accelerometer smoothing delegate

gistfile1.txt

/*
 * This gives something resembling an average of the last 1/k values. A k-value of 0.5 will
 * give the current values equal weight with the previous smooth values, while a k-value of
 * 0.9 will let the current values only account for 10% of the new smooth value.
 *
 * This approach probably consumes a little less memory, and calculates a little faster,
 * than actually keeping an array of old values.
 */
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
    CGFloat x = acceleration.x;
    CGFloat y = acceleration.y;
    CGFloat k = 0.5;
    // smoothX and smoothY are ivars (CGFloat)
    smoothX = k * smoothX + (1.0 - k) * x;
    smoothY = k * smoothY + (1.0 - k) * y;
}