[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

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

--Oliver


-----------------------------------------------------------
You are currently subscribe to public_webgl@khronos.org.
To unsubscribe, send an email to majordomo@khronos.org with
the following command in the body of your email: