// RING BLOOM — deck B blooms outward from centre inside a set of
// concentric ripples, so the growing edge looks like rings rather than
// a plain circle. RINGS sets the ripple count.
{
    name: "Ring Bloom"
    engine: "transition"
    p1: 0.5
    dials: [
        {name: "SOFT", bind: "p0", default: 0.08},
        {name: "RINGS", bind: "p1", default: 0.5},
        {name: "DIP", bind: "p2", default: 0.0}
    ]
    shader: draw.DrawVjFxDuo {
        trans: fn(uv: vec2, t: float) -> vec4 {
            let c2 = vec2((uv.x - 0.5) * self.aspect(), uv.y - 0.5)
            let r = length(c2)
            let rmax = 0.5 * sqrt(self.aspect() * self.aspect() + 1.0)
            let rings = 3.0 + floor(self.user.y * 5.0)
            let ripple = sin(r * rings * 6.2832) * 0.03
            let field = r + ripple
            let soft = 0.01 + self.user.x * 0.15
            let edge = t * (rmax + 2.0 * soft) - soft
            let inside = smoothstep(edge + soft, edge - soft, field)
            let c = self.deck_a(uv).mix(self.deck_b(uv), inside)
            let dim = 1.0 - 4.0 * clamp(t, 0.0, 1.0) * (1.0 - clamp(t, 0.0, 1.0)) * self.user.z * 0.9
            return vec4(c.xyz * dim, 1.0)
        }
    }
}