From fatcity!root@news.cts.com Mon Apr 20 10:54:32 1998 X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["2073" "Mon" "20" "April" "1998" "07:50:34" "-0800" "Steve Baker" "sbaker@link.com" nil "54" "Re: How To Q: Off-screen object culling." "^From:" nil nil "4" nil nil nil nil nil] nil) Received: from mh2.cts.com (root@mh2.cts.com [205.163.24.68]) by meserv.me.umn.edu (8.8.8/8.8.8) with ESMTP id KAA05163 for ; Mon, 20 Apr 1998 10:54:29 -0500 (CDT) Received: from king.cts.com (root@king.cts.com [198.68.168.21]) by mh2.cts.com (8.8.7/8.8.5) with ESMTP id IAA15636; Mon, 20 Apr 1998 08:51:20 -0700 (PDT) Received: from donews.cts.com (root@donews.cts.com [192.188.72.21]) by king.cts.com (8.8.7/8.8.7) with SMTP id IAA29983; Mon, 20 Apr 1998 08:51:19 -0700 (PDT) Received: from fatcity by donews.cts.com with uucp (Smail3.1.29.1 #5) id m0yRI5D-00000Xa; Mon, 20 Apr 98 08:02 PDT Received: by fatcity.com (10-Feb-1998/v1.0f-b64/bab) via UUCP id 0001F042; Mon, 20 Apr 1998 07:50:34 -0800 Message-ID: X-Comment: OpenGL Game Developers Mailing List X-Sender: Steve Baker Reply-To: OPENGL-GAMEDEV-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com Organization: Fat City Network Services, San Diego, California X-ListServer: v1.0f, build 64; ListGuru (c) 1996-1998 Bruce A. Bergman Precedence: bulk Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Transfer-Encoding: 7bit From: Steve Baker Sender: root@fatcity.com To: Multiple recipients of list OPENGL-GAMEDEV-L Subject: Re: How To Q: Off-screen object culling. Date: Mon, 20 Apr 1998 07:50:34 -0800 On Sat, 18 Apr 1998, Jason Maskell wrote: > This is probably an FAQ, but I'm to the point now where I need to be > able to tell when one of my objects is offscreen and not even send it > down the pipe. This would be pretty simple if I was using glFrustum, > but I'm not at the moment. I could switch, but I haven't quite got my > head around how to get the same results as I get using glPerspective.. > If someone can point me to some code that does some simple pre-culling, > I would be most grateful.. > Well, if you can do it with glFrustum then you can do it with gluPerspective. Note that gluPerspective simply calls glFrustum. It's like this: void APIENTRY gluPerspective( GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar ) { GLdouble xmin, xmax, ymin, ymax; ymax = zNear * tan( fovy * M_PI / 360.0 ); ymin = -ymax; xmin = ymin * aspect; xmax = ymax * aspect; glFrustum( xmin, xmax, ymin, ymax, zNear, zFar ); } [This is actually the source code for gluPerspective from the Mesa library - but since it only involves regular OpenGL API, it should work on any OpenGL implementation] > BTW, I've bought the red book finally... Always a good move. I have yet to hear anyone who regretted it. Steve Baker (817)619-8776 (Vox/Vox-Mail) Raytheon Systems Inc. (817)619-4028 (Fax) Work: SBaker@link.com http://www.hti.com Home: SJBaker1@airmail.net http://web2.airmail.net/sjbaker1 -- Author: Steve Baker INET: sbaker@link.com Fat City Network Services -- (619) 538-5051 FAX: (619) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB OPENGL-GAMEDEV-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).