[project1dev] Re: collision detection

  • From: Chris Riccobono <crysalim@xxxxxxxxx>
  • To: project1dev@xxxxxxxxxxxxx
  • Date: Wed, 13 May 2009 14:42:45 -0700

That russian box thing you described sounds great for handling this
kind of thing too Alan, and having those created and placed in the
editor would help tons!  I hope you add that :)


On Wed, May 13, 2009 at 2:34 PM, Alan Wolfe <alan.wolfe@xxxxxxxxx> wrote:
> 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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