// DYE RELIEF — a SIM FIELD consumed by ANOTHER engine: the document
// declares a fluid field in `fields:` and binds its dye texture as
// input0 via "field:dye"; the heightmap engine then EXTRUDES the flowing
// ink (tex_displace) — kick splats raise mountains that melt and drift
// with the fluid. Pattern taught here: fields:[...] + input0: "field:<n>"
// makes any texture-input effect a sim consumer.
{
    name: "Dye Relief"
    engine: "heightmap"
    seed: 7

    res: 150
    size: 26.0
    height: 5.5
    scroll: 0.0
    tex_displace: 0.85

    fields: [
        {
            name: "dye"
            kind: "fluid"
            res: 128
            iters: 16
            force: 2.2
            dissipation: 0.10
            swirl: 0.4
            splat: "(1.5 + pulse * 0.7) * (0.2 + 1.6*p0)"
            dye_fade: 0.14
            radius: 0.09
        }
    ]
    input0: "field:dye"

    beat_pulse: "0.35 * (0.2 + 1.6*p1)"
    beat_rate: 0.5
    // PERFORMANCE DIALS — mid-knob = the stock look, exact.
    p0: 0.5  p1: 0.5  p2: 0.5
    dials: [
        {name: "SPLAT", bind: "p0", default: 0.5},
        {name: "PUMP", bind: "p1", default: 0.5},
        {name: "GLOW", bind: "p2", default: 0.5}
    ]

    color_bg: #x080611
    color_a: #x3a2a8f
    color_b: #xff5ad0
    color_c: #xc8f0ff

    cam_orbit: 0.0
    cam_height: 6.5
    cam_dist: 12.5
    fog: 0.035
    glow: "1.2 * (0.25 + 1.5*p2)"

    stages: [
        {kind: "bloom", threshold: 0.5, strength: 1.2, levels: 3}
    ]

    // 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 = height 0..1, attr = (slope, grid line, uv.x, uv.y).
    // 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.DrawVjFxTerrain {
        fx_color: fn(t: float, attr: vec4, content: vec4, cmix: float) -> vec4 {
            let grad = self.col_a.mix(self.col_b, t).xyz
            let beat_glow = 1.0 + self.time_beat.w * 1.1
            let drape = content.xyz * (0.42 + 0.85 * attr.x)
                * (1.0 + self.time_beat.w * 0.30)
            let surface = (grad * 0.30 * attr.x)
                .mix(drape, clamp(cmix * 1.25, 0.0, 1.0))
            let gline = grad.mix(content.xyz * 1.3, cmix * 0.55)
            let neon = gline * attr.y * beat_glow * 1.6
                + self.col_c.xyz * attr.y * t * 0.6
            return vec4(surface + neon, 1.0)
        }
    }
}