// RIPPLE WIPE — an interference field of layered sine and cosine ripples
// sweeps deck B in instead of a straight edge: pixels caught in a trough
// reveal first, pixels riding a crest hold onto deck A longest. RATE
// sets the ripple frequency, FLIP inverts which pixels go first.
{
    name: "Ripple Wipe"
    engine: "transition"
    dials: [
        {name: "SOFT", bind: "p0", default: 0.12},
        {name: "RATE", bind: "p1", default: 0.4},
        {name: "FLIP", bind: "p2", default: 0.0}
    ]
    shader: draw.DrawVjFxDuo {
        trans: fn(uv: vec2, t: float) -> vec4 {
            let p = vec2((uv.x - 0.5) * self.aspect(), uv.y - 0.5)
            let r = length(p)
            let freq = 4.0 + self.user.y * 16.0
            let f1 = sin(r * freq * 6.283 - p.x * freq * 2.0)
            let f2 = cos((p.x + p.y) * freq * 3.0)
            let mut field = clamp(f1 * 0.3 + f2 * 0.3 + 0.5, 0.0, 1.0)
            field = mix(field, 1.0 - field, step(0.5, self.user.z))
            let soft = 0.01 + self.user.x * 0.3
            let tt = t * (1.0 + 2.0 * soft) - soft
            let m = smoothstep(tt - soft, tt + soft, field)
            return self.deck_b(uv).mix(self.deck_a(uv), m)
        }
    }
}