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