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
|
/*
Simple DirectMedia Layer
Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_internal.h"
// Output audio to nowhere...
#include "../SDL_sysaudio.h"
#include "SDL_dummyaudio.h"
#if defined(SDL_PLATFORM_EMSCRIPTEN) && !defined(__EMSCRIPTEN_PTHREADS__)
#include <emscripten/emscripten.h>
#endif
static bool DUMMYAUDIO_WaitDevice(SDL_AudioDevice *device)
{
SDL_Delay(device->hidden->io_delay);
return true;
}
static bool DUMMYAUDIO_OpenDevice(SDL_AudioDevice *device)
{
device->hidden = (struct SDL_PrivateAudioData *) SDL_calloc(1, sizeof(*device->hidden));
if (!device->hidden) {
return false;
}
if (!device->recording) {
device->hidden->mixbuf = (Uint8 *) SDL_malloc(device->buffer_size);
if (!device->hidden->mixbuf) {
return false;
}
}
device->hidden->io_delay = ((device->sample_frames * 1000) / device->spec.freq);
const char *hint = SDL_GetHint(SDL_HINT_AUDIO_DUMMY_TIMESCALE);
if (hint) {
double scale = SDL_atof(hint);
if (scale >= 0.0) {
device->hidden->io_delay = (Uint32)SDL_round(device->hidden->io_delay * scale);
}
}
// on Emscripten without threads, we just fire a repeating timer to consume audio.
#if defined(SDL_PLATFORM_EMSCRIPTEN) && !defined(__EMSCRIPTEN_PTHREADS__)
MAIN_THREAD_EM_ASM({
var a = Module['SDL3'].dummy_audio;
if (a.timers[$0] !== undefined) { clearInterval(a.timers[$0]); }
a.timers[$0] = setInterval(function() { dynCall('vi', $3, [$4]); }, ($1 / $2) * 1000);
}, device->recording ? 1 : 0, device->sample_frames, device->spec.freq, device->recording ? SDL_RecordingAudioThreadIterate : SDL_PlaybackAudioThreadIterate, device);
#endif
return true; // we're good; don't change reported device format.
}
static void DUMMYAUDIO_CloseDevice(SDL_AudioDevice *device)
{
if (device->hidden) {
// on Emscripten without threads, we just fire a repeating timer to consume audio.
#if defined(SDL_PLATFORM_EMSCRIPTEN) && !defined(__EMSCRIPTEN_PTHREADS__)
MAIN_THREAD_EM_ASM({
var a = Module['SDL3'].dummy_audio;
if (a.timers[$0] !== undefined) { clearInterval(a.timers[$0]); }
a.timers[$0] = undefined;
}, device->recording ? 1 : 0);
#endif
SDL_free(device->hidden->mixbuf);
SDL_free(device->hidden);
device->hidden = NULL;
}
}
static Uint8 *DUMMYAUDIO_GetDeviceBuf(SDL_AudioDevice *device, int *buffer_size)
{
return device->hidden->mixbuf;
}
static int DUMMYAUDIO_RecordDevice(SDL_AudioDevice *device, void *buffer, int buflen)
{
// always return a full buffer of silence.
SDL_memset(buffer, device->silence_value, buflen);
return buflen;
}
static bool DUMMYAUDIO_Init(SDL_AudioDriverImpl *impl)
{
impl->OpenDevice = DUMMYAUDIO_OpenDevice;
impl->CloseDevice = DUMMYAUDIO_CloseDevice;
impl->WaitDevice = DUMMYAUDIO_WaitDevice;
impl->GetDeviceBuf = DUMMYAUDIO_GetDeviceBuf;
impl->WaitRecordingDevice = DUMMYAUDIO_WaitDevice;
impl->RecordDevice = DUMMYAUDIO_RecordDevice;
impl->OnlyHasDefaultPlaybackDevice = true;
impl->OnlyHasDefaultRecordingDevice = true;
impl->HasRecordingSupport = true;
// on Emscripten without threads, we just fire a repeating timer to consume audio.
#if defined(SDL_PLATFORM_EMSCRIPTEN) && !defined(__EMSCRIPTEN_PTHREADS__)
MAIN_THREAD_EM_ASM({
if (typeof(Module['SDL3']) === 'undefined') {
Module['SDL3'] = {};
}
Module['SDL3'].dummy_audio = {};
Module['SDL3'].dummy_audio.timers = [];
Module['SDL3'].dummy_audio.timers[0] = undefined;
Module['SDL3'].dummy_audio.timers[1] = undefined;
});
impl->ProvidesOwnCallbackThread = true;
#endif
return true;
}
AudioBootStrap DUMMYAUDIO_bootstrap = {
"dummy", "SDL dummy audio driver", DUMMYAUDIO_Init, true, false
};
|
