Question

i am working on an application which is based on accelerometer.

i have a ball which moves on the basis of acclerometer.

i have tried to bound the area of ball in about 320 by 480.

but when the ball reaches one of the corner, the ball gets out of bounded area and gets disappear, and comes again from anywhere.

i have no idea what i am doing wrong.

here is the code i m using

static inline BOOL bounce(float* val, float* delta, float min, float max) {
#define FLIP(val, c) (c - (val - c))
    if (*val < min || *val > max) {
        *delta = -(*delta * 0.00);
        float loc = *val < min ? min : max;
        *val = FLIP(*val, loc);
        return YES;
    } 
    return NO;
}


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

    #define CAP(val, max) (val < -max ? -max : (val > max ? max : val))
    CGPoint delta = CGPointMake(CAP(self.delta.x + acceleration.x, 1.5),CAP(self.delta.y - acceleration.y, 1.5));
    CGPoint location = CGPointMake(self.location.x + delta.x, self.location.y + delta.y);
    if (fabsf(acceleration.x) > kAccelerationThreshold || fabsf(acceleration.y) > kAccelerationThreshold || fabsf(acceleration.z) > kAccelerationThreshold)
    {
    }
    if (bounce(&location.x, &delta.x,20, self.view.bounds.size.width - 25 ) || bounce(&location.y, &delta.y,20, self.view.bounds.size.height - 20))
    {//25, 20
        AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);
    }    
    self.delta = delta;
    self.location = location;
    self.ballView.center = self.location;
}

waiitng for reply
regards

Answer 1

Solved.

taken 2 int values and bounded x between 0 and 320
and y in between 0 and 480.

thanks anyways