cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   tomek
   Member

   Im down to my last bug before my app launch and haven't had much success with a solution for:

   I have an accelerometer, which I can successful stop/start, using:

   [UIAccelerometer sharedAccelerometer].delegate = self;
   [UIAccelerometer sharedAccelerometer].delegate = nil;

   However, if I move the iPhone will the accelerometer is disabled and then enable it, the accelerometer spits out the value(s) that were registered when it was disabled.

   Is there any way to clear these values?

   ... I will PayPal 25$ to the person that provides the solution

   Posted 1 year ago #
2. 

   leocck
   Member

   Hi tomek,
   I think you could use a flag to just ignore the 'first' accelerometer value(s).
   eg:
   - the flag is set to true
   - the accelerometer is enabled, the delegate methods are using the values due to the flag value
   - the accelerometer was disabled, set the flag to false
   - the accelerometer was re-enabled, the first(s) call(s) to the delegate methods will ignore the values, and set the flag to true again

   What do you think?

   Posted 1 year ago #
3. 

   tomek
   Member

   Hi leocck,

   Ive tried variations of the flag method, using if statements, while loops, etc.

   I have a feeling, its getting buffered somewhere, I'm just not sure where.

   Posted 1 year ago #
4. 

   leocck
   Member

   What is the behavior you're getting with this?

   I suppose something in your game is 'jumping', if that's the case, are you using interpolation calculations?

   Posted 1 year ago #
5. 

   tomek
   Member

   Basically what happens is the accelerometer calls a method, when x <-2.3, this method is just a simple counter, i.e countUp... within countUp a label is presented and the accelerometer is not re-enabled until it is pressed.... however if between that time you move the iphone it stores the x/y values and when you press the button, it spits them out.

   - (void)accelerometer:(UIAccelerometer*)accelerometer didAccelerate:(UIAcceleration*)acceleration{

   if(acceleration.x < -0.05)
   {
   start = CACurrentMediaTime();

   if(acceleration.x < -2.3)
   {
   stop = CACurrentMediaTime();

   velX = (10000 * (stop - start));

   if(velX > 6.0)
   {
   power = 6;
   }
   [UIAccelerometer sharedAccelerometer].delegate = NULL;
   autoTimer = [NSTimer scheduledTimerWithTimeInterval:0.08 target:self selector:@selector(countUp) userInfo:nil repeats:YES];

   }
   }

   }

   }

   Posted 1 year ago #
6. 

   cybergreg
   Member

   NULL and nil are not the same;
   try:
   

   power = 6;
   }
   [UIAccelerometer sharedAccelerometer].delegate = nil;

   I think I've also read about a tiny amount of accelerometer data being read. I'll check my links and post back

   Posted 1 year ago #
7. 

   tomek
   Member

   @cybergreg.... tried the nil... no dice.

   please let me know if you find anything in your links.

   Posted 1 year ago #
8. 

   cybergreg
   Member

   In theory you "should" be using a low-pass filter as shown in Apple's sample apps:

   #define kAccelerometerFrequency		60 // Hz
   #define kFilteringFactor			0.1 // For filtering out gravitational affects

   //Configure and start accelerometer
   		[[UIAccelerometer sharedAccelerometer] setUpdateInterval:(1.0 / kAccelerometerFrequency)];
   		[[UIAccelerometer sharedAccelerometer] setDelegate:self];

   //Use a basic low-pass filter in the accelerometer values
    accel[0] = acceleration.x * kFilteringFactor + accel[0] * (1.0 - kFilteringFactor);

   HTH and keep your money :-)

   Still looking for those old links...

   Posted 1 year ago #
9. 

   tomek
   Member

   @cybergreg

   Thanks so much for the code... I will give it a go.

   Posted 1 year ago #
10. 

    leocck
    Member

    @tomek, even with some things I didn't understand on your logic, are you sure something like that doesn't fits for you? (instead of disabling/enabling the accelerometer every time)

    - (void)accelerometer:(UIAccelerometer*)accelerometer didAccelerate:(UIAcceleration*)acceleration
    {
    
       if( theGameCanReadAccelerometerValues_Control )
    
             if(acceleration.x < -0.05)
             {
                start = CACurrentMediaTime();
    
                if(acceleration.x < -2.3)
                {
                   stop = CACurrentMediaTime();
    
                   velX = (10000 * (stop - start));
    
                   if(velX > 6.0)
                   {
                      power = 6;
                   }
                   [UIAccelerometer sharedAccelerometer].delegate = NULL;
                   autoTimer = [NSTimer scheduledTimerWithTimeInterval:0.08 target:self selector:@selector(countUp) userInfo:nil repeats:YES];
    
                }
             }
          }
       }
    
       else
       {
          // just ignore it
       }
    }

    Personally, I don't like to enable/disable things when the game is already running ...

    Posted 1 year ago #
11. 

    leocck
    Member

    Yes, like @cybergreg said, keep the money,
    OR, you could donate it do cocos2d-iphone project ;)

    Posted 1 year ago #
12. 

    cybergreg
    Member

    @leocck +1 - donate it to @Riq

    @tomek - WHERE do you call this code?
    [[UIAccelerometer sharedAccelerometer] setDelegate:self];
    on your buttonPress?

    perhaps
    [self performSelector@selector(enableAccelDelegate) withObject:self afterDelay:0.0];
    is your friend...

    where enableAccelDelegate is:
    

    -(void)enableAccelDelegate
    {
       [[UIAccelerometer sharedAccelerometer] setDelegate:self];
    }

    Posted 1 year ago #
13. 

    liquidfire
    Member

    @cybergreg For simplicity sake:
    [[UIAccelerometer sharedAccelerometer] performSelector@selector(setDelegate:) withObject:self afterDelay:0.0];

    Posted 1 year ago #
14. 

    tomek
    Member

    @cybergreg... that is correct regarding the start button.

    I used your suggestion... however same result....

    -(void) startButt
    {
    [self performSelector:@selector(enableAccelDelegate) withObject:self afterDelay:0.0];

    }

    -(void)enableAccelDelegate
    {
    [[UIAccelerometer sharedAccelerometer] setDelegate:self];
    }

    -(void) replay
    {
    button = [CCMenuItemImage itemFromNormalImage:@"replay.png" selectedImage:@"replay.png" target:self selector:@selector(startButt)];
    menu = [CCMenu menuWithItems:button, nil];
    menu.position =ccp(size.width/2, size.height/5);
    [self removeChild:fist cleanup:NO];
    [self addChild:menu];
    }

    Posted 1 year ago #
15. 

    cybergreg
    Member

    @liquidfire - awesome, didn't think of that...

    @tomek - sorry, I'm out...
    :-(

    Posted 1 year ago #
16. 

    tomek
    Member

    @cybergreg.... no worries, thanks.

    Posted 1 year ago #

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