// SYNTHWAVE GRID — the retro terrain flythrough. The grid mesh never
// changes; the vertex shader displaces it with scrolling fbm and the pixel
// shader draws the neon wireframe. Pure fast path.
{
    name: "Synthwave Grid"
    engine: "heightmap"

    res: 130
    size: 34.0
    height: 2.6
    noise_scale: 0.14
    scroll: 3.0

    beat_pulse: "0.6 * (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: "PUMP", bind: "p0", default: 0.5},
        {name: "GLOW", bind: "p1", default: 0.5},
        {name: "FLARE", bind: "p2", default: 0.5}
    ]

    color_bg: #x0c0018
    color_a: #xff2cd8
    color_b: #x2cd8ff
    color_c: #xffffff

    cam_fov: 62.0
    fog: 0.05
    glow: "1.2 * (0.25 + 1.5*p1)"

    stages: [
        {kind: "bloom", threshold: "clamp(0.4 - (p2-0.5)*0.6, 0.02, 0.95)", strength: 1.6, 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)
        }
    }
}