Re: Game Integration

[Ignacio Castaño <castanyo@...>]

I don't think in term of scripts but in term of entities or actors. An actor
has a given state and that state may have an associated script. When the
actor enters the state it starts executing the script. The script may
contain a yield in its body, but usually, those yields are associated to
other events, for example:

play_anim()

sets an animation, and yields. When the animation ends the entity recieves
an event, that resumes the coroutine, and continues the execution of the
script.

In your case I would have an entity called 'mision_completion', that entity
will always execute the following script:

while ~mission_completed() do
    self:send_resume_event( 0.5 )
    yield()
end
self:get_game():end()


that is, it checks the mission completion status every 500 milliseconds and
does only end the game when the mission is completed.

I usually abreviate that using:

self:sleep( 0.5 )

that again, yields implicitely. This makes the code very readable and
intuitive because you just think about linear actions, and not about events
and message handlers.


Ignacio Castaño
castanyo@yahoo.es


Chris Brodie wrote:
> I'm still not following how this works with my code. Cooroutines seem to
execute within a single script if I read it correctly. A yield will return
control to a central loop also within the script. At what point does my code
start executing again so I actually do all my 'game' code?
>
> For example, when I call lua_dofile it blocks until execution has
completed(as far as I know). So when I'm say loading a level from my code
what I'm looking at doing architecturally is loading a lua file that places
all the entities(models etc) and sets up the mission loop, periodically the
main mission loop would need to check on a mission completion status.
>
> This is all fine so far but with a blocking lua_dofile the mission thread
will never return. My game graphics rendering\input\sound etc will never
take place. Is there a Yield() command in Lua that return from lua_dofile?
Then in my games main loop I can call some kind of lua_dofileResume() to
resume the scripts activity?
>
> Right now the only (ugly) way I can see this would work would be to have a
lua script that call my rendering engine to draw the graphics and do physics
\ gather input etc.
>
> Am I missing the whole point here? I found this C command 'lua_newthread'.
Why does this exist for? I can imagine that this might do half my job in
starting a blocking script in a thread but I'm not sure if this is the
intended use...
>
> Many thanks for your patience,
>
> Chris
>
>
> <Snippety Bits>
> > From: Nick Trout [mailto:nick@rockstarvancouver.com]
> > Subject: RE: Game Integration
> > I've been writing a Lua tutorial and there is a page on coroutines:
> > http://lua-users.org/wiki/CoroutinesTutorial
> >
> > Regards,
> > Nick
>
>
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