Re: Hi and pushing existing UserData from pointer

[Sam Roberts <vieuxtech@...>]

On Sun, Aug 16, 2009 at 9:49 AM, Chris Camacho<c.camacho@ntlworld.com> wrote:
> does actually work! I'm getting userdata of the appropriate
> type and if I add an impulse to the colliding shape the correct
> body moves so the above *must* be passing a userdata reference
> correctly, although what I suspect I'm doing is making a
> dummy user data with the pointer inside ???

no, lightuserdata and userdata are actually different value types in lua

> (This and some other "types" I'm going to remove from the
> lua GC, in any case as it make more sense to pass back these
> objects back to the library when you want to remove them
> from the simulation)
>
> Can you explain your method? can you provide a simple
> code example that shows your technique working?

See:

http://www.lua.org/pil/28.5.html

Pay special attention to the "weak" tables ref at end of the page,
weak tables are also described in the book.

Cheers,
Sam