// PIXEL HOP — every particle carries one texel of input0 and hops from
// its home cell to a freshly hashed spot every few beats, arcing up and
// settling back down — a slower, weightier cousin of the jitter shuffle.
{
    name: "Pixel Hop"
    engine: "particles"
    mode: "image"
    seed: 163
    input0: "test"

    count: 12100
    spread: 6.0
    size: 0.09
    rate: 0.0

    beat_pulse: "0.4 * (0.2 + 1.6*p0)"
    beat_rate: 1.0
    // PERFORMANCE DIALS — mid-knob = the stock look, exact.
    p0: 0.5  p1: 0.5  p2: 0.5
    dials: [
        {name: "DISTANCE", bind: "p0", default: 0.5},
        {name: "HANG", bind: "p1", default: 0.5},
        {name: "ARC", bind: "p2", default: 0.5}
    ]

    color_bg: #x050508
    color_a: #xffffff
    color_b: #xffffff
    color_c: #xffffff

    cam_dist: 7.5
    cam_height: 0.0
    cam_orbit: 0.0
    fog: 0.0

    stages: [
        {kind: "bloom", threshold: 0.55, strength: 1.1, levels: 2}
    ]

    // THE LOOK LIVES HERE: fx_center is the whole motion program. The
    // hop event is QUANTISED on floor(beat / beats-per-hop) — never the
    // raw clock — so every particle holds its landing spot for the whole
    // hang window before the next hash fires. Params: mode/id/dir/t01/cyc/r0/r1.
    shader: draw.DrawVjFxParticles {
        fx_center: fn(mode: float, id: float, dir: vec3, t01: float, cyc: float, r0: float, r1: float) -> vec3 {
            let spread = self.shape.y
            let w = self.shape.w
            let gx = modf(id, w)
            let gy = floor(id / w)
            let home = vec3((gx / w - 0.5) * spread * 1.2, (0.5 - gy / w) * spread * 1.2, 0.0)
            let beats_per_hop = 2.0 + 6.0 * clamp(self.user.y, 0.0, 1.0)
            let hop_i = floor(self.time_beat.y / beats_per_hop)
            let phase = fract(self.time_beat.y / beats_per_hop)
            let hx = fract(sin(id * 17.13 + hop_i * 41.7) * 39812.51)
            let hy = fract(sin(id * 5.37 + hop_i * 91.3) * 27431.9)
            let dist = spread * (0.1 + 0.5 * self.user.x)
            let target = home + (vec3(hx, hy, 0.0) - vec3(0.5, 0.5, 0.0)) * 2.0 * dist
            let settle = smoothstep(0.0, 0.35, phase)
            let pos = home.mix(target, settle)
            let arc = spread * (0.05 + 0.35 * self.user.z) * sin(clamp(phase, 0.0, 1.0) * 3.14159265)
            return pos + vec3(0.0, arc, 0.0)
        }
    }
}