[Fluxus] wait?

[David Griffiths]

Hi Kassen,

On Fri, 2011-01-07 at 01:34 +0100, Kassen wrote:
> The thing is; I remembered there were ways to make scheme threads
> wait. What I would like to do is clear, then put a image or text on
> the screen, then actually render that for a frame, then continue
> parsing rather a lot of code that loads a fair amount of objects and
> textures. Essentially I want a "loading" screen at (re)compiling and I
> can't figure out a way to do that.
> 
> 
> It seems that the renderer is in the same thread that my code is in
> and so won't render before my code is done.

There are two things here. If you want to run a thread that blocks in
the background while another thread updates the screen with smooth
animation, then I think the answer is no - fluxus is single threaded (in
os terms). I think there are moves to add os level concurrency to
racket, but I haven't been keeping a close eye on developments there.

If you want to use racket threads to sequence execution so you can
display a loading screen first, then this should be possible. You can
use (sleep).

I've not needed to use threads for this purpose though, it's usually
sufficient to have a kind of state machine in operation - eg:

title screen ---> menu screen -----
                       ^           \
                       \           /
                        --- game <-

With each mode responsible for loading and setting itself up, as well as
cleaning itself up before entering a new mode. 

I can try and dig out a concrete example if you like.

cheers,

dave