Top-down physics support

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Top-down physics support

Postby mbue » Tue Sep 30, 2008 9:18 am

Hello everybody. Just found chipmunk some time ago. Looks very promising 8)

As slembcke mentioned in a previous thread there are some problems with top-down simulations right now and how he plans to improve this.

So my intention with this mail is to collect information what would be needed to make top-down simulations work (better).
My reason to do this is that I'm currently working on a networked open source top down racing game, and right now the only thing i use from chipmunk is the collision code (using it very amateurish at that).

Before continuing I need to say that I did not read every possible documentation for chipmunk (yet), so some of the stuff below could be possible already. If so please feel free to correct me :)

Not to the top-down requirements:
slembcke already mentioned the most important thing:
Top-Down Friction - Not sure if there is a better name for this. Currently Chipmunk works really well for games viewed from the side, but not from the top. You can simulate a coin rolling across a table on it's edge, but not sliding on it's face.

Area friction?
I guess this could be implemented by defining an area (could work like inverse collision shapes) that provides the friction and other properties if an object is moved over it. The engine would need to check if an object is inside the area and plly the friction physics etc... to it.

Also: Generic friction for a cpSpace. Should get overwritten by area friction.

3) I'm not sure if that could be solved with joints, but a way to make the direction of e.g. rotatable (relative to the main body) tires for a moving car handled correctly. (i.e. movement is redirected towards the direction of the tires ... at least until friction is not effective any more).

Anybody got more requirements and maybe some suggestions how to ímplement this in chipmunk?


EDIT: There is some nice information about top-down simulation in chipmunk in this thread: "Simulating vehicle body"

PS: If anybody wants to join the racing project just contact me, there is no official site yet.
It supposed to get somewhere near the original Micro Machines game but with network support and pimped graphics&physics.
I have a basic engine running wit a nice collision map generator (polygons, circles, spawn points) in blender.
The network stuff is more or less running (needs fine-tuning) and the controls themselves still need a lot of tweaking, but that is simply a matter of math&physics-skills and time.
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Re: Top-down physics support

Postby bennysce » Sat Oct 04, 2008 3:25 am

I agree. I'm sure many more of us make top-down games so a bit more native support for it (i.e friction instead of gravity) would make it nicer to develop with even if there are "hacks" to make it work already..
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Re: Top-down physics support

Postby tartley » Fri Oct 10, 2008 8:02 am

For the record, I'd be keen to see top down support (friction somewhat like as described above) for use in shoving shapes around on a plane (ie. not a driving game - that sounds hard :-)
Tartley - Jonathan Hartley,
Using Pymunk (Chipmunk's Python bindings) for a game project:
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Location: London, England

Re: Top-down physics support

Postby Dave » Wed Nov 05, 2008 12:54 am

Hi... I was going to add a feature request, but I scanned the forum before creating a new thread and found this... I figured I might as well post here, since I think it applies. Anyway...

Would it be possible to have separate damping functions for angular/linear damping? It seems like this would be ideal, in certain situations.

Have fun! :)
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