/** * OpenAL cross platform audio library * Copyright (C) 2010 by Chris Robinson * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library 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 * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. * Or go to http://www.gnu.org/copyleft/lgpl.html */ #include "config.h" #include <stdlib.h> #include "alMain.h" #include "AL/al.h" #include "AL/alc.h" typedef struct { volatile int killNow; ALvoid *thread; } null_data; static const ALCchar nullDevice[] = "No Output"; static ALuint NullProc(ALvoid *ptr) { ALCdevice *Device = (ALCdevice*)ptr; null_data *data = (null_data*)Device->ExtraData; ALuint now, start; ALuint64 avail, done; const ALuint restTime = (ALuint64)Device->UpdateSize * 1000 / Device->Frequency / 2; done = 0; start = timeGetTime(); while(!data->killNow && Device->Connected) { now = timeGetTime(); avail = (ALuint64)(now-start) * Device->Frequency / 1000; if(avail < done) { /* Timer wrapped. Add the remainder of the cycle to the available * count and reset the number of samples done */ avail += (ALuint64)0xFFFFFFFFu*Device->Frequency/1000 - done; done = 0; } if(avail-done < Device->UpdateSize) { Sleep(restTime); continue; } while(avail-done >= Device->UpdateSize) { aluMixData(Device, NULL, Device->UpdateSize); done += Device->UpdateSize; } } return 0; } static ALCenum null_open_playback(ALCdevice *device, const ALCchar *deviceName) { null_data *data; if(!deviceName) deviceName = nullDevice; else if(strcmp(deviceName, nullDevice) != 0) return ALC_INVALID_VALUE; data = (null_data*)calloc(1, sizeof(*data)); device->szDeviceName = strdup(deviceName); device->ExtraData = data; return ALC_NO_ERROR; } static void null_close_playback(ALCdevice *device) { null_data *data = (null_data*)device->ExtraData; free(data); device->ExtraData = NULL; } static ALCboolean null_reset_playback(ALCdevice *device) { null_data *data = (null_data*)device->ExtraData; SetDefaultWFXChannelOrder(device); data->thread = StartThread(NullProc, device); if(data->thread == NULL) return ALC_FALSE; return ALC_TRUE; } static void null_stop_playback(ALCdevice *device) { null_data *data = (null_data*)device->ExtraData; if(!data->thread) return; data->killNow = 1; StopThread(data->thread); data->thread = NULL; data->killNow = 0; } static const BackendFuncs null_funcs = { null_open_playback, null_close_playback, null_reset_playback, null_stop_playback, NULL, NULL, NULL, NULL, NULL, NULL }; ALCboolean alc_null_init(BackendFuncs *func_list) { *func_list = null_funcs; return ALC_TRUE; } void alc_null_deinit(void) { } void alc_null_probe(enum DevProbe type) { switch(type) { case DEVICE_PROBE: AppendDeviceList(nullDevice); break; case ALL_DEVICE_PROBE: AppendAllDeviceList(nullDevice); break; case CAPTURE_DEVICE_PROBE: break; } }