andromeda: A JavaScript repository from benji6

Andromeda is a pluggable digital audio workstation built on open web technologies

Plugin API

NB this API should be considered pre-alpha

EffectPlugin should be a constructor or factory function which is newed up with an object with the following props:

audioContext - instanceof AudioContext reference to the audioContext instance used by Andromeda
bpm - Number - current bpm

new EffectPlugin({ audioContext, bpm });

effectPlugin instances should then expose the following API:

connnect - Function - required method - to be implemented in the same manner as AudioNode.connect
destination - AudioNode | AudioParam - required property - an unchanging reference to an object which is a valid argument for AudioNode.connect
disconnect - Function - required method - to be implemented in the same manner as AudioNode.disconnect
render - Function - required method - called with a DOM element when the user wishes to view and possibly edit parameters in theplugin
setBpm - Function | undefined - optional method - called with a number representing the global bpm whenever it changes.

InstrumentPlugin should be a constructor or factory function which is newed up with an object with the following props:

audioContext - instanceof AudioContext reference to the audioContext instance used by Andromeda
bpm - Number - current bpm

new InstrumentPlugin({ audioContext, bpm });

instrumentPlugin instances should then expose the following API:

connnect - Function - required method - to be implemented in the same manner as AudioNode.connect
disconnect - Function - required method - to be implemented in the same manner as AudioNode.disconnect
noteStart - Function | undefined - optional method - called with a note object (see specification below). If available then controllers will be able to control this plugin
notesStart - Function | undefined - optional method - called with an array of note objects (see specification below). If unavailable controllers will attempt to call noteStart for each noteObj. Some plugin implementations may have performance benefits to batching the starting of notes.
noteStop - Function | undefined - optional method - called with the id of the note to stop. If available then controllers will be able to stop notes which are currently playing
noteModify - Function | undefined - optional method - called with a note object (see specification below). If available then controllers will be able to modify notes which are currently playing
render - Function - required method - called with a DOM element when user wishes to view and possibly modify parameters within the plugin
setBpm - Function | undefined - optional method - called with a number representing the global bpm whenever it changes.

Instrument plugins receive note objects which have the following properties:

frequency - Number - frequency in Hz of the note
gain - Number - gain of the note using the same basis as GainNode
id - String - unique id for this note which is essential for keeping track of which notes are playing and which are to be stopped
startTime - Number | undefined - optional property, if specified it is the time at which the note is to be started measured on the same basis as audioContext.currentTime, if not specified the note is expected to start immediately
stopTime - Number | undefined - optional property, if specified it is the time at which the note is to be stopped measured on the same basis as audioContext.currentTime, if not specified the note is expected to stop immediately