EasyVST

A VST Instrument Plug-In that connects to a remote Ruby process via DRb to process audio samples and MIDI messages.

Requirements

This project has only been tested on Mac OS X. The vst/Makefile will likely need modifications to build on other systems.

You will also need the VST3 SDK and a a compatible DAW that can use VSTs.

Using

To build the VST and start the server, copy the VST SDK into vst/vst3 and type:

$ rake

This will launch you into a interactive Ruby console where you can control the $music object that is exposed by DRb.

To change the music function, set $music.fn. Some examples:

# Play a square wave
$music.fn = SQUARE

# Play a square + sine wave
$music.fn = -> { e(SINE) * 0.5 - e(SQUARE) * 0.5 }

See the music_server.rb file for more functions and examples defined as constants at the top of the file.

Remote Server Protocol

A sample server is provided in music_server.rb. To implement a custom server, you must expose an object to the DRb service on port 9090 that supports the following methods:

#process(num_samples) -> Array<Float>

Synthesizes num_samples samples for audio playback. This function should return an array of num_samples floating point values.

#midi_note(status, note, velocity) -> void

Indicates that a MIDI note changed its status. The default server has logic to handle a single MIDI note being pressed at a time.

#midi_all_off -> void

Indicates that all MIDI messages have been stopped.

License

EasyVST is licensed under an MIT license and was created by Loren Segal in 2014. The files under vst/source were created from templates provided by the teragonaudio/XcodeVstTemplates project on GitHub.