Proprosed break in libGL / DRI driver ABI

[Julien Lafon]

On Apr 5, 2005 10:11 PM, Brian Paul <brian.paul at tungstengraphics.com> wrote:
> Roland Mainz wrote:
> > Ian Romanick wrote:
> > When I look at xc/extras/Mesa/src/mesa/main/config.h I see more items on
> > my wishlist: Would it be possible to increase |MAX_WIDTH| and
> > |MAX_HEIGHT| (and the matching texture limits of the software
> > rasterizer) to 8192 to support larger displays (DMX, Xinerama and Xprint
> > come in mind) ?
> 
> If you increase MAX_WIDTH/HEIGHT too far, you'll start to see
> interpolation errors in triangle rasterization (the software
> routines).  The full explanation is long, but basically there needs to
> be enough fractional bits in the GLfixed datatype to accomodate
> interpolation across the full viewport width/height.
Will increasing MAX_WIDTH/HEIGHT affect applications which run in
small windows or only those which use resolutions exceeding the 4Kx4K
limit?

> 
> In fact, I'm not sure that we've already gone too far by setting
> MAX_WIDTH/HEIGHT to 4096 while the GLfixed type only has 11 fractional
> bits.  I haven't heard any reports of bad triangles so far though.
Do you know any specific application which may expose bad rendering
when the size gets to large?

> But there probably aren't too many people generating 4Kx4K images.
We've been running tests with the glutdemo applications and Xprint at
higher resolutions (6Kx8K window size) and did not notice any bad
rendering using the software rasterizer.

Julien
-- 
Julien Lafon
Senior Staff Engineer, Hitachi