// INK LOOM — a Victorian harmonograph drawing pale ink in the dark: one
// ribbon traces the damped pendulum sum, redrawn pen-first every 16 beats
// (grow: "loop"), and the FIGURE ITSELF morphs to a fresh coefficient set
// on the same 16-beat clock — it never draws the same rosette twice.
// Pattern taught: grow_beats aligned with morph_beats = each figure gets
// exactly one complete drawing before the loom re-threads.
{
    name: "Ink Loom"
    engine: "harmonograph"
    seed: 24

    segments: 1800
    strands: 1
    freq_x: 2.0
    freq_y: 3.0            // 2:3 — the classic rosette family
    freq_z: 1.0
    damping: 0.6
    detune: 0.05
    turns: 6.0
    width: 0.05
    morph_beats: 16

    grow: "loop"
    grow_beats: 16
    beat_pulse: 0.4
    p1: "0.35 * pulse"     // the nib presses harder on the beat

    // PERFORMANCE DIALS — all three are the engine's own p-levers:
    // DETUNE splays the pendulum ratios, WIDTH overrides the nib-press
    // binding above when touched, DEPTH pulls the figure into z.
    dials: [
        {name: "DETUNE", bind: "p0", default: 0.0},
        {name: "WIDTH", bind: "p1", default: 0.5},
        {name: "DEPTH", bind: "p2", default: 0.0}
    ]

    color_bg: #x05060d
    color_a: #xd8d0c0
    color_b: #x8090b8
    color_c: #xffffff

    cam_orbit: 0.06
    cam_dist: 5.2
    fog: 0.02
    glow: 1.1

    stages: [
        {kind: "feedback", amount: 0.55, zoom: 1.0, rotate: 0.0, dim: 0.955},
        {kind: "bloom", threshold: 0.45, strength: 1.1, levels: 2}
    ]

    // THE LOOK LIVES HERE. This block is not a reference to the
    // engine's shader — it IS the pixel math this effect runs.
    // Rewrite it and the effect looks different; everything else
    // (geometry, motion, the content coupling, the beat) keeps
    // working, because the block SUBCLASSES the engine shader.
    // Inputs: t = curve position 0..1, attr = (strand, t, rnd, side).
    // Signals: self.time_beat (time, beat, phase, pulse),
    // self.sig (bar, bpm, energy, dt), self.user (p0..p3),
    // self.col_a/b/c/bg, self.fog (density, glow, content, -).
    shader: draw.DrawVjFxHarmono {
        fx_color: fn(t: float, attr: vec4, normal: vec3, wpos: vec3) -> vec4 {
            let strand01 = self.geom.geom_uv.y
            let hue = fract(t * 0.85 + strand01 * 0.34 + self.user.w)
            return self.col_a.mix(self.col_b, hue)
        }
    }
}