Re: copy z-buffer with scaling on iR

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Rob Jenkins (robj++at++quid)
Mon, 20 Oct 1997 13:39:06 -0700

On Oct 20, 11:19am, Hansong Zhang wrote:
> Subject: copy z-buffer with scaling on iR
> Hello everyone,
>
> I have a problem copying the Z-buffer (framebuffer to framebuffer)
> with a zoom factor. I was to copy a 512x512 area to 256x256, with a
> zoom factor of 0.5. My code works on Max Impacts but not on iR, where
> the destination 256x256 area is empty after the copy.
>

Here's a few pieces of info that would help narrow this down quickly:

Do you have a small piece of code to test this with ?
Are you using IrisGl or OpenGL ?
Do you have latest iR gfx patches ? ( 1808 for Onyx, 2191 for Onyx2 )
Does it work with no zoom ? ( or other values of zoom )
Does glCopyPixels return any GL error ? The quick/easy test would be just run
it through ogldebug and turn on GL error checking. If OpenGL thinks you did a
GL_INVALID_OPERATION say it might just not transfer any pixels and carry on.
Do you have zbuffering etc enabled when you do the copy ?
Do you have a multisampled visual ( and so a multisampled zbuffer ) ?

Cheers
Rob
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