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
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
#include <sys/ioctl.h>
#include <stdint.h>
#include <fcntl.h>
#include <unistd.h>
#include <alsa/asoundlib.h>
#include "sound_output.h"
static snd_pcm_t *handle;
uint32_t Audio_Init()
{
snd_pcm_hw_params_t *params;
uint32_t val;
int32_t dir = -1;
snd_pcm_uframes_t frames;
/* Open PCM device for playback. */
int32_t rc = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
if (rc < 0)
rc = snd_pcm_open(&handle, "plughw:0,0,0", SND_PCM_STREAM_PLAYBACK, 0);
if (rc < 0)
rc = snd_pcm_open(&handle, "plughw:0,0", SND_PCM_STREAM_PLAYBACK, 0);
if (rc < 0)
rc = snd_pcm_open(&handle, "plughw:1,0,0", SND_PCM_STREAM_PLAYBACK, 0);
if (rc < 0)
rc = snd_pcm_open(&handle, "plughw:1,0", SND_PCM_STREAM_PLAYBACK, 0);
if (rc < 0)
{
fprintf(stderr, "unable to open PCM device: %s\n", snd_strerror(rc));
return 1;
}
/* Allocate a hardware parameters object. */
snd_pcm_hw_params_alloca(¶ms);
/* Fill it in with default values. */
rc = snd_pcm_hw_params_any(handle, params);
if (rc < 0)
{
fprintf(stderr, "Error:snd_pcm_hw_params_any %s\n", snd_strerror(rc));
return 1;
}
/* Set the desired hardware parameters. */
/* Interleaved mode */
rc = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
if (rc < 0)
{
fprintf(stderr, "Error:snd_pcm_hw_params_set_access %s\n", snd_strerror(rc));
return 1;
}
/* Signed 16-bit little-endian format */
rc = snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
if (rc < 0)
{
fprintf(stderr, "Error:snd_pcm_hw_params_set_format %s\n", snd_strerror(rc));
return 1;
}
/* Two channels (stereo) */
rc = snd_pcm_hw_params_set_channels(handle, params, 2);
if (rc < 0)
{
fprintf(stderr, "Error:snd_pcm_hw_params_set_channels %s\n", snd_strerror(rc));
return 1;
}
val = SOUND_OUTPUT_FREQUENCY;
rc = snd_pcm_hw_params_set_rate_near(handle, params, &val, &dir);
if (rc < 0)
{
fprintf(stderr, "Error:snd_pcm_hw_params_set_rate_near %s\n", snd_strerror(rc));
return 1;
}
/* Set period size to settings.aica.BufferSize frames. */
frames = SOUND_SAMPLES_SIZE;
rc = snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir);
if (rc < 0)
{
fprintf(stderr, "Error:snd_pcm_hw_params_set_buffer_size_near %s\n", snd_strerror(rc));
return 1;
}
frames *= 4;
rc = snd_pcm_hw_params_set_buffer_size_near(handle, params, &frames);
if (rc < 0)
{
fprintf(stderr, "Error:snd_pcm_hw_params_set_buffer_size_near %s\n", snd_strerror(rc));
return 1;
}
/* Write the parameters to the driver */
rc = snd_pcm_hw_params(handle, params);
if (rc < 0)
{
fprintf(stderr, "Unable to set hw parameters: %s\n", snd_strerror(rc));
return 1;
}
return 0;
}
void Audio_Write(int16_t* restrict buffer, uint32_t buffer_size)
{
uint32_t i;
long ret, len;
if (!handle) return;
len = buffer_size;
ret = snd_pcm_writei(handle, buffer, len);
while(ret != len)
{
if (ret < 0)
{
snd_pcm_prepare( handle );
}
else
{
len -= ret;
}
ret = snd_pcm_writei(handle, buffer, len);
}
}
bool Audio_Underrun_Likely() {
return false;
}
void Audio_Close()
{
if (handle)
{
snd_pcm_drain(handle);
snd_pcm_close(handle);
}
}
|
