1 /*
2 * AdPlug - Replayer for many OPL2/OPL3 audio file formats.
3 * Copyright (C) 1999 - 2005 Simon Peter <dn.tlp@gmx.net>, et al.
4 *
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.
9 *
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.
14 *
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * emuopl.cpp - Emulated OPL, by Simon Peter <dn.tlp@gmx.net>
20 */
21
22 #include "emuopl.h"
23
CEmuopl(int rate,bool bit16,bool usestereo)24 CEmuopl::CEmuopl(int rate, bool bit16, bool usestereo)
25 : use16bit(bit16), stereo(usestereo), mixbufSamples(0)
26 {
27 opl[0] = OPLCreate(OPL_TYPE_YM3812, 3579545, rate);
28 opl[1] = OPLCreate(OPL_TYPE_YM3812, 3579545, rate);
29
30 currType = TYPE_DUAL_OPL2;
31
32 init();
33 }
34
~CEmuopl()35 CEmuopl::~CEmuopl()
36 {
37 OPLDestroy(opl[0]); OPLDestroy(opl[1]);
38
39 if(mixbufSamples) {
40 delete [] mixbuf0;
41 delete [] mixbuf1;
42 delete [] mixbuf2;
43 }
44 }
45
update(short * buf,int samples)46 void CEmuopl::update(short *buf, int samples)
47 {
48 int i;
49
50 //ensure that our mix buffers are adequately sized
51 if(mixbufSamples < samples) {
52 if(mixbufSamples) { delete[] mixbuf0; delete[] mixbuf1; delete[] mixbuf2; }
53 mixbufSamples = samples;
54
55 //*2 = make room for stereo, if we need it
56 mixbuf0 = new short[samples*2];
57 mixbuf1 = new short[samples*2];
58 mixbuf2 = new short[samples*2];
59 }
60
61 //data should be rendered to outbuf
62 //tempbuf should be used as a temporary buffer
63 //if we are supposed to generate 16bit output,
64 //then outbuf may point directly to the actual waveform output "buf"
65 //if we are supposed to generate 8bit output,
66 //then outbuf cannot point to "buf" (because there will not be enough room)
67 //and so it must point to a mixbuf instead--
68 //it will be reduced to 8bit and put in "buf" later
69 short *outbuf;
70 short *tempbuf=mixbuf0;
71 short *tempbuf2=mixbuf1;
72 if(use16bit) outbuf = buf;
73 else outbuf = mixbuf2;
74
75 //all of the following rendering code produces 16bit output
76
77 switch(currType) {
78 case TYPE_OPL2:
79 //for opl2 mode:
80 //render chip0 to the output buffer
81 YM3812UpdateOne(opl[0],outbuf,samples);
82
83 //if we are supposed to output stereo,
84 //then we need to dup the mono channel
85 if(stereo)
86 for(i=samples-1;i>=0;i--) {
87 outbuf[i*2] = outbuf[i];
88 outbuf[i*2+1] = outbuf[i];
89 }
90 break;
91
92 case TYPE_OPL3: // unsupported
93 break;
94
95 case TYPE_DUAL_OPL2:
96 //for dual opl2 mode:
97 //render each chip to a different tempbuffer
98 YM3812UpdateOne(opl[0],tempbuf2,samples);
99 YM3812UpdateOne(opl[1],tempbuf,samples);
100
101 //output stereo:
102 //then we need to interleave the two buffers
103 if(stereo){
104 //first, spread tempbuf's samples across left channel
105 //left channel
106 for(i=0;i<samples;i++)
107 outbuf[i*2] = tempbuf2[i];
108 //next, insert the samples from tempbuf2 into right channel
109 for(i=0;i<samples;i++)
110 outbuf[i*2+1] = tempbuf[i];
111 } else
112 //output mono:
113 //then we need to mix the two buffers into buf
114 for(i=0;i<samples;i++)
115 outbuf[i] = (tempbuf[i]>>1) + (tempbuf2[i]>>1);
116 break;
117 }
118
119 //now reduce to 8bit if we need to
120 if(!use16bit)
121 for(i=0;i<(stereo ? samples*2 : samples);i++)
122 ((char *)buf)[i] = (outbuf[i] >> 8) ^ 0x80;
123 }
124
write(int reg,int val)125 void CEmuopl::write(int reg, int val)
126 {
127 switch(currType){
128 case TYPE_OPL2:
129 case TYPE_DUAL_OPL2:
130 OPLWrite(opl[currChip], 0, reg);
131 OPLWrite(opl[currChip], 1, val);
132 break;
133 case TYPE_OPL3: // unsupported
134 break;
135 }
136 }
137
init()138 void CEmuopl::init()
139 {
140 OPLResetChip(opl[0]); OPLResetChip(opl[1]);
141 currChip = 0;
142 }
143
settype(ChipType type)144 void CEmuopl::settype(ChipType type)
145 {
146 currType = type;
147 }
148