OOOpenALController.m

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/*
 
OOOpenALController.m
 
 
Oolite
Copyright (C) 2004-2013 Giles C Williams and contributors
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
 
This program 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 General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA.
 
*/
 
#import "OOOpenALController.h"
#import "OOLogging.h"
#import "OOALSoundMixer.h"
 
static id sSingleton = nil;
 
@implementation OOOpenALController
 
+ (OOOpenALController *) sharedController
{
    if (sSingleton == nil)
    {
        sSingleton = [[self alloc] init];
    }
    
    return sSingleton;
}
 
 
- (id) init
{
    self = [super init];
    if (self != nil)
    {
        NSArray             *arguments = nil;
        NSEnumerator        *argEnum = nil;
        NSString            *arg = nil;
    
        arguments = [[NSProcessInfo processInfo] arguments];
        for (argEnum = [arguments objectEnumerator]; (arg = [argEnum nextObject]); )
        {
            if ([arg isEqual:@"-nosound"] || [arg isEqual:@"--nosound"])  
            {
                [self release];
                return nil;
            }
        }
 
        ALuint error;
        device = alcOpenDevice(NULL); // default device
        if (!device)
        {
            OOLog(kOOLogSoundInitError, @"%@", @"Failed to open default sound device");
            [self release];
            return nil;
        }
        context = alcCreateContext(device,NULL); // default context
        if (!alcMakeContextCurrent(context))
        {
            OOLog(kOOLogSoundInitError, @"%@", @"Failed to create default sound context");
            [self release];
            return nil;
        }
        if ((error = alGetError()) != AL_NO_ERROR)
        {
            OOLog(kOOLogSoundInitError,@"Error %d creating sound context",error);
        }
        OOAL(alDistanceModel(AL_NONE)); 
    }
    return self;
}
 
 
- (void) setMasterVolume:(ALfloat) fraction
{
    OOAL(alListenerf(AL_GAIN,fraction));
}
 
- (ALfloat) masterVolume
{
    ALfloat fraction = 0.0;
    OOAL(alGetListenerf(AL_GAIN,&fraction));
    return fraction;
}
 
// only to be called at app shutdown
// is there a better way to handle this?
- (void) shutdown
{
    [[OOSoundMixer sharedMixer] shutdown];
    OOAL(alcMakeContextCurrent(NULL));
    OOAL(alcDestroyContext(context));
    OOAL(alcCloseDevice(device));
}
 
@end