// FLASH CRASH — the red-terminal panic. Cascades arm at bar boundaries
// (`cascade` chance per bar) and slam the walk downward for most of a bar
// with doubled volatility; the shader's panic wash (`p2`) floods the
// terminal red on every pulse while a cascade is running, and down-candles
// burn blood-red through the bloom. Pattern taught: the crash is CPU state
// (a beat-clocked cascade machine), the panic is shader state (uniform
// `cascade` + the p2 binding) — the two lock to the same bar.
{
    name: "Flash Crash"
    engine: "stockcharts"
    seed: 87

    candles: 96
    per_beat: 2
    vol: 2.2
    drift: -0.4
    spike: 3.0
    cascade: 0.65
    bar: 4
    ma: 10
    grid_x: 4
    grid_y: 8
    scan: 18
    width: 15
    height: 8

    beat_pulse: 0.8
    p0: "0.2 + 0.3*pulse"        // the whole board pumps
    p1: "0.5 + 0.9*pulse"        // crosshair panic
    p2: "0.25 + 0.45*pulse"      // red wash breathing on the beat

    // PERFORMANCE DIALS — the chart engine's own p-levers; touching one
    // holds its pulse binding above at a fixed level (PANIC full right =
    // the board drowns in red).
    dials: [
        {name: "GAIN", bind: "p0", default: 0.5},
        {name: "XHAIR", bind: "p1", default: 0.5},
        {name: "PANIC", bind: "p2", default: 0.5}
    ]

    color_bg: #x070102
    color_a: #x9aa89a
    color_b: #xff2333
    color_c: #xffffff

    cam_orbit: 0.0
    cam_fov: 40
    fog: 0.0
    glow: 1.25

    stages: [
        {kind: "bloom", threshold: 0.35, strength: 1.6, levels: 3},
        {kind: "feedback", amount: "0.30 + 0.25*pulse", zoom: 1.003, rotate: 0.0, dim: 0.93}
    ]

    // 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 = candle age 0..1, attr = (element class, age, up/down, move size).
    // 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.DrawVjFxCharts {
        fx_color: fn(t: float, attr: vec4, normal: vec3, wpos: vec3) -> vec4 {
            let class = attr.x
            if class < 0.5 {
                // Candle body: col_a up / col_b down, big moves burn.
                let base = self.col_b.mix(self.col_a, step(0.5, attr.z))
                let burn = 0.75 + attr.w * 0.7 + self.time_beat.w * (1.0 - t) * 0.6
                return vec4(base.xyz * burn, 1.0 - t * 0.55)
            }
            if class < 1.5 {
                let base = self.col_b.mix(self.col_a, step(0.5, attr.z))
                return vec4(base.xyz * 0.55, (1.0 - t * 0.55) * 0.8)
            }
            if class < 2.5 {
                return vec4(self.col_a.xyz * 0.16, 0.5)
            }
            if class < 3.5 {
                // Kept modest: the bloom stage amplifies this line, and an
                // over-gained crosshair blows out into a white bar.
                let g = 0.55 + self.user.y * 0.5 + self.time_beat.w * 0.25
                return vec4(self.col_c.xyz * g, 0.8)
            }
            if class < 4.5 {
                return vec4(self.col_c.xyz * 0.5 + self.col_a.xyz * 0.4, 0.85)
            }
            return vec4(self.col_a.xyz * 0.6, 0.9)
        }
    }
}