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/*
* Adplug - Replayer for many OPL2/OPL3 audio file formats.
* Copyright (C) 1999 - 2010 Simon Peter, <dn.tlp@gmx.net>, et al.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* surroundopl.h - Wrapper class to provide a surround/harmonic effect
* for another OPL emulator, by Adam Nielsen <malvineous@shikadi.net>
*
* Stereo harmonic algorithm by Adam Nielsen <malvineous@shikadi.net>
* Please give credit if you use this algorithm elsewhere :-)
*/
#ifndef H_ADPLUG_SURROUNDOPL
#define H_ADPLUG_SURROUNDOPL
#include <stdint.h> // for uintxx_t
#include "opl.h"
// The right-channel is increased in frequency by itself divided by this amount.
// The right value should not noticeably change the pitch, but it should provide
// a nice stereo harmonic effect.
#define FREQ_OFFSET 128.0//96.0
// Number of FNums away from the upper/lower limit before switching to the next
// block (octave.) By rights it should be zero, but for some reason this seems
// to cut it to close and the transposed OPL doesn't hit the right note all the
// time. Setting it higher means it will switch blocks sooner and that seems
// to help. Don't set it too high or it'll get stuck in an infinite loop if
// one block is too high and the adjacent block is too low ;-)
#define NEWBLOCK_LIMIT 32
class CSurroundopl: public Copl
{
private:
bool use16bit;
short bufsize;
short *lbuf, *rbuf;
Copl *a, *b;
uint8_t iFMReg[256];
uint8_t iTweakedFMReg[256];
uint8_t iCurrentTweakedBlock[9]; // Current value of the Block in the tweaked OPL chip
uint8_t iCurrentFNum[9]; // Current value of the FNum in the tweaked OPL chip
public:
CSurroundopl(Copl *a, Copl *b, bool use16bit);
~CSurroundopl();
void update(short *buf, int samples);
void write(int reg, int val);
void init();
};
#endif
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