Core Animation scaling bizarrely slow?

As part of an iPhone game, I've got buttons that grow a little when you press them, and shrink back when you release (as a way of responding to user input). The code responsible looks like this:

-(void) magnifyButton: (CALayer *) button
{
 button.transform = CATransform3DScale(button.transform, buttonPressScale, buttonPressScale, 1.0);
}

-(void) reduceButton: (CALayer *) button
{
 button.transform = CATransform3DScale(button.trans开发者_运维技巧form, 1.0 / buttonPressScale, 1.0 / buttonPressScale, 1.0);
}

This works great. But if I press a button (each of which is a small image on a CALayer) repeatedly, the animations going on in the background (in an OpenGL view) slow to 10 FPS. This seems absurd to me. I've found a similar problem here, but since I'm using implicit animations I'm not sure how I would go about optimizing in this case.

If anybody can offer a suggestion on how to make this run at a more reasonable speed, I'd be much obliged. Thanks in advance for you

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Before an animation begins, to save from having to render the CALayer for each frame, replace it with an image of itself:

button.shouldRasterize = YES;

When the animation is finished, set the property back to NO.

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Mixing UIKit and OpenGL is possible but will hurt performance. Things to avoid when combining the two are transparency and transformations. There's probably not a simple way to optimize this, best is ofcourse to do the buttons in OpenGL too.

Gamesfromwithin.com has a few good articles on combining UIKit and OpenGL. This article contains a section on performance (no solution though): http://gamesfromwithin.com/using-multiple-opengl-views-and-uikit

Also check out his presentation on combining the two: http://gamesfromwithin.com/wp-content/uploads/2010/03/GDC10_uikit_opengl.pdf