[iPhone] 만보기 로직

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

x = acceleration.x;

y = acceleration.y;

z = acceleration.z;

float dot = (x1 * x) + (py * y) + (z1 * z);

    float a = ABS(sqrt(x1 * x1 + py * py + z1 * z1));

    float b = ABS(sqrt(x * x + y * y + z * z));

    

    dot /= (a * b);

    if (dot<0.8) // bounce

    {

        if (!isChange)

        {

            isChange = YES;

            

_walkCnt  = _walkCnt+1;

            // count increases and all work done here

        } else {

            isChange = NO;

        }

    }

x1 = x;

py = y;

z1 = z;

}