Triggers extension

[Trinitou]

Already discussed the idea for an trigger action extension in #222.

I came to the conclusion that a modified version of the params extension might be the best way to go about it so here it is a first proposal.

[Trinitou]

Some things I'm not totally sure about yet so input/discussion is very welcome:

• Not totally sure whether the request_flush mechanism is needed for trigger actions.
• Same goes for the cookie mechanism.
• First I thought that sample-accurate action triggering isn't needed as note-on messages might already do the job. But the more I think about it the more I can see that there is a place for sample-accuracy here as well.
  • (Also actions that are too CPU-heavy for sample-accuracy just shouldn't have the CLAP_ACTION_IS_AUTOMATABLE flag set and might happily ignore the sample offset information.)
  • Also in the future, Bitwig modulators could trigger sample-accurate plugin actions (with the modulation value crossing 0.0 or 0.5)
• I don't know yet of any DAW / plugin that has such a trigger action functionality so is this extension already relevant? And even per-voice? Otherwise one has to start. And at least I already can imagine many great use-cases 😃
• As mentioned here, it might be desirable to have a set of standard action IDs, like e.g. for something like "initialize current patch" ...

[abique]

I quickly went through and this is confusing. It seems that you are mixing together two different goals:

• engine trigger event, like you may want a trigger for an envelope; this is engine side, audio-thread
• user interface actions, which may have an icon in a toolbar, be bound to shortcut, have a localized display name, a tooltip etc... and basically trigger code on the GUI (main thread)

To me it seems that you are mixing GUI and DSP.

[Trinitou]

I quickly went through and this is confusing. It seems that you are mixing together two different goals:

• engine trigger event, like you may want a trigger for an envelope; this is engine side, audio-thread
• user interface actions, which may have an icon in a toolbar, be bound to shortcut, have a localized display name, a tooltip etc... and basically trigger code on the GUI (main thread)

To me it seems that you are mixing GUI and DSP.

I hope I could clear things up a bit. Now I went for the trigger event aspect first. For the other thing, I'll probably create a separate extension pull request.

[Trinitou]

Also I took out the "enabled" flag for triggers as it should be added to parameters as well then. But this is a completely different topic. Started a new discussion (#234).

[abique]

Thank you for your changes, we're almost there. 👍

[abique]

I think it is good as it is, I will merge the PR into the next branch and there might be more discussions about it later.

Thank you very much @Trinitou !