palette_utils.h

/* 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/>.
 *
 */
 
#ifndef HARVESTER_PALETTE_UTILS_H
#define HARVESTER_PALETTE_UTILS_H
 
#include "common/scummsys.h"
 
namespace Harvester {
 
inline byte expandHarvesterVgaDacColor(byte value) {
    // Match VGA/DOSBox-X DAC expansion: replicate the high 2 bits into the low 2 bits.
    return (value << 2) | (value >> 4);
}
 
inline void buildHarvesterDisplayPalette(const byte *source, float brightness, byte *dest) {
    memset(dest, 0, 256 * 3);
    if (!source)
        return;
 
    if (brightness < 0.0f)
        brightness = 0.0f;
 
    for (uint color = 1; color < 256; ++color) {
        for (uint channel = 0; channel < 3; ++channel) {
            const uint index = color * 3 + channel;
            const int vgaDacValue = source[index] >> 2;
            int scaled = (int)(vgaDacValue * brightness + 0.5f);
            if (scaled > 63)
                scaled = 63;
            dest[index] = expandHarvesterVgaDacColor((byte)scaled);
        }
    }
}
 
} // End of namespace Harvester
 
#endif // HARVESTER_PALETTE_UTILS_H