// CARD GRID — the picture is a rack of cards, and once a bar a wave of
// flips runs across it: each card turns a half-turn on its vertical edge,
// lifting off the wall as it goes and dropping back flush.
//
// Pattern taught here: A STAGGERED MOVE THAT ALWAYS FINISHES. The stagger
// is a per-card delay taken out of the BAR PHASE, and the flip window is
// what is left over, so the last card to start still lands before the bar
// ends — the rack is guaranteed flat again on every downbeat, at any tempo.
// A stagger scaled off wall time instead would slide out of the bar the
// moment the BPM moved.
{
    name: "Card Grid"
    engine: "tiles"
    mode: "hook"
    seed: 53

    grid: 10
    spread: 8.8
    aspect: 0.62
    gap: 0.10

    input0: "test"

    speed: 1.0
    beat_pulse: 0.7
    beat_rate: 1.0
    bar_beats: 4

    // PERFORMANCE DIALS — mid-knob = the stock look, exact.
    p0: 0.5  p1: 0.5
    p2: "0.05 + 0.16 * pulse"
    dials: [
        {name: "WAVE", bind: "p0", default: 0.5},
        {name: "LIFT", bind: "p1", default: 0.5},
        {name: "EDGE", bind: "p2", default: 0.5}
    ]

    color_bg: #x0c0806
    color_a: #xffc25a
    color_b: #x8a3a12
    color_c: #xfff0d2

    fog: 0.0
    glow: 1.05

    stages: [
        {kind: "bloom", threshold: 0.68, strength: 1.0, 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 = the mode highlight drive, attr = (shade, edge, stagger, tumble).
    // Vertex hooks: fx_tile(id, grid, uv_window, t) -> (dx, dy, dz, scale),
    // fx_tile_spin(id, grid, uv_window, t) -> (axis.xyz, angle).
    // Signals: self.time_beat (time, beat, phase, pulse),
    // self.sig (bar, bpm, energy, dt), self.user (p0..p3),
    // self.shape.y = tiles per side, self.col_a/b/c/bg,
    // self.fog (density, glow, content, -).
    shader: draw.DrawVjFxTiles {
        // The card lifts toward the camera while it is edge-on and drops
        // back flush at both ends of its flip.
        fx_tile: fn(id: float, grid: vec2, uv_window: vec4, t: float) -> vec4 {
            let gw = max(self.shape.y, 1.0)
            // Delay ramps left-to-right and down the rack, plus a hash so
            // the wave frays instead of marching in ranks.
            let sweep = clamp(self.user.x, 0.0, 1.0)
            let lead = (grid.x / gw) * 0.38 + (1.0 - grid.y / gw) * 0.14
                + self.hash1(id * 3.31 + 2.0) * 0.30
            let stag = clamp(lead * (0.25 + 1.1 * sweep), 0.0, 0.74)
            let span = max(1.0 - stag, 0.20)
            let f = clamp((clamp(self.sig.x, 0.0, 1.0) - stag) / span, 0.0, 1.0)
            let turn = smoothstep(0.0, 1.0, f)
            // sin(pi*turn): zero flush, one edge-on, zero flush again.
            let lift = sin(turn * 3.1415927)
            let amt = (0.2 + 1.6 * clamp(self.user.y, 0.0, 1.0))
                * self.shape.z * 0.09
            return vec4(0.0, 0.0, lift * amt, 1.0)
        }

        // Half a turn per bar about the card's own vertical edge.
        fx_tile_spin: fn(id: float, grid: vec2, uv_window: vec4, t: float) -> vec4 {
            let gw = max(self.shape.y, 1.0)
            let sweep = clamp(self.user.x, 0.0, 1.0)
            let lead = (grid.x / gw) * 0.38 + (1.0 - grid.y / gw) * 0.14
                + self.hash1(id * 3.31 + 2.0) * 0.30
            let stag = clamp(lead * (0.25 + 1.1 * sweep), 0.0, 0.74)
            let span = max(1.0 - stag, 0.20)
            let f = clamp((clamp(self.sig.x, 0.0, 1.0) - stag) / span, 0.0, 1.0)
            let turn = smoothstep(0.0, 1.0, f)
            return vec4(0.0, 1.0, 0.0, turn * 3.1415927)
        }

        fx_color: fn(t: float, attr: vec4, content: vec4, cmix: float) -> vec4 {
            let border = attr.y
            let lit = content.xyz * (attr.x * (0.40 + 0.60 * border))
            // Warm card edge, hot while the wave is passing.
            let edge = 1.0 - border
            let glowline = self.col_c.xyz.mix(self.col_a.xyz, self.time_beat.w)
                * edge * (t + clamp(self.user.z, 0.0, 4.0) + 0.10)
            return vec4((lit + glowline) * self.fog.y, 1.0)
        }
    }
}