[ODE] Large groups of inactive objects

[Erwin de Vries]

> nlin at nlin.net wrote:
> > With the recent talk about the future plans for turning on/off bodies
> > or entire islands, I wanted to ask about the current best way of
> > handling large groups of inactive items.
>
> currently ODE is deficient in this area. but actually the very next
> thing on my todo list is:
>   * ability to add and remove bodies and joints from the world, so
>     they can be "idle" and not attached to anything. this will
>     effectively make them inactive. removing an object from a world
>     will not destroy it.
>   * possibly some utility functions to copy the complete state from
>     one body/joint to another. this will make it easy to clone worlds.
>   * functions to enumerate all bodies/joints in a world.
>
> comments?

* dBodyEnable(), dBodyDisable(), int dBodyIsEnabled() using an internal
dxBodyEnabledFlag. When it is enabled it is enabled for island processing.
If its not enabled its ignored in island processing. This works very well
for us.