Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!rutgers!mit-eddie!genrad!decvax!savax!elrond!amamaral From: amamaral@elrond.CalComp.COM (Alan Amaral) Newsgroups: comp.graphics Subject: Re: Point inside of polygon revisited... (It's easy) Message-ID: <1007@elrond.CalComp.COM> Date: Thu, 2-Jul-87 14:00:37 EDT Article-I.D.: elrond.1007 Posted: Thu Jul 2 14:00:37 1987 Date-Received: Sat, 4-Jul-87 08:49:58 EDT References: <948@elrond.CalComp.COM> <260@brandx.rutgers.edu> <1365@xanth.UUCP> <3772@spool.WISC.EDU> Organization: Calcomp, A Lockheed Company, Hudson, NH, USA Lines: 41 Keywords: ray tracing, graphics, polygon intersection In article <3772@spool.WISC.EDU>, planting@colby.WISC.EDU ( W. Harry Plantinga) writes: > In article <402@pembina.UUCP> obed!stephen@alberta.UUCP (Stephen > Samuel) writes: > > >If you feel that I am wrong here, please send me an actual counter-example. > > ^ > / \ > / \ > ray <-----------------/* \ > / \ > <_________> > > Does the point lie inside or outside of the triangle? If it is very > close to the edge of the triangle and if the angle of the edge is > appropriate, the precision of computation needed to get the right > answer can be surprisingly high. ^^^^^ ^^^^^ Please define "RIGHT"... I'm sure this problem has been suitably solved a number of times with INTEGER math, no more, but then again I'm sure the applicable definitions of "RIGHT" differ... By the way, handwaving does not "an actual counter-example" make. Please be more specific, like supply real NUMBERS, not vague pictures. "Very close to the edge" and "appropriate angle" are hard to calculate... > Harry Plantinga &^@%$ postnews... -- uucp: ...decvax!elrond!amamaral I would rather be a phone: (603) 885-8075 fool than a king... us mail: Calcomp/Sanders DPD (PTP2-2D01) Hudson NH 03051-0908