[ODE] Bug or feature?

Jon Watte hplus-ode at mindcontrol.org
Fri Apr 8 09:40:25 MST 2005

> Now I want to use the same buffer for both, I created the VBO, had some 
> problems but finally worked them out, but the trimesh wouldnt collide 
> with my dBody.

The memory in a VBO is not valid to read after you have un-mapped the 
VBO, and you cannot draw out of a VBO that's currently mapped. Thus, 
you HAVE to keep your graphics data in a separate place from your 
collision data, if you want to use VBO. This is very similar to D3D 
vertex buffers, which have the same restriction.

Now, it could be that for some drivers, for some situations, doing 
something like that might work -- but probably only on your machine, 
and certainly not while you're attempting to demo to someone else, as 
it's explicitly defined as "not supported behavior" in the GL spec.

> So dVector3 is not really "3" at all but 4, this is causing errors in my 
> code, and I was wondering if there is a reason for having it this way.

This is documented in the ODE manual.

> So I am going to just change it to [3] and see what happens while I wait 
> for a reply :).

I would recommend against that. If you need to store your vertices in 
a custom array, I would just declare that array using my own float[3] 

> By the way, what about that autotools question I posted before? :)

If you have the time, you can make a change and add it to the unstable 
branch once it's working; I don't think anyone would mind.


			/ h+

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