Timeline and beats callbacks

[nerdp]

Hello! There is a little issue I wanna ask about. I'm subscribing on a Beat markers event, but because signals are fired only when _process in the game is called I'm getting a lag between an actual music beat and event. And that really troubles me. So the question - Is there some specific reason why signals are handled this way but not called right in the moment Fmod sends events?
Thanks!

[CedNaru]

Hi.
It was quite a while since that part was done so I'm not sure anymore.
I think the main reason was that we wanted the signals to be emitted by Godot main thread. As non-deferred signals are immediately calling the subscribers functions, if we were to call those signals from another thread, they would risk running at the same time as the main thread which could result in Data Race.

At the same time, we weren't knowledgeable enough about both Godot and the FMOD API so I guess we were too safe about that. But now that I checking that code again, I feel like it was unecessary.
You even have an option so Fmod triggers callback in a deferred way, just like you can defer Godot signals.

I guess I can make the change to emit the signals immediately instead of caching them for the next _process() call but it would be the responsibility of the user to be sure that the functions called by the signals are thread-safe.
Maybe I could add a parameter so you can set whether or not a signal is emitted immediately or not but that would overlap with the FMOD setting.

For reference:
https://fmod.com/resources/documentation-api?version=2.00&page=studio-guide.html#event-callbacks

Why is your opinion on that?

[nerdp]

I guess I can make the change to emit the signals immediately instead of caching them
It would be great!

Maybe I could add a parameter so you can set whether or not a signal is emitted immediately or not but that would overlap with the FMOD setting.
I'm not sure it's really necessary and it can lead to a confusion. Probably it would be enough to mention it in readme and provide a link on Fmod docs. Or mb adding a little descriptions to FMOD_STUDIO_INIT_DEFERRED_CALLBACKS and FMOD_STUDIO_INIT_SYNCHRONOUS_UPDATE flags in gd script file