[GD-General] worker threads, level loading and progress bars

[<cas...@ya...>]

Hi,
to display a progress bar during the level loads, I've always used somekind
of callback mechanism, or a simple 'DoWork' function that performs a little
part of the work in each call and returns a special value when the work has
been finished. Those approaches worked ok, but the progress of the bar
wasn't smooth and the resulting code was not very clean:

int DoWork( int prev_step ) {
    if( prev_step==0 ) {
        "do some work"
        return ++prev_step;
    }
    else if( prev_step==1 ) {
        ...
    }
    ...
    else return finish_step;
}

I've been thinking about moving to a multithreaded approach. This worked
nicely until I tried to load textures, that of course didn't work because I
had to create a new rendering context for the new thread. My system and
specially the render was not designed with multithreading in mind, so I've
noticed that this approach would need many changes in my current design.
(creating multiple rendering context, locking and unlocking the render,
etc.).

Loading and uploading textures is almost half of the job, so unless I change
my architecture, the threaded approach doesn't seem very usefull, since I
still have to use the previous dirty work partition.

Instead of using multiple threads I could also try to use the current
method, but cleanly. For example by using an abstract job class, and a job
queue that manages and process the pending jobs. Decomposing all the work in
simple jobs, childs of the base job class and created by the job queue like
in a parametrized factory. Queueing the jobs at the beginning and processing
them secuentially on each 'DoWork' call.

But before doing so, I would like to know what other people are doing.

Thanks in advance,


Ignacio Castaño
cas...@ya...

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