2 * Adplug - Replayer for many OPL2/OPL3 audio file formats.
3 * Copyright (C) 1999 - 2010 Simon Peter, <dn.tlp@gmx.net>, et al.
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 * surroundopl.h - Wrapper class to provide a surround/harmonic effect
20 * for another OPL emulator, by Adam Nielsen <malvineous@shikadi.net>
22 * Stereo harmonic algorithm by Adam Nielsen <malvineous@shikadi.net>
23 * Please give credit if you use this algorithm elsewhere :-)
26 #ifndef H_ADPLUG_SURROUNDOPL
27 #define H_ADPLUG_SURROUNDOPL
29 #include <stdint.h> // for uintxx_t
32 // The right-channel is increased in frequency by itself divided by this amount.
33 // The right value should not noticeably change the pitch, but it should provide
34 // a nice stereo harmonic effect.
35 #define FREQ_OFFSET 128.0//96.0
37 // Number of FNums away from the upper/lower limit before switching to the next
38 // block (octave.) By rights it should be zero, but for some reason this seems
39 // to cut it to close and the transposed OPL doesn't hit the right note all the
40 // time. Setting it higher means it will switch blocks sooner and that seems
41 // to help. Don't set it too high or it'll get stuck in an infinite loop if
42 // one block is too high and the adjacent block is too low ;-)
43 #define NEWBLOCK_LIMIT 32
45 class CSurroundopl: public Copl
53 uint8_t iTweakedFMReg[256];
54 uint8_t iCurrentTweakedBlock[9]; // Current value of the Block in the tweaked OPL chip
55 uint8_t iCurrentFNum[9]; // Current value of the FNum in the tweaked OPL chip
59 CSurroundopl(Copl *a, Copl *b, bool use16bit);
62 void update(short *buf, int samples);
63 void write(int reg, int val);