Re: Cooperative Multitasking

[Bret Mogilefsky <mogul@...>]

On Thu, Oct 19, 2000 at 11:36:05PM +0200, Jeroen Janssen wrote:
> lemkef@execpc.com wrote:
[...]
> > and such.  Bret Mogilefsky mentioned how it was done with Grim
> > Fandango and it sounds like the same problem / solution.  a link to
[...]
> > There were some other discussions, on the same topic, but they were a
> > year ago.  I was hoping there was a package available premodified :)

Considering how often this comes up, it sounds like this needs to be done.
I can't contribute back the code I worked on because it belongs to
LucasArts.  However, I've been curious how much easier it might be to
retrace my steps given the newer, simpler, more re-entrant Lua 4.0 as a
starting point.  I used a dash of C++ here and there to make different
"threads" share variables by making the right parts of the class
static... Such mods would not be the type of thing that could easily be
rolled into stock C-only Lua, and in my mind there's no reason they should be
since this is a fairly specialized requirement (though it DOES seem common
among game developers).  However, an available patch that converts Lua for
this purpose would be good to have.  I would like to work on this, but my
free time for projects such as this is very slim... I'm not using Lua
day-to-day now and my personal life is a lot more cluttered.  That said,
I'll at least take a look when I get a chance and maybe draw up some
pseudo-directions for what needs to be done.

> well.. that (might) be usefull, but I think that depends on wether the
> modifications are "maintainable" (as far as I can "see", the current
> Monkey Island 4 demo still uses Lua 3.1 alpha, so they might have
> "trouble" upgrading to a newer lua because of the deep modifications
> they made).

Yes and no... I was the lead programmer on MI4 before I left.  They might
have trouble upgrading, but then again they have no reason to... The
version of Lua that they have handles the cooperative multitasking AND
serialization of Lua's internal data structures and of user-types
as well.  They are more interested in getting a game out than in having a
fresh, clean implementation of Lua 4.0 to program in; it's hard enough to
get a game out when you don't go breaking things that work fine.  =)

> > I think I can get away with manipulating the lua-state through C++
> > code, and wouldn't need to modify any of that?
> 
> I don't know (yet).

I'll take a look and tell you what I can.  =)


Bret
-- 
Bret Mogilefsky  ** mogul@playstation.sony.com **  Programmer, SCEA R&D