2048 size limit on virtual displays
brian.paul at tungstengraphics.com
Tue Apr 29 07:27:27 PDT 2008
Keith Packard wrote:
> On Tue, 2008-04-29 at 00:32 +0100, Albert Vilella wrote:
>> is this on a i965? can this be used for a i945?
> Nope, the i945 has a hardware limit of 2048x2048 for textures and 3d
> rendering targets. The i965 has a 8192x8192 limit, but Mesa has a
> 4096x4096 limit, so I set the i965 driver to that value. At some point,
> perhaps Mesa will be fixed to handle larger outputs, but that appears
> difficult given the existing Mesa software rendering stack.
To be more specific, the issue is in triangle rasterization using fixed
point arithmetic. You can set MAX_WIDTH/HEIGHT to 8192 in
src/mesa/main/config.h and things would probably be fine for the most
part. But in some situations, particular triangles might be slightly
mis-rendered. Most people never notice/care, but in some applications,
tiny errors in triangle rasterization are significant.
There are additional comments in src/mesa/swrast/s_tritemp.h
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