1
2 /*
3 * REminiscence - Flashback interpreter
4 * Copyright (C) 2005-2019 Gregory Montoir (cyx@users.sourceforge.net)
5 */
6
7 #include "mixer.h"
8 #include "sfx_player.h"
9 #include "util.h"
10
11 // volume instruments are either equal to 64 or 32 (this corresponds to aud0vol)
12 // use one third of the volume for master (for comparison, modplug uses a master volume of 128, max 512)
13 static const int kMasterVolume = 64 * 3;
14
15 // 12 dB/oct Butterworth low-pass filter at 3.3 kHz
16 static const bool kLowPassFilter = true;
17
18 #define NZEROS 2
19 #define NPOLES 2
20 static float bw_xf[NZEROS+1], bw_yf[NPOLES+1];
21 static const float GAIN = 7.655158005e+00;
22
butterworth(int16_t * p,int len)23 static void butterworth(int16_t *p, int len) {
24 for (int i = 0; i < len; ++i) {
25 bw_xf[0] = bw_xf[1]; bw_xf[1] = bw_xf[2];
26 bw_xf[2] = p[i] / GAIN;
27 bw_yf[0] = bw_yf[1]; bw_yf[1] = bw_yf[2];
28 bw_yf[2] = (bw_xf[0] + bw_xf[2]) + 2 * bw_xf[1] + (-0.2729352339 * bw_yf[0]) + (0.7504117278 * bw_yf[1]);
29 p[i] = (int16_t)CLIP(bw_yf[2], -32768.f, 32767.f);
30 }
31 }
32
SfxPlayer(Mixer * mixer)33 SfxPlayer::SfxPlayer(Mixer *mixer)
34 : _mod(0), _playing(false), _mix(mixer) {
35 }
36
play(uint8_t num)37 void SfxPlayer::play(uint8_t num) {
38 debug(DBG_SFX, "SfxPlayer::play(%d)", num);
39 if (!_playing) {
40 assert(num >= 68 && num <= 75);
41 static const Module *modTable[] = {
42 &_module68, &_module68, &_module70, &_module70,
43 &_module72, &_module73, &_module74, &_module75
44 };
45 _mod = modTable[num - 68];
46 _curOrder = 0;
47 _numOrders = READ_BE_UINT16(_mod->moduleData);
48 _orderDelay = 0;
49 _modData = _mod->moduleData + 0x22;
50 memset(_samples, 0, sizeof(_samples));
51 _samplesLeft = 0;
52 _mix->setPremixHook(mixCallback, this);
53 _playing = true;
54 if (kLowPassFilter) {
55 memset(bw_xf, 0, sizeof(bw_xf));
56 memset(bw_yf, 0, sizeof(bw_yf));
57 }
58 }
59 }
60
stop()61 void SfxPlayer::stop() {
62 if (_playing) {
63 _mix->setPremixHook(0, 0);
64 _playing = false;
65 }
66 }
67
playSample(int channel,const uint8_t * sampleData,uint16_t period)68 void SfxPlayer::playSample(int channel, const uint8_t *sampleData, uint16_t period) {
69 assert(channel < NUM_CHANNELS);
70 SampleInfo *si = &_samples[channel];
71 si->len = READ_BE_UINT16(sampleData); sampleData += 2;
72 si->vol = READ_BE_UINT16(sampleData); sampleData += 2;
73 si->loopPos = READ_BE_UINT16(sampleData); sampleData += 2;
74 si->loopLen = READ_BE_UINT16(sampleData); sampleData += 2;
75 si->freq = PAULA_FREQ / period;
76 si->pos = 0;
77 si->data = sampleData;
78 }
79
handleTick()80 void SfxPlayer::handleTick() {
81 if (!_playing) {
82 return;
83 }
84 if (_orderDelay != 0) {
85 --_orderDelay;
86 // check for end of song
87 if (_orderDelay == 0 && _modData == 0) {
88 _playing = false;
89 }
90 } else {
91 _orderDelay = READ_BE_UINT16(_mod->moduleData + 2);
92 debug(DBG_SFX, "curOrder=%d/%d _orderDelay=%d\n", _curOrder, _numOrders, _orderDelay);
93 int16_t period = 0;
94 for (int ch = 0; ch < 3; ++ch) {
95 const uint8_t *sampleData = 0;
96 uint8_t b = *_modData++;
97 if (b != 0) {
98 --b;
99 assert(b < 5);
100 period = READ_BE_UINT16(_mod->moduleData + 4 + b * 2);
101 sampleData = _mod->sampleData[b];
102 }
103 b = *_modData++;
104 if (b != 0) {
105 int16_t per = period + (b - 1);
106 if (per >= 0 && per < 40) {
107 per = _periodTable[per];
108 } else if (per == -3) {
109 per = 0xA0;
110 } else {
111 per = 0x71;
112 }
113 playSample(ch, sampleData, per);
114 }
115 }
116 ++_curOrder;
117 if (_curOrder >= _numOrders) {
118 debug(DBG_SFX, "End of song");
119 _orderDelay += 20;
120 _modData = 0;
121 }
122 }
123 }
124
mixSamples(int16_t * buf,int samplesLen)125 void SfxPlayer::mixSamples(int16_t *buf, int samplesLen) {
126 for (int i = 0; i < NUM_CHANNELS; ++i) {
127 SampleInfo *si = &_samples[i];
128 if (si->data) {
129 int16_t *mixbuf = buf;
130 int len = si->len << FRAC_BITS;
131 int loopLen = si->loopLen << FRAC_BITS;
132 int loopPos = si->loopPos << FRAC_BITS;
133 int deltaPos = (si->freq << FRAC_BITS) / _mix->getSampleRate();
134 int curLen = samplesLen;
135 int pos = si->pos;
136 while (curLen != 0) {
137 int count;
138 if (loopLen > (2 << FRAC_BITS)) {
139 assert(si->loopPos + si->loopLen <= si->len);
140 if (pos >= loopPos + loopLen) {
141 pos -= loopLen;
142 }
143 count = MIN(curLen, (loopPos + loopLen - pos - 1) / deltaPos + 1);
144 curLen -= count;
145 } else {
146 if (pos >= len) {
147 count = 0;
148 } else {
149 count = MIN(curLen, (len - pos - 1) / deltaPos + 1);
150 }
151 curLen = 0;
152 }
153 while (count--) {
154 const int out = si->getPCM(pos >> FRAC_BITS) * si->vol / kMasterVolume;
155 *mixbuf = ADDC_S16(*mixbuf, S8_to_S16(out));
156 ++mixbuf;
157 pos += deltaPos;
158 }
159 }
160 si->pos = pos;
161 }
162 }
163 }
164
mix(int16_t * buf,int len)165 bool SfxPlayer::mix(int16_t *buf, int len) {
166 memset(buf, 0, sizeof(int16_t) * len);
167 if (_playing) {
168 const int samplesPerTick = _mix->getSampleRate() / 50;
169 while (len != 0) {
170 if (_samplesLeft == 0) {
171 handleTick();
172 _samplesLeft = samplesPerTick;
173 }
174 int count = _samplesLeft;
175 if (count > len) {
176 count = len;
177 }
178 _samplesLeft -= count;
179 len -= count;
180 mixSamples(buf, count);
181 if (kLowPassFilter) {
182 butterworth(buf, count);
183 }
184 buf += count;
185 }
186 }
187 return _playing;
188 }
189
mixCallback(void * param,int16_t * samples,int len)190 bool SfxPlayer::mixCallback(void *param, int16_t *samples, int len) {
191 return ((SfxPlayer *)param)->mix(samples, len);
192 }
193