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initial forking of open-al to create multiple listeners
author Robert McIntyre <rlm@mit.edu>
date Tue, 25 Oct 2011 13:02:31 -0700
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-1:000000000000 0:f9476ff7637e
1 /**
2 * OpenAL cross platform audio library
3 * Copyright (C) 2010 by Chris Robinson
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
18 * Or go to http://www.gnu.org/copyleft/lgpl.html
19 */
20
21 #include "config.h"
22
23 #include <stdlib.h>
24 #include "alMain.h"
25 #include "AL/al.h"
26 #include "AL/alc.h"
27
28
29 typedef struct {
30 volatile int killNow;
31 ALvoid *thread;
32 } null_data;
33
34
35 static const ALCchar nullDevice[] = "No Output";
36
37 static ALuint NullProc(ALvoid *ptr)
38 {
39 ALCdevice *Device = (ALCdevice*)ptr;
40 null_data *data = (null_data*)Device->ExtraData;
41 ALuint now, start;
42 ALuint64 avail, done;
43 const ALuint restTime = (ALuint64)Device->UpdateSize * 1000 /
44 Device->Frequency / 2;
45
46 done = 0;
47 start = timeGetTime();
48 while(!data->killNow && Device->Connected)
49 {
50 now = timeGetTime();
51
52 avail = (ALuint64)(now-start) * Device->Frequency / 1000;
53 if(avail < done)
54 {
55 /* Timer wrapped. Add the remainder of the cycle to the available
56 * count and reset the number of samples done */
57 avail += (ALuint64)0xFFFFFFFFu*Device->Frequency/1000 - done;
58 done = 0;
59 }
60 if(avail-done < Device->UpdateSize)
61 {
62 Sleep(restTime);
63 continue;
64 }
65
66 while(avail-done >= Device->UpdateSize)
67 {
68 aluMixData(Device, NULL, Device->UpdateSize);
69 done += Device->UpdateSize;
70 }
71 }
72
73 return 0;
74 }
75
76 static ALCboolean null_open_playback(ALCdevice *device, const ALCchar *deviceName)
77 {
78 null_data *data;
79
80 if(!deviceName)
81 deviceName = nullDevice;
82 else if(strcmp(deviceName, nullDevice) != 0)
83 return ALC_FALSE;
84
85 data = (null_data*)calloc(1, sizeof(*data));
86
87 device->szDeviceName = strdup(deviceName);
88 device->ExtraData = data;
89 return ALC_TRUE;
90 }
91
92 static void null_close_playback(ALCdevice *device)
93 {
94 null_data *data = (null_data*)device->ExtraData;
95
96 free(data);
97 device->ExtraData = NULL;
98 }
99
100 static ALCboolean null_reset_playback(ALCdevice *device)
101 {
102 null_data *data = (null_data*)device->ExtraData;
103
104 SetDefaultWFXChannelOrder(device);
105
106 data->thread = StartThread(NullProc, device);
107 if(data->thread == NULL)
108 return ALC_FALSE;
109
110 return ALC_TRUE;
111 }
112
113 static void null_stop_playback(ALCdevice *device)
114 {
115 null_data *data = (null_data*)device->ExtraData;
116
117 if(!data->thread)
118 return;
119
120 data->killNow = 1;
121 StopThread(data->thread);
122 data->thread = NULL;
123
124 data->killNow = 0;
125 }
126
127
128 static const BackendFuncs null_funcs = {
129 null_open_playback,
130 null_close_playback,
131 null_reset_playback,
132 null_stop_playback,
133 NULL,
134 NULL,
135 NULL,
136 NULL,
137 NULL,
138 NULL
139 };
140
141 ALCboolean alc_null_init(BackendFuncs *func_list)
142 {
143 *func_list = null_funcs;
144 return ALC_TRUE;
145 }
146
147 void alc_null_deinit(void)
148 {
149 }
150
151 void alc_null_probe(enum DevProbe type)
152 {
153 switch(type)
154 {
155 case DEVICE_PROBE:
156 AppendDeviceList(nullDevice);
157 break;
158 case ALL_DEVICE_PROBE:
159 AppendAllDeviceList(nullDevice);
160 break;
161 case CAPTURE_DEVICE_PROBE:
162 break;
163 }
164 }