[project1dev] Re: collision detection

  • From: Alan Wolfe <alan.wolfe@xxxxxxxxx>
  • To: project1dev@xxxxxxxxxxxxx
  • Date: Wed, 13 May 2009 14:34:06 -0700

but you are right, sometimes we want collision areas other than what the
model gives.

Im starting to think being able to place invisible collision objects via the
editor may be the way to go (and of course they can be created, destroyed
and manipulated from script too!)
On Wed, May 13, 2009 at 2:23 PM, Alan Wolfe <alan.wolfe@xxxxxxxxx> wrote:

> it does cheaper bounding volume tests for intersection so performance wise
> it's ok.
>
> like for instance, the game does a test for collision against an imaginary
> sphere that surrounds every object before doing it per poly.
>
> im working on something right now that organizes everything in the world
> into recursive boxes (think russian doll style where one box has 8 boxes in
> it, and those 8 boxes each have 8 more boxes in it etc).
>
> So that way if you know soemthing doesnt collide with a box, you dont have
> to test any of the boxes inside of that box, or any of the objects inside of
> that box or any of it's children.
>   On Wed, May 13, 2009 at 2:00 PM, Chris Riccobono <crysalim@xxxxxxxxx>wrote:
>
>> Your example question - it would help for things like wires, ropes,
>> fences, and other things that we can't rely on collision for.  Also I
>> think I remember you saying that models that are walkable use more
>> resources, so if we just used invisible barriers at certain areas and
>> made all the models behind them ignore, that might be easier?
>>
>> On Wed, May 13, 2009 at 9:56 AM, Alan Wolfe <alan.wolfe@xxxxxxxxx> wrote:
>> > yeah we can deffinately do that, just put an invisible impassible box.
>> >
>> > what would be an example of that coming up I'm wondering?
>> >
>> > On Wed, May 13, 2009 at 9:28 AM, Chris Riccobono <crysalim@xxxxxxxxx>
>> wrote:
>> >>
>> >> Yeah, I did notice this, and it makes me wonder, what should we do
>> >> about things we don't want the player to be able to pass through but
>> >> doesn't have a model blocking them?
>> >>
>> >> Do we just put invisible models in that let the player not pass?
>> >>
>> >> On Tue, May 12, 2009 at 8:58 PM, Alan Wolfe <alan.wolfe@xxxxxxxxx>
>> wrote:
>> >> > ok then ill leave it and see if anyone complains :P
>> >> >
>> >> > On Tue, May 12, 2009 at 8:55 PM, Kent Petersen <kentkmp@xxxxxxxxx>
>> >> > wrote:
>> >> >>
>> >> >> Yeah, I've known for a while. I kinda like it. I was thinking about
>> >> >> just
>> >> >> making more rocks fall to prevent the player from passing
>> >> >>
>> >> >> On Tue, May 12, 2009 at 8:51 PM, Alan Wolfe <alan.wolfe@xxxxxxxxx>
>> >> >> wrote:
>> >> >>>
>> >> >>> im not sure if anyone else has noticed but you can jump over the
>> >> >>> boulders
>> >> >>> that fall from the sky (just hump them and jump).
>> >> >>>
>> >> >>> And same thing w/ erics mine cart, you can hump it and jump and get
>> >> >>> in.
>> >> >>>
>> >> >>> Right now all our collision detection is model based, the player is
>> >> >>> actually just a single point in space, and when he moves, he
>> collides
>> >> >>> against the actual faces of the polygons that are marked as
>> >> >>> collidable.
>> >> >>>
>> >> >>> We'll probably have to do something like specify a collision shape
>> >> >>> independant from the model, like say "yes this mine cart is
>> >> >>> collidable, but
>> >> >>> just do collision against a bounding box, instead of against the
>> >> >>> geometry
>> >> >>> itself".  Or for the rocks, a cylinder might make more sense.
>> >> >>> shrug...
>> >> >>>
>> >> >>> anyhow, just FYI it's on the radar if anyone did notice!
>> >> >>
>> >> >
>> >> >
>> >>
>> >
>> >
>>
>>
>

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