2.1 System structure

The instrument is the Processing sketch Swarm_Synth_V/ (16 tabs). The flocking logic knows nothing about drawing or sound; sound and visuals only read the swarm's state. No external Processing library is needed: the sketch has its own synthesizer and reads MIDI through Java's own javax.sound.midi.

File	Role
`Swarm_Synth_V.pde`	Main: modes (free play, score preview, render, atlas), the step loop, keys P / V / F / Shift+A / Shift+B
`Boid.pde`, `Flock.pde`	Pure flocking logic, 8 parameters, resolution scaling, torus distance
`SwarmMetrics.pde`	Whole-swarm measures, flock detection and flock identity over time
`SwarmEvents.pde`	Encounters between individual boids; flocks crossing the beat grid
`SoundEngine.pde`	Decides what to play: flock voices (macro), encounter notes (micro), pings, beat hits
`Synth.pde`	Makes the samples: 4 drone slots × 4 partials, one-shot notes, sine hits for the beat, limiter
`AudioOut.pde`	Speakers in real time; WAV writer for renders
`Score.pde`	Reads and plays a score (any `.txt` in `data/`)
`ScoreRecorder.pde`	Writes free play down as a simplified score (Shift+R)
`VideoRecorder.pde`	Offline render to mp4 via ffmpeg
`Atlas.pde`	Sound atlas: measures pattern, sound and feeling over 64 settings
`VisualEngine.pde`	Draws into the stage image (boids, sliders, overlay, HUD)
`BeatAtlas.pde`	Beat atlas: measures the beat over speed, max force and grid
`InputManager.pde`	Keyboard and mouse control
`Midi.pde`	MIDI controllers: a mapping file per device, pick-up, button lights, the controller map on screen

Every simulation step lasts exactly 1/60 s and produces exactly one audio block of 800 samples (48 kHz):

score.apply(t)        // score cues move the parameters
flock.update()        // the swarm moves
metrics.compute()     // whole swarm + flocks + identity
events.compute()      // encounters
events.computeBeats() // flocks crossing the beat grid
sound.update()        // flock voices, notes, pings, beat hits -> synth
synth.renderBlock()   // 800 samples

In real time the sound card paces this loop (the sketch waits until the audio buffer needs the next block). In a render, nothing is real time: steps run as fast as the computer can, and the result is identical every time.