// COPPER REEF — rasterbars reborn as 3D lacquered slabs: a stack of
// full-width copper bars sine-dancing and weaving in depth. Pattern
// taught: the choreography CROSSFADE — `mode` (sine) rolls into
// `mode_b` (curtain) and back on every bar via `p3: "0.5-0.5*cos(bar*
// tau)"` (curtain keeps each bar's side of the centre, so the morph
// never collapses the stack); `p0` pumps the dance amplitude with the
// bass and `p1` is the classic rasterbar thickness breath.
{
    name: "Copper Reef"
    engine: "copperbars"
    seed: 7

    bars: 22
    mode: "sine"
    mode_b: "curtain"
    width: 15.0
    span: 6.5
    thickness: 0.44
    depth: 1.3
    amplitude: 1.7
    weave: 1.3
    metal: 3.0

    beat_pulse: 0.6
    p0: "0.3 + 0.9*bass + 0.5*pulse"    // amplitude gain
    p1: "0.4 + 0.9*env(phase)"          // the thickness pump
    p3: "0.5 - 0.5*cos(bar*tau)"        // sine <-> curtain each bar

    // PERFORMANCE DIALS — DANCE/THICK are the engine's own p0/p1 levers
    // (touching one holds its binding above); GLOW routes p2.
    p2: 0.5
    dials: [
        {name: "DANCE", bind: "p0", default: 0.5},
        {name: "THICK", bind: "p1", default: 0.5},
        {name: "GLOW", bind: "p2", default: 0.5}
    ]

    color_bg: #x0a0708
    color_a: #xff9a3c      // copper core
    color_b: #x571f10      // lacquer edge
    color_c: #xffe8c0      // specular line

    cam_orbit: 0.045
    cam_fov: 50.0
    fog: 0.020
    glow: "1.1 * (0.25 + 1.5*p2)"

    stages: [
        {kind: "bloom", threshold: 0.55, strength: 1.0, levels: 3},
        {kind: "feedback", amount: "0.3 + 0.2*pulse", zoom: 1.004, dim: 0.95}
    ]

    // 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 = the bar gradient axis 0..1, attr = (id, aux, r0, r1).
    // 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.DrawVjFxCopper {
        fx_color: fn(t: float, attr: vec4, normal: vec3, wpos: vec3) -> vec4 {
            let band = pow(clamp(sin(t * 3.14159265), 0.0, 1.0), max(self.flow.z, 0.5))
            let base = self.col_b.mix(self.col_a, band)
            let sline = 1.0 - clamp(abs(t - 0.68) * 9.0, 0.0, 1.0)
            let spec = pow(sline, 3.0) * (0.5 + self.time_beat.w * 0.8)
            let vary = 0.85 + 0.30 * attr.z
            return vec4(base.xyz * vary + self.col_c.xyz * spec, 1.0)
        }
    }
}