From: Keith W. <ke...@tu...> - 2003-01-08 16:46:44
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Dieter N=FCtzel wrote: > Am Mittwoch, 8. Januar 2003 17:04 schrieb Keith Whitwell: >=20 >>>What "clobbering" is allowed can be inferred from the GLX specificatio= n. >>> If you overlook DBE for a second, I believe we are meeting the >>>requirements of the spec, so I wouldn't say we're "broken". >> >>This isn't true. >> >>Consider when a diagonal line is drawn by Xlib across the active GL win= dow, >>with pages flipped. >> >>--> Xlib draws in the "back buffer" >>--> Shadow copies the bounding box of the line to the front buffer, >>including *all* of the backbuffer. >> >>What you really want is just a line to be drawn in the front buffer, bu= t in >>fact you get a whole lot of garbage with it. >> >>A common place things like this occur is in opaque window moves -- if y= ou >>move the 3d window when pages are flipped, its contents are replaced wi= th >>whatever's in the backbuffer. >> >>A solution to this is to get Xlib and GL to agree which is the front bu= ffer >>and always have Xlib draw into that & copy to the backbuffer. >=20 >=20 > Then this must be the culprit for the massive 3D window flickring (mixi= ng=20 > front and back buffer, but only when textures are involved, ipers but n= ot=20 > gears) when I move the window around? >=20 Yes, though nothing to do with textures -- gears is just too fast to see = it=20 flickering, whereas ipers is quite slow. Keith |