NOTE: This was a component of Alda 1.x. It is no longer in use.
A Clojure implementation of an Alda sound engine.
The alda.sound namespace functions as a library focused on playing a fully
realized Alda score map.
The alda.sound namespace handles the implementation details of playing the
score.
There is an "audio type" abstraction which refers to different ways to generate
audio, e.g. MIDI, waveform synthesis, samples, etc. Adding a new audio type is
as simple as providing an implementation for each of the multimethods in this
namespace, i.e. set-up-audio-type!, refresh-audio-type!,
tear-down-audio-type!, start-event! and stop-event!.
The play! function handles playing an entire Alda score. It does this by using
a Sequencer to schedule all of the note events to be played,
and a Synthesizer to play them. The time that each event starts and
stops is determined by its :offset and :duration.
What happens, exactly, at the beginning and end of an event, is determined by
the start-event!/stop-event! implementations for each instrument type. For
example, for MIDI instruments, start-event! sets parameters such as volume and
panning and sends a MIDI note-on message at the beginning of the score plus
:offset milliseconds, and stop-event! sends a note-off message :duration
milliseconds later.
Copyright © 2012-2019 Dave Yarwood et al
Distributed under the Eclipse Public License version 1.0.