How do I tell which iPlug2 parameter maps to which Faust parameter?

Faust
1

Hi! I’m trying to use iPlug2 to wrap an instrument I wrote in Faust into a VST3 plugin. I got it to make sound in the standalone build, but now I want to make a user interface for it. Is there a way to get a mapping of Faust parameter name to parameter index, somehow? As my plugin will include a lot of parameters I don’t want to just use trial and error…

More concretely, I want to know which index to use to eg. control the 0/partial gain parameter given this code:

tonalizer(freq, q) = _ <:
    vgroup("[0]H", band(0, freq / 2, q, vslider("h:[0]0/[0]partial gain", 0.5, 0.0, 1.0, 0.01))),
    vgroup("[1]F", band(1, freq, q, vslider("h:[1]1/[0]partial gain", 1, 0.0, 1.0, 0.01))),
    vgroup("[2]2", band(2, freq * 2, q, vslider("h:[2]2/[0]partial gain", 0.25, 0.0, 1.0, 0.01))),
    vgroup("[3]4", band(4, freq * 4, q, vslider("h:[3]4/[0]partial gain", 0.25, 0.0, 1.0, 0.01))),
    vgroup("[4]6", band(6, freq * 6, q, vslider("h:[4]6/[0]partial gain", 0.25, 0.0, 1.0, 0.01))),
    vgroup("[5]8", band(8, freq * 8, q, vslider("h:[5]8/[0]partial gain", 0.25, 0.0, 1.0, 0.01))),
    vgroup("[6]10", band(10, freq * 10, q, vslider("h:[6]10/[0]partial gain", 0.25, 0.0, 1.0, 0.01))),
    vgroup("[7]12", band(12, freq * 12, q, vslider("h:[7]12/[0]partial gain", 0.25, 0.0, 1.0, 0.01))),
    vgroup("[8]14", band(14, freq * 14, q, vslider("h:[8]14/[0]partial gain", 0.1, 0.0, 1.0, 0.01))),
    vgroup("[9]16", band(16, freq * 16, q, vslider("h:[9]16/[0]partial gain", 0.1, 0.0, 1.0, 0.01)))
    :> /(12);
2

So looks like the line mFaustProcessor.CreateIPlugParameters(this, 0, mFaustProcessor.NParams()) will set the param names from your Faust code. Then you can get the name from GetParam(int)->GetName() and do whatever you need with it to hook up controls to the right param number. mFaustProcessor.CreateIPlugParameters() can be called regardless of whether you are in the DSP or in the UI and does not depend on mFaustProcessor.Init() being called first.

The param names ignore any sort of hierarchy: A param named h:[0]0/[0]partial gain in Faust will just be partial gain in iPlug2 code. You will need to name your Faust params partial gain 0, partial gain 1, etc.