SWEyeball Saga

Eye 11 adds idle wander: when the mouse isn’t being followed, the pupils drift on their own using Perlin noise — a smooth, continuous random function that produces natural-looking motion instead of jumpy randomness. Each eye has its own private noise seed, so they wander independently even with identical settings. This is the default behavior on launch; Follow mode overrides it.

Big Idea 1 — Why Perlin Noise Beats random()

Calling random() every frame produces white noise — each value is completely unrelated to the last. Pupils would teleport around rather than drift. Perlin noise is smooth: neighboring values in the noise field are always close to each other, so the output changes gradually over time. The eye wanders rather than twitches. p5.js makes this easy: noise(t) returns a smooth value in [0, 1] as t advances by small steps each frame.

Big Idea 2 — Two-Channel Cartesian Noise

A common mistake is to use one noise channel and treat its output as a radius, then pick a random angle. That drives the pupil back and forth through the center, giving a pendulum feel rather than a 2-D wander. Instead, lookingAround() samples two independent channels — one for X displacement, one for Y — so the pupil can roam anywhere in 2-D space smoothly. The two channels are sampled at different offsets in the noise field to ensure they have no correlation.

Big Idea 3 — Separating Amplitude from Speed

The lookingAround(strength) parameter controls how far the pupil travels (0 = centered, 1 = full sclera-edge travel). A separate instance property, noiseSpeed, controls how fast the wandering changes per frame. These two parameters are independent because they produce completely different personalities:

LOOK_STRENGTH	noiseSpeed	Character	Feels like…
0.8	0.002	Wide & slow	Dreamy, sleepy, half-awake
0.8	0.005	Wide & relaxed	Default — naturally curious
0.8	0.015	Wide & quick	Alert, excited, overstimulated
0.3	0.005	Tight & relaxed	Subtle, barely-moving gaze
0.3	0.02	Tight & fast	Nervous, darting, anxious
1.0	0.003	Maximum & slow	Dramatic, theatrical roaming
0.5	0.008	Medium	Balanced, focused but wandering

Big Idea 4 — Priority Chains and Modes

All three animation modes — drag, Follow, and lookingAround — coexist because draw() enforces a simple priority chain each frame:

1. Drag is highest priority. If the user is dragging a pupil, handleMouseDragged() has already moved it, and the other modes are skipped.
2. Follow ON — pupils rotate to face the cursor. Track ON gives a shared midpoint angle (perfectly in sync); Track OFF lets each eye compute its own angle (natural vergence / “wonky” mode).
3. lookingAround — the idle default. Fires when Follow is OFF. Track ON mirrors the left eye’s noise output to the right for synchronized wandering; Track OFF lets each eye follow its own unique noise path.

The sketch doesn’t need to manage conflicts — it just runs the chain top-to-bottom every frame and the first matching condition wins.

Big Idea 5 — Procedural Animation and Emergent Behavior

Nobody hand-animated these eyes. The wandering is procedural: generated from a mathematical rule (Perlin noise) rather than a keyframe sequence. And because each eye has a different noise seed, their independent wandering emerges into something that looks like two creatures sharing a space, occasionally glancing toward each other, occasionally apart — all from about ten lines of code.