wipe off effect in iphone game
<p>I am developing an iphone game, which needs to wipe off the brain goo splashed on the screen by fingers. </p>

<p>When I wipe the screen with my finger, it works well on simulater, but when I test it on my device, the track on the screen is totally different from the track of my finger. </p>

<p>It seems that they are in opposite direction. </p>

<p>For example, If I wipe the the upper half of the screen, the track I got is on the bottom half of the screen. </p>

<p>Anybody can help me? Does CCRenderTexture performs different on Simulater and real device? </p>
