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I'm playing around with the GLPaint Example from Apple.

But I don't know how to create an effect which fades the already drawn stuff out. I created an example in Flash which shows the effect I'm looking for: http://staging.rwichmann.com/openglexample/

In Flash I'm drawing a texture on a BitmapData and in every frame I'm adding a ColorTransform to the BitmapData which fades out the old drawn data.

I guess there must be a similar solution in openGL. Something with the renderBuffer or frameBuffer but I didn't find any solution.

Do you have an idea, tip, hint?

Adam Wagner
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Raphael
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1 Answers1

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Just a suggestion. Not really that code related, it's art related. Create a long trailing art with diminishing alpha values until at the end of the art the graphic is transparent. Rotate and scale as necessary to match the turns and directions of the lead object. This can be overly simplified but will also work with Quartz. If you go 3D you have to consider the rendering direction to the camera and apply a similar series of fading alpha textures.

sorry, no real code to show you.

Best regards, Natchaphon

Natchaphon S.
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