1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
/* 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "sound/softsynth/pcspk.h"
namespace Audio {
const PCSpeaker::generatorFunc PCSpeaker::generateWave[] =
{&PCSpeaker::generateSquare, &PCSpeaker::generateSine,
&PCSpeaker::generateSaw, &PCSpeaker::generateTriangle};
PCSpeaker::PCSpeaker(int rate) {
_rate = rate;
_wave = kWaveFormSquare;
_playForever = false;
_oscLength = 0;
_oscSamples = 0;
_remainingSamples = 0;
_mixedSamples = 0;
_volume = 255;
}
PCSpeaker::~PCSpeaker() {
}
void PCSpeaker::play(WaveForm wave, int freq, int32 length) {
Common::StackLock lock(_mutex);
assert((wave >= kWaveFormSquare) && (wave <= kWaveFormTriangle));
_wave = wave;
_oscLength = _rate / freq;
_oscSamples = 0;
if (length == -1) {
_remainingSamples = 1;
_playForever = true;
} else {
_remainingSamples = (_rate * length) / 1000;
_playForever = false;
}
_mixedSamples = 0;
}
void PCSpeaker::stop(int32 delay) {
Common::StackLock lock(_mutex);
_remainingSamples = (_rate * delay) / 1000;
_playForever = false;
}
void PCSpeaker::setVolume(byte volume) {
_volume = volume;
}
bool PCSpeaker::isPlaying() const {
return _remainingSamples != 0;
}
int PCSpeaker::readBuffer(int16 *buffer, const int numSamples) {
Common::StackLock lock(_mutex);
int i;
for (i = 0; _remainingSamples && (i < numSamples); i++) {
buffer[i] = generateWave[_wave](_oscSamples, _oscLength) * _volume;
if (_oscSamples++ >= _oscLength)
_oscSamples = 0;
if (!_playForever)
_remainingSamples--;
_mixedSamples++;
}
// Clear the rest of the buffer
if (i < numSamples)
memset(buffer + i, 0, (numSamples - i) * sizeof(int16));
return numSamples;
}
int8 PCSpeaker::generateSquare(uint32 x, uint32 oscLength) {
return (x < (oscLength / 2)) ? 127 : -128;
}
int8 PCSpeaker::generateSine(uint32 x, uint32 oscLength) {
if (oscLength == 0)
return 0;
// TODO: Maybe using a look-up-table would be better?
return CLIP<int16>((int16) (128 * sin(2.0 * PI * x / oscLength)), -128, 127);
}
int8 PCSpeaker::generateSaw(uint32 x, uint32 oscLength) {
if (oscLength == 0)
return 0;
return ((x * (65536 / oscLength)) >> 8) - 128;
}
int8 PCSpeaker::generateTriangle(uint32 x, uint32 oscLength) {
if (oscLength == 0)
return 0;
int y = ((x * (65536 / (oscLength / 2))) >> 8) - 128;
return (x <= (oscLength / 2)) ? y : (256 - y);
}
} // End of namespace Audio
|
