// PIXEL WALLS — every particle carries one texel of input0; the grid
// pulls apart down the centre seam into two facing walls on the beat,
// each half keeping its own slice of picture, then breathes back flat.
{
    name: "Pixel Walls"
    engine: "particles"
    mode: "image"
    seed: 158
    input0: "test"

    count: 14400
    spread: 6.0
    size: 0.085
    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: "GAP", bind: "p0", default: 0.5},
        {name: "SPLIT", bind: "p1", default: 0.5},
        {name: "DEPTH", 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 * (0.25 + 1.5*p2)", levels: 2}
    ]

    // THE LOOK LIVES HERE: fx_center is the whole motion program — the
    // flat HOME grid position is blended against a two-wall TARGET by a
    // beat-driven breathing envelope. 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 u = gx / w - 0.5
            let v = 0.5 - gy / w
            let side = step(0.0, u) * 2.0 - 1.0
            let gap = spread * (0.5 + 0.9 * self.user.x)
            let rate = 0.3 + 1.4 * self.user.y
            // BOUNDED BEAT. One cosine every 8/rate beats, so wrapping
            // the rate-scaled beat count at 8 is the SAME phase — just
            // taken on a small number. `beat` is the song clock and does
            // not start at zero; multiplying a dial straight into it made
            // the split shimmer and jump on a deck cued hours into a set.
            let bph = modf(self.time_beat.y * rate, 8.0)
            let breathe = 0.5 - 0.5 * cos(bph * 0.7853982)
            let home = vec3(u * spread * 1.2, v * spread * 1.2, 0.0)
            let curve = (0.5 - abs(u)) * spread * 0.6 * self.user.z
            let wall = vec3(side * gap, v * spread * 1.3, curve)
            return home.mix(wall, breathe)
        }
    }
}