// PIXEL ORBIT — every particle carries one texel of input0 and circles a
// great circle whose axis is hashed per particle, so the picture scatters
// into a slow swarm of independent rings rather than one shared spin.
{
    name: "Pixel Orbit"
    engine: "particles"
    mode: "image"
    seed: 161
    input0: "test"

    count: 10000
    spread: 6.0
    size: 0.095
    rate: 0.0

    beat_pulse: "0.4 * (0.2 + 1.6*p1)"
    beat_rate: 1.0
    // PERFORMANCE DIALS — mid-knob = the stock look, exact.
    p0: 0.5  p1: 0.5  p2: 0.5
    dials: [
        {name: "ORBIT", bind: "p0", default: 0.5},
        {name: "SPEED", bind: "p1", default: 0.5},
        {name: "TILT", 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: "0.4 + 0.3*p1", zoom: 1.006, rotate: 0.0, dim: 0.95},
        {kind: "bloom", threshold: 0.55, strength: 1.15, levels: 2}
    ]

    // THE LOOK LIVES HERE: fx_center is the whole motion program — each
    // particle's own random direction seed (`dir`) becomes its orbit
    // AXIS, and a Rodrigues rotation spins a fixed radius vector around
    // it. Params: mode/id/dir/t01/cyc/r0/r1.
    shader: draw.DrawVjFxParticles {
        rot_axis: fn(v: vec3, axis: vec3, ang: float) -> vec3 {
            let c = cos(ang)
            let s = sin(ang)
            return v * c + cross(axis, v) * s + axis * (dot(axis, v) * (1.0 - c))
        }
        fx_center: fn(mode: float, id: float, dir: vec3, t01: float, cyc: float, r0: float, r1: float) -> vec3 {
            let spread = self.shape.y
            let axis = normalize(dir)
            let seedv = vec3(0.0, 1.0, 0.0)
            let perp = normalize(cross(axis, seedv) + vec3(0.0001, 0.0, 0.0))
            let radius = spread * (0.35 + 0.55 * r0) * (0.4 + 1.3 * self.user.x)
            let speed = 0.15 + 1.2 * self.user.y
            let ang = self.time_beat.x * speed * (0.5 + r1) + id * 0.017
            let p = self.rot_axis(perp * radius, axis, ang)
            let tilt = 0.3 * self.user.z
            return p + axis * sin(self.time_beat.x * 0.3 + id * 0.7) * radius * tilt
        }
    }
}