fe6e532c87
This allows us to properly update the ALCdevice and its resources with the new parameters before starting playback, instead of expecting the mixer to block and wait after it has begun. This also lets us avoid holding the device lock while resetting and starting the device, which helps prevent lock inversion on some backends (ie, one thread locking A then B, and another thread locking B then A), ultimately allowing certain backends to asynchronously update the ALCdevice without risk of lockup. Capture still has issues here, however.
167 lines
3.9 KiB
C
167 lines
3.9 KiB
C
/**
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* OpenAL cross platform audio library
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* Copyright (C) 2010 by Chris Robinson
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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* Or go to http://www.gnu.org/copyleft/lgpl.html
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*/
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#include "config.h"
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#include <stdlib.h>
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#include "alMain.h"
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#include "AL/al.h"
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#include "AL/alc.h"
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typedef struct {
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volatile int killNow;
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ALvoid *thread;
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} null_data;
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static const ALCchar nullDevice[] = "No Output";
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static ALuint NullProc(ALvoid *ptr)
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{
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ALCdevice *Device = (ALCdevice*)ptr;
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null_data *data = (null_data*)Device->ExtraData;
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ALuint now, start;
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ALuint64 avail, done;
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const ALuint restTime = (ALuint64)Device->UpdateSize * 1000 /
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Device->Frequency / 2;
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done = 0;
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start = timeGetTime();
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while(!data->killNow && Device->Connected)
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{
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now = timeGetTime();
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avail = (ALuint64)(now-start) * Device->Frequency / 1000;
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if(avail < done)
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{
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/* Timer wrapped (50 days???). Add the remainder of the cycle to
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* the available count and reset the number of samples done */
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avail += ((ALuint64)1<<32)*Device->Frequency/1000 - done;
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done = 0;
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}
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if(avail-done < Device->UpdateSize)
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{
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Sleep(restTime);
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continue;
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}
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while(avail-done >= Device->UpdateSize)
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{
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aluMixData(Device, NULL, Device->UpdateSize);
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done += Device->UpdateSize;
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}
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}
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return 0;
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}
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static ALCenum null_open_playback(ALCdevice *device, const ALCchar *deviceName)
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{
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null_data *data;
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if(!deviceName)
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deviceName = nullDevice;
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else if(strcmp(deviceName, nullDevice) != 0)
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return ALC_INVALID_VALUE;
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data = (null_data*)calloc(1, sizeof(*data));
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device->szDeviceName = strdup(deviceName);
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device->ExtraData = data;
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return ALC_NO_ERROR;
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}
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static void null_close_playback(ALCdevice *device)
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{
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null_data *data = (null_data*)device->ExtraData;
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free(data);
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device->ExtraData = NULL;
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}
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static ALCboolean null_reset_playback(ALCdevice *device)
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{
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SetDefaultWFXChannelOrder(device);
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return ALC_TRUE;
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}
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static ALCboolean null_start_playback(ALCdevice *device)
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{
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null_data *data = (null_data*)device->ExtraData;
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data->thread = StartThread(NullProc, device);
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if(data->thread == NULL)
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return ALC_FALSE;
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return ALC_TRUE;
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}
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static void null_stop_playback(ALCdevice *device)
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{
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null_data *data = (null_data*)device->ExtraData;
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if(!data->thread)
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return;
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data->killNow = 1;
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StopThread(data->thread);
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data->thread = NULL;
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data->killNow = 0;
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}
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static const BackendFuncs null_funcs = {
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null_open_playback,
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null_close_playback,
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null_reset_playback,
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null_start_playback,
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null_stop_playback,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL
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};
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ALCboolean alc_null_init(BackendFuncs *func_list)
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{
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*func_list = null_funcs;
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return ALC_TRUE;
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}
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void alc_null_deinit(void)
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{
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}
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void alc_null_probe(enum DevProbe type)
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{
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switch(type)
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{
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case ALL_DEVICE_PROBE:
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AppendAllDeviceList(nullDevice);
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break;
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case CAPTURE_DEVICE_PROBE:
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break;
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}
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}
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