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View Full Version : GL_NV_OCCLUSION_QUERY replacement in SW ? how to something similar ?



DJSnow
02-18-2003, 06:41 AM
All of us know about the existance of the nVidia extension "GL_NV_OCCLUSION_QUERY" and its capabilites;
my problem is, that i need a way to do something similar _without_ using this extension.
Yes, i know about frustum-culling - but as you know "occlusion querying" goes one step ahead: not only querying what's in the frustum, but detecting which objects of the ones already in the frustum should be drawn.
I'm already using frustum-culling, but occlusion queryin (or soemthing like that) would be more powerful, i think.

What do you say ? Is there a way or technique to do something comparable in software ?

flo
02-18-2003, 07:29 AM
You could tag visible objects in the stencil buffer and then copy the stencil buffer to main memory to count the number of tagged pixels. I would not expect good performance, though.

flo

harsman
02-18-2003, 08:10 AM
Read this (http://www.hybrid.fi/download/dpvs_online.pdf) .

DJSnow
02-18-2003, 08:19 AM
@harsman:

*laugh*
yes, 2 minutes ago i stumbled over this link, too ! http://www.opengl.org/discussion_boards/ubb/smile.gif