Paul Martz wrote on Thursday, April 19, 2007 9:58 AM: > Good analysis. > > It occurs to me that there might be room for an enhancement to the > back-to-front sorting in the transparent bin such that it sorts based > on minimum distance rather than bounding volume center. > -Paul
That would be an improvement in some cases, but not in others (for example, a very large polygon with one nearby vertex and a smaller polygon farther than that vertex but nearer than all the other vertices of the large polygon). Unfortunately, pretty much whatever generic sorting strategy you use will have issues. What we really need is a BSP for the transparent stuff; that would ensure that they are always rendered in the right order. But that would require (1) a Nodekit for BSPs and (2) scenegraphs properly built with the BSPs. I'd love to do (1), but I have no time :( >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On Behalf Of Paul Speed >> Sent: Wednesday, April 18, 2007 9:32 PM >> To: osg users >> Subject: Re: [osg-users] translucent objects disappear >> >> (Two Pauls double-teaming...) >> >> I believe this comes down to the brute force way that OSG >> sorts drawables in the transparent bin. This is not always >> sufficient to ensure proper rendering order... and there's >> really not much OSG can do about either. At least not and >> still render in real time. >> >> If all of one type of object is inside of another and is >> frequently obscured by the outer object then you can use the >> bin numbers (setRenderBinDetails if my memory is good) to >> make sure the inside objects are always drawn before the >> outer. The problem you see happens because the outer object >> is drawn first and fills the Z-Buffer... when the interior >> objects go to draw they are obscured since the z-buffer >> doesn't know about that. >> >> Hopefully that isn't review. I think everyone on this list >> has hit this one time or another and the work-arounds always >> depend on the situation. >> Sometimes controlling rendering order with the relative bin >> numbers is a work-around. >> >> -Paul -- Bryan Thrall FlightSafety International [EMAIL PROTECTED] _______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
