// SUCK — a straight radial pinch toward the centre, the sampled radius
// pulled in by a beat-eased power curve, with a TWIST added near the core.
{
    name: "Suck"
    engine: "screen"
    input0: "test"

    p0: 0.5  p1: 0.5  p2: 0.5
    dials: [
        {name: "PINCH", bind: "p0", default: 0.5},
        {name: "TWIST", bind: "p1", default: 0.5},
        {name: "REACH", bind: "p2", default: 0.5}
    ]

    stages: [
        {kind: "bloom", threshold: 0.6, strength: 1.05, levels: 2}
    ]

    shader: draw.DrawVjFxScreen {
        fx_color: fn(uv: vec2, content: vec4, cmix: float) -> vec4 {
            let center = vec2(0.5, 0.5)
            let d = uv - center
            let r = length(d)
            let reach = 0.3 + 0.5 * self.user.z
            let t = clamp(r / reach, 0.0, 1.0)
            let pinch = 0.3 + 1.3 * self.user.x
            let ease = 1.0 + pinch * (1.0 - 0.4 * self.time_beat.w)
            let newr = pow(t, ease) * reach
            let ang0 = atan2(d.y, d.x)
            let twist = (1.0 - t) * (2.0 + 6.0 * self.user.y)
            let ang = ang0 + twist
            let nd = vec2(cos(ang), sin(ang)) * newr
            let blend = 1.0 - smoothstep(reach * 0.85, reach, r)
            let w = center + mix(d, nd, blend)
            let tex = self.tex0.sample_as_bgra(clamp(w, vec2(0.0, 0.0), vec2(1.0, 1.0)))
            return vec4(tex.xyz, 1.0)
        }
    }
}