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Re: [Public WebGL] readPixels and out of range pixels

On Feb 7, 2010, at 5:23 AM, Gregg Tavares wrote:

> I noticed the current spec doesn't appear to mention how out of range pixels are handled by calls to readPixels.
> The OpenGL ES 2.0 spec makes them undefined, meaning you can have a back buffer that is 10x10 but call glReadPixels with 100x100 and you'll get back something.
> That doesn't seem like it should go undefined in WebGL.
> Two solutions off the top of my head.
> 1) leave it the way it is but specified that out of range pixels are 0,0,0,0
> 2) return INVALID_OPERATION if any out of range pixels are requested.
> I think I'd prefer #2 because it makes it obvious when you are asking for something that is not part of the current framebuffer unless there is some other reason to go with #1.

I prefer #1 as it's consistent with the canvas2d getImageData API


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