[ODE] BSP And ODE?

Sorce Code sorcecode at hotmail.com
Thu May 8 02:21:02 2003


Im sorry to say I have abandoned ODE usage in my project due to its 
incompatabliety with the BSP file structure.
I am going to write my own cut down engine for collision detection and 
object movement.
Using ODE in a project like this would be overkill anyway. Yes it would be 
nice to see objects boune around all over the BSP but I feel that the 
complexty that ODE code brings to the project is not required.
Thanks for all the support in the past.
Please feel free to e-mail me on the progress I make if this topic intrests 
you.


>From: "Mohammad Bilal" <prettyh8machine@mail.com>
>To: ode@q12.org
>Subject: Re: [ODE] BSP And ODE?
>Date: Thu, 08 May 2003 02:51:43 -0500
>
>
>So you're basically saying that instead of feeding OpenDE (or OPDCODE) with 
>triangles made out of visible faces, you just create triangles out of the 
>Quake2/3 map brushes and give them to OPCODE at the start and it'll take 
>care of itself making an optimized collision tree or whatever..??
>And you're sure that this whole making of triangles out of brushes at the 
>load time of the map isnt going to take much time ??
>
>Bilal
>
>----- Original Message -----
>From: "Nathan Ostgard" <nostgard@lvcm.com>
>Date: Wed, 7 May 2003 14:13:31 -0700
>To: <ode@q12.org>
>Subject: Re: [ODE] BSP And ODE?
>
> > The collision detection between all three games is very similar, so
> > what you know for Quake 2 is pretty valid for Quake 3 as well.
> >
> > You're correct that the visible face list gives you something that is
> > ready to stick directly into OPCODE, but that doesn't mean it's the
> > _correct_ thing to stick into OPCODE. All of the collision information
> > specified by the map designer is stored in the brushes and brush
> > planes... if you eliminate these and use the triangles intended for
> > rendering instead, you're throwing out a lot of useful information. In
> > my opinion, if you're trying to write something to use maps that were
> > intended for Quake 3, that is a bad idea.
> >
> > If you're just using the Quake 3 map format, however, with your own
> > maps... then you can still take the brush method and not have any
> > problems. It simple takes a quick preprocessing step of converting the
> > brush planes into triangles. It's most likely quick enough that you
> > could do it in real time. I say most likely because I haven't had a
> > chance to actually try it out, yet. The source code is already out
> > there, though - all of the Quake compiling tools do it, because the
> > map is stored as brushes before you compile it to BSP.
> >
> > The conversion is trivial... simply take each brush, create a large
> > polygon from the first plane, and do the same for each plane in the
> > brush, clipping the other polygons as necessary. Then convert this
> > into triangles. It's not very computationally intensive. When you're
> > finished, you have a simplified set of triangles to throw into OPCODE.
> >
> > It's no different from using the faces in the end... you're simply
> > taking one extra step in order to use the information that was
> > intended for collision detection.
> >
> > - Nathan Ostgard
> >
> > ----- Original Message -----
> > From: "Marco Grubert" <mgrubert@conitec.net>
> > To: <ode@q12.org>
> > Sent: Wednesday, May 07, 2003 1:27 PM
> > Subject: Re: [ODE] BSP And ODE?
> >
> >
> > > Hi,
> > > I only know the Quake 1/2 specifications- maybe they have changed
> > things-
> > > then just ignore my post.
> > > The visible face list gives you ready to use polygons that can be
> > put into
> > > opcode, as opposed to mere BSP splitting planes that would need to
> > be
> > > evaluated to a mesh before they can be used for collision detection-
> > so you
> > > would have some severe runtime overhead. BSPs are fine for spheres
> > of
> > > pre-determined size, but for general collision detection, it's a
> > headache.
> > >
> > > One other question though: if you use leaf data from a Quake tree,
> > how do
> > > you deal with 0-volume meshes? I am storing the visible leaf faces
> > in a
> > > tricollider on a per-leaf basis. This works fine, unless there is
> > only one
> > > face per leaf in which case severe hacking seems to be required in
> > order to
> > > prevent crashes.
> > >
> > > - Marco Grubert
> > >
> > > _______________________________________________
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> > > ODE@q12.org
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> >
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>
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