[SDL] Using timers for simulation
slouken at devolution.com
Sun Oct 14 15:12:01 PDT 2001
> I have interactive virtual world simulation work
> in progress. Currently I have two threads:
> - The main thread sits in loop rendering scene and
> polling inputs
The main thread should have a delay in it somewhere to allow the OS
to task switch to your simulation thread.
> - Before going to that loop I start timer which
> is run at regular intervals. It updates world
> simulation (objects positions and rotations are
> updated). It also processes input events so that
> if control key is being held down, that control
> is applied.
You should probably run the simulation in a separate thread directly,
synchronizing with the main thread. The timer code works, but is
more suited for small tasks than performing full simulation or doing
> I am not exactly sure how should I use timers. At the moment
> I have single SDL_AddTimer(), and that's it. How should I
> make changes to the timer update interval?
The return value of the timer function is the duration of the next
> Also, is the timer resolution still 'only 10ms', or can I
> actually get 'best resolution available' and maybe ask what
> is the resolution?
Nope, the 10ms number is a limitation of the multi-tasking slice
time of most current non-realtime operating systems.
-Sam Lantinga, Software Engineer, Blizzard Entertainment
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