// TRAIL ADD — additive feedback trails with one explicit decay dial: no
// hidden pulse/bar math driving the persistence, DECAY alone sets how
// long a frame lingers before it's gone.
{
    name: "Trail Add"
    engine: "screen"
    seed: 208
    input0: "test"

    speed: 1.0
    beat_pulse: 0.3
    beat_rate: 1.0
    bar_beats: 4
    glow: 1.0
    // PERFORMANCE DIALS — mid-knob = the stock look, exact.
    p0: 0.5  p1: 0.5  p2: 0.5
    dials: [
        {name: "DECAY", bind: "p0", default: 0.5},
        {name: "GLOW", bind: "p1", default: 0.5},
        {name: "SPIN", bind: "p2", default: 0.5}
    ]

    color_bg: #x03040a
    color_a: #x30ffd0
    color_b: #xff3a86
    color_c: #xfff0d0

    stages: [
        {kind: "feedback", amount: "0.35 + 0.6*p0", zoom: "1.006 + 0.02*p0",
         rotate: "(p2-0.5)*0.05", dim: "0.88 + 0.11*p0"}
    ]

    // THE LOOK LIVES HERE: fx_color hot-boosts the scene before the
    // feedback stage sees it — bright pixels burn extra hard so the
    // additive trail reads as a hot streak rather than a soft wash.
    // Inputs: uv, content = input0 at uv, cmix = pre-gated content
    // strength. 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.DrawVjFxScreen {
        fx_color: fn(uv: vec2, content: vec4, cmix: float) -> vec4 {
            let luma = dot(content.xyz, vec3(0.299, 0.587, 0.114))
            let boost = 1.0 + 1.2 * clamp(self.user.y, 0.0, 1.0)
            let hot = vec3(1.0, 1.0, 1.0) * pow(clamp(luma, 0.0, 1.0), 4.0) * clamp(self.user.y, 0.0, 1.0) * 0.4
            let rgb = content.xyz * boost + hot
            return vec4(clamp(rgb, vec3(0.0, 0.0, 0.0), vec3(1.0, 1.0, 1.0)), 1.0)
        }
    }
}