Lua for wavetables

[baconpaul]

So if you give me

s (power of two samples) n (number of tables) f(n) -> float[s] (function to generate table n)

I can easily make a wavetable

and that sounds like a pretty easy thing to do with our lua evaluator

slightly different ui and storage strategy that formula modulator but most of what we have will carry over (which is why i named the gui classes LuaBlah not FormulaBlah).

[mkruselj]

For inspiration in what sort of functionality to add:

Hive Wavetables.zip

[SpotlightKid]

The Waldorf Microwave (I/II) also had an interesting way of generating Wavetables on the fly. You had to write a Wavtable program in a assembly-like language and then convert that into a Sysex-File, which you then sent to the synth.

I wrote a Python re-implementation of that converter ages ago. The actual calculation of the wavetable program happens in the hardware, though:

https://github.com/SpotlightKid/upaw2/blob/master/upaw.description

[baconpaul]

Gonna bounce this out of 1.2 again and deactivate it in the nightly

[nuoun]

So the wavetable script editor has been re-enabled in the Nightly builds for a while and I've been slowly working on it, so far #7674, #7680, #7687, #7755, #7764 and #7767 have been merged which refactor the code, make UI changes, add window tearout, implement the prelude for WTSE and some more and things are slowly coming together. I had a much longer writeup ready which I could still post if there is interest in some of the concepts and ideas and possible side projects for the future but I'll try to keep this short and limit this post to priority here which is to try and figure out what is needed to get this component ready for release.

So I will add a (likely incomplete) list of issues that still need work in the next post, but a lot of this is to just test and periodically ask if stuff makes sense or what needs improving and I would of course much appreciate feedback on this. Paul brought up two things on a previous PR which I'll mention here:

1. Window tear out, this currently works different for the WTSE, in formula the editor switches to the next LFO when a different LFO that has formula active gets selected and the WTSE does not do this even when another WT oscillator gets selected. I don't think this is a big issue, maybe a QoL thing at best and I'm not sure how this is handled in the GUI code right now. Other than that, the torn out window just stays open when the VCO gets changed and I think that is in line with how other torn out windows behave.

2. Accessibility, this needs both improvements and testing, the main issue I see now is that the graph's current frame numberfield is probably not helpful since accessibility should be disable on that entire component anyway so it should also skip over that UI element. Then it needs more testing but it probably makes sense to do that after we decide if this layout is final and/or if there is more to add.

So TL;DR, this project is being worked on and feel free to discuss, suggest, critique, help test, get involved, etc. (But really Shortcircuit could use more help so if you're looking for a project please focus on that!)

[nuoun]

Outstanding issues (WIP):

Code

• Add formula style init function
• Bail out of generate loop on Lua error
• Cancel button during generate
• Rename Lua variables and rename config table to wt in default script
• Add CI test for WTSE Prelude

UI

• Make mouse drag on the graph adjust sensitivity based on wavetable size
• Add menu links to manual on UI elements
• Discuss and ensure proper torn out window functionality

WTSE Prelude

• Add table versions of envelope, slew limiter, a simple compressor, etc
• Fourier series coefficients for common waveshapes
• More (numpy/matlab inspired) math functions

Accessibility

• Ensure proper naming and correct tab order of buttons
• Disable accessibility navigation on graph button
• Testing

Documentation

• Manual section

Tutorial and examples

• Basic tutorial that goes over wavetable concepts
• Tutorial that demonstrates various concepts like windowing, normalization, envelope, etc
• Additive synthesis examples with modulation over frames (e.g. types of FM/AM)
• PolyBLEP examples with modulation (e.g. PWM, phase modulation, phase distortion)
• Some other bandlimited synthesis methods (e.g. padsynth, BP resonator)

Bugfixes

• Fix graph not following onSkinChanged()
• More testing!