From sbaker@link.com Tue May 26 07:55:03 1998 X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1540" "Tue" "26" "May" "1998" "07:54:04" "-0500" "Steve Baker" "sbaker@link.com" nil "40" "Re: Question" "^From:" nil nil "5" nil nil nil nil nil] nil) X-VM-Last-Modified: (13793 54640 649954) X-VM-IMAP-Retrieved: nil X-VM-POP-Retrieved: nil X-VM-Message-Order: (1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26) X-VM-Summary-Format: "%n %*%a %-17.17F %-3.3m %2d %4l/%-5c %I\"%s\"\n" X-VM-Labels: ("r") X-VM-VHeader: ("Resent-" "From:" "Sender:" "To:" "Apparently-To:" "Cc:" "Subject:" "Date:") nil X-VM-Bookmark: 20 Received: from lfkw10.bgm.link.com (bgm.link.com [130.210.2.10]) by meserv.me.umn.edu (8.8.8/8.8.8) with ESMTP id HAA28563 for ; Tue, 26 May 1998 07:55:02 -0500 (CDT) Received: from borgus.bgm.link.com (borgus.bgm.link.com [130.210.236.13]) by lfkw10.bgm.link.com (8.8.6/HTI-Hack-8.8.4) with SMTP id HAA00068 for ; Tue, 26 May 1998 07:54:55 -0500 (CDT) X-Sender: steve@borgus.bgm.link.com Reply-To: Steve Baker In-Reply-To: <199805230429.XAA10965@kenai.me.umn.edu> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII From: Steve Baker To: "Curtis L. Olson" Subject: Re: Question Date: Tue, 26 May 1998 07:54:04 -0500 (CDT) On Fri, 22 May 1998, Curtis L. Olson wrote: > I'm running into floating point problems again where my scenery tiles > sometimes have a pixel gap between them. I was wondering if you had > any ideas ... It's a problem that plagues us too. I can't say that I have a magic solution. One thing I have *considered* is to do everything in integers (for the terrain skin at least). This sounds counter-intuitive - but the source data for your terrain is certainly not accurate to better than a meter - and integers have the huge advantage that they don't suffer from roundoff error providing all you do is add and subtract them. However, I havn't had the nerve to try this yet - right now, we kludge the edges of each terrain tile to make it a teeny-tiny bit too big. The resulting overlap is very small - but enough to get rid of the cracks. > Anyways, what this forces me to do is for each tile I must > glTranslate() by center_of_tile_to_be_drawn - center_of_tile_I'm_in. > But, up until this point everything was done in double's so I was > hoping the final translate about which is on the order of 20,000 - > 30,000 meters would be ok. But that translate could be done in integer meters. > Anyways, I just thought I'd see if you had any brilliant thoughts on > the subject. Nope - it's a continual problem for me too. 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