Implement Edges

[Kautenja]

Implement the Edges module.

Some notes:

• [ ] the faceplace needs to be replaced (the font is wrong)
• the sequencer functionality is not implemented
  • IMO, implementing this is not worthwhile for the software module
• [ ] I cannot figure out how the sine bitcrusher functionality works
  • the manual mentions it and the code has CV control for it, but how this is controlled by the interface is neither documented, nor easily discernible from the code.
• the square wave generator is a DSP implementation based on the VCO from the Fundamental modules
  • the square wave generator on edges uses the AVR library and appears to require hardware integration (timers)
• the digital oscillator is reimplemented from the eurorack code
  • hacking the eurorack code to integrate directly with VCV resulted in too many changes to the underlying frameworks like avrlibx
• the module is designed to run at 48KHz, but I've added some logic to support all the sample rates in VCV rack
  • the square waves use the standard method from the Fundamental VCO
  • the digital oscillator uses the built-in interpolation functionality in the eurorack code and scales the phase interval to adjust the sample rate

[AndrewBelt]

Unfortunately this is further from release quality than I expected, and I've already reached my code review time window on this, so perhaps we can continue review in 2021 or 2022. Of course, you are welcome to develop your software as a fork of Audible Instruments.

• At first glance it doesn't sound like Mutable Edges. I've never owned Edges, but demo videos seem to be very different from this. Do you own Edges? I obviously can't accept a clone of hardware written someone who's never used the hardware.
• The pulse oscillators are fully aliased, while they have no aliasing at all on Mutable Edges.
• There's too much state information in the Edges class. For example, why does is_gate1_open need to be stored between process() calls?
• If you're going to make up your own type uint24_t, call it something else. Also, that isn't a floating point type. That's fixed point. What are you using fixed-point for?
• This module isn't polyphonic... So why use simd::float_4??
• The sequencer of Edges is a big part of its functionality. We can't leave that out.
• etc etc