scummvm/graphics/palette.cpp

98 lines
2.7 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "graphics/palette.h"
namespace Graphics {
PaletteLookup::PaletteLookup() {
_paletteSize = 0;
}
PaletteLookup::PaletteLookup(const byte *palette, uint len) {
_paletteSize = len;
memcpy(_palette, palette, len * 3);
}
bool PaletteLookup::setPalette(const byte *palette, uint len) {
// Check if the passed palette matched the one we have
if (len == _paletteSize && !memcmp(_palette, palette, len * 3))
return false;
_paletteSize = len;
memcpy(_palette, palette, len * 3);
_colorHash.clear();
return true;
}
byte PaletteLookup::findBestColor(byte cr, byte cg, byte cb, bool useNaiveAlg) {
if (_paletteSize == 0) {
warning("PaletteLookup::findBestColor(): Palette was not set");
return 0;
}
uint bestColor = 0;
double min = 0xFFFFFFFF;
uint32 color = cr << 16 | cg << 8 | cb;
if (_colorHash.contains(color))
return _colorHash[color];
if (useNaiveAlg) {
byte *palettePtr = _palette;
for (uint i = 0; i < _paletteSize; i++) {
int redSquareDiff = (cr - palettePtr[0]) * (cr - palettePtr[0]);
int greenSquareDiff = (cg - palettePtr[1]) * (cg - palettePtr[1]);
int blueSquareDiff = (cb - palettePtr[2]) * (cb - palettePtr[2]);
int weightedColorError = 3 * redSquareDiff + 5 * greenSquareDiff + 2 * blueSquareDiff;
if (weightedColorError < min) {
bestColor = i;
min = weightedColorError;
}
palettePtr += 3;
}
} else {
for (uint i = 0; i < _paletteSize; ++i) {
int rmean = (*(_palette + 3 * i + 0) + cr) / 2;
int r = *(_palette + 3 * i + 0) - cr;
int g = *(_palette + 3 * i + 1) - cg;
int b = *(_palette + 3 * i + 2) - cb;
double dist = sqrt((((512 + rmean) * r * r) >> 8) + 4 * g * g + (((767 - rmean) * b * b) >> 8));
if (min > dist) {
bestColor = i;
min = dist;
}
}
}
_colorHash[color] = bestColor;
return bestColor;
}
} // end of namespace Graphics