State recall in Bitwig

[519q]

Hi
I wonder how do I implement non-param data recall between engine disable/enable calls in Bitwig?
Now Bitwig dont call clap_plugin_state::save() on disable and ::load() on enable, it rather sends stored somewhere inside BW param values from prev session via audio que.
But I also have internal mod matrix that has values that I need to recall, and I dont want to put those inside param system.

Same issue would arise if I`d need to recall something like array of floats representing custom wt osc shape, or path to file etc

Thanks!

[defiantnerd]

You should not discard the values inbetween activation states.

Deactivated is just a state.

[baconpaul]

ooooh that is a good answer but: if bitwig deactivates you without a precautionary save on engine shutdown i think it is making a bold choice, at least.

[519q]

Did you call clap_host_state::mark_dirty()?

yes it was it, marked dirty it saves and loads

i thought it flips same bool when param change happens, seemed to follow from this comment:
// If a parameter value changes, then it is implicit that the state is dirty.
maybe it makes sense to notify user that non-param resources saved and recalled only after explicitly called make_dirty()?

Thanks!

[madah81pnz1]

For normal parameters it should work without mark_dirty(), but when wiggling parameters in the UI, you also need to send those back as events to the host, with e.g. CLAP_EVENT_IS_LIVE.

Otherwise it will be the same problem, only the plugin and its editor knows about the updated parameter value, but the host doesn't.

[519q]

Issue was in recalling data that not related to param sys, eg sample path. For that to work user have to call clap_host_state::mark_dirty().

"// If a parameter value changes, then it is implicit that the state is dirty."
Despite this comment, this 'implicit dirty' is different kind of dirty - it only saves param values inside Bitwig state, and then sends those back in audio loop using CLAP_EVENT_PARAM_VALUE messages. It DOES NOT call save() and load() at all in that case.
(I also figured that on vst3 side user have to call restartComponent() for the same effect)

And as you mentioned CLAP_EVENT_IS_LIVE, what exactly is that for? Comment says that that is to notify host about live event, but what that even means specifically? is it different from sending CLAP_EVENT_PARAM_GESTURE messages?

[defiantnerd]

CLAP_EVENT_IS_LIVE is for a host flagging events that are being played live from a user and not played from a MIDI track etc.

Purpose is to distinguish them for hardware plugins so they might omit sample accuracy for latency. This helps to get a snappier feeling.