iPhone: Layering a transparent openGL view on top of a UIView?

Question

I am working on iPhone app and I have an openGL view rendering on top of a regular UIView. It's working, but I can't seem to get the openGL view to have a transparent background that shows the UIView underneath. Instead, I get a big black box.

I have tried setting the background color to UIColor clearColor, I've set opaque to NO, I've set glClearColor to 0.0,0.0,0.0,0.0.

I think I'm misunderstanding/misusing something related to blend modes, but I'm not sure. Can anyone give me a bit of sample code which shows how to do this?

Thanks in advance.

Answer 1

Check the color format of your view. If you’ve set it to kEAGLColorFormatRGB565 via the drawableProperties dictionary, the alpha channel of the view’s contents will be implicitly treated as 1.0, regardless of what you draw into it.