// PIXEL BURST — every particle carries one texel of input0 and explodes
// outward from the plane's centre on a saw-phase clock: each cycle snaps
// open fast, drags to a stop, then resets and fires again.
{
    name: "Pixel Burst"
    engine: "particles"
    mode: "image"
    seed: 157
    input0: "test"

    count: 12000
    spread: 6.0
    size: 0.09
    rate: 0.35

    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: "SPEED", bind: "p0", default: 0.5},
        {name: "SPIN", bind: "p1", default: 0.5},
        {name: "HANG", 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: "feedback", amount: "0.35 + 0.3*p2", zoom: 1.01, rotate: 0.0, dim: 0.94},
        {kind: "bloom", threshold: 0.55, strength: "1.1 * (0.25 + 1.5*p0)", levels: 2}
    ]

    // THE LOOK LIVES HERE: fx_center is the whole motion program — a
    // fresh saw-phase explosion every respawn cycle (the doc's `rate`
    // field paces the cycle), drag-eased outward from the plane's centre
    // along each particle's own random direction seed.
    // Params: mode/id/dir/t01/cyc/r0/r1 — see CONTRACT.md "particles".
    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 speed = spread * (0.6 + 1.4 * self.user.x)
            let k = 1.0 + 4.0 * (1.0 - clamp(self.user.z, 0.0, 1.0))
            let drag = (1.0 - exp(0.0 - k * t01)) / k
            let pos = dir * speed * drag * (0.6 + 0.6 * r1)
            let spin = self.user.y * 5.0
            let ang = spin * t01
            let cs = cos(ang)
            let sn = sin(ang)
            let x = pos.x * cs - pos.y * sn
            let y = pos.x * sn + pos.y * cs
            return vec3(x, y, pos.z)
        }
    }
}