[ODE] Proposal: Change Heightfield Origin

[David Walters]

> 1) I believe it actually complicates things, and it is easy to apply the offset manually anyway.
> 2) I think neither origin is 'correct' (or wrong), therefore I suggest we keep it as simple as possible (the way it is now).
>
> Or perhaps we can make this optional somehow?
>

I've had a chance at changing this functionality now and it didn't go
very well. It's less efficient to do it naively and too significant a
change to totally redo for a different origin. I'm also getting
paranoid about offseting by half_width and half_depth which sounds
like a good way of introducing precision errors. I'm thinking that it
should be left as it is now...

If the geom was going to be used as a dynamic object then i'd push
hard to change this, but as it's a collision oriented type I think
that it's not such an important issue.




> Reminds me of something else, I think the we should make the 'float' data path
> precision-independent. If you are building with double precision, you need to pass the heightfield
> data as doubles, which is rather undesirable (my mistake really).

I agree it is misleading - I'll make this change.  in future a double
precision path could be added on very easily, so if a feature request
pops up for that then it won't be hard to add.

Regards,
Dave.