = 0;
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rgba[i*4 + 2] = 0;
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rgba[i*4 + 3] = 255;
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}
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}
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void DecompressColourBc5( u8* rgba, void const* block)
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{
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void const* rblock = block;
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void const* gblock = reinterpret_cast< u8 const* >( block ) + 8;
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DecompressAlphaDxt5(rgba,rblock);
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for ( int i = 0; i < 16; ++i ) {
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rgba[i*4] = rgba[i*4 + 3];
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}
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DecompressAlphaDxt5(rgba,gblock);
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for ( int i = 0; i < 16; ++i ) {
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rgba[i*4+1] = rgba[i*4 + 3];
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rgba[i*4 + 2] = 0;
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rgba[i*4 + 3] = 255;
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}
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}
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// -- GODOT end --
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} // namespace squish
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