GestVM
Introduction
GestVM implements a so-called "gesture synthesizer", sequenced and controlled via the Uxn Virtual machine.
A Gesture Synthesizer is an audio-rate control signal generator whose timing is managed by another audio-rate control signal generator, called a conductor.
Conceptually, a Gesture can be thought of as something between an automation curve and breakpoint line generator.
Overview of System
An instance of an Uxn VM is created inside of sndkit, and a ROM is loaded. One more signal generators, called nodes, are then created, which can concurrently evaluate the Uxn VM with different starting memory positions. Each node implements a gesture synthesizer, whose state can be controlled via an Uxn virtual output device. For input, a node takes in a "conductor" signal, which is periodic rising ramp signal commonly referred as a phasor.
The synthesized gesture signal produced by nodes can then be used to modulate parameters in other sndkit nodes. A common parameter is the pitch of an oscillator.
Compilation
To use GestVM, first compile and install sndkit. Sndkit can be found on github or sourcehut.
Running make will build the gestvm binary (the sndkit
LIL interpreter with added gestvm words), as well
as a modified version of the uxnasm utility used to
assemble Uxn ROMs.
Running Examples
Examples can be found in the "examples" folder. Running
the script ./render.sh will compile the Uxn
programs and then render sndkit program which
loads the ROM and generates the WAV files.
Each example comes with a Uxn program (".tal" extension) and a sndkit patch (".lil" extension). From these a ROM file (".rom") and WAV audio file (".wav") are generated.
sequence is a program which produces a sequence that
gets proportionally faster every time it repeats. It
starts with eigth notes, then triplets, then sixteenths,
etc. Eventually it will hit a limit and start slowing
down again.
skew is a program which tests out a concept called
temporal skewing, a process which allows tempo to be
locally warped without adding or subtracting time overall.
This example has a phrase which uses an exponential
temporal skewing curve to perform an accelerando over
9 beats.
weight is a program which tests out a concept called
temporal weight, a process which gives the notes themselves
to warp global tempo. This program produces a lyrical
melody that uses weight to programatically
shape the phrasing.