// BEND — rotate, radially spread, and barrel-warp the frame together: a
// single lens-like twist rather than a straight rotozoom.
{
    name: "Bend"
    engine: "screen"
    input0: "test"

    p0: 0.5  p1: 0.5  p2: 0.5
    dials: [
        {name: "ROTATE", bind: "p0", default: 0.5},
        {name: "SPREAD", bind: "p1", default: 0.5},
        {name: "BARREL", 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 tau = 6.2831853
            let ang = (self.user.x - 0.5) * 1.4 + sin(self.sig.x * tau) * 0.04
            let cs = cos(ang)
            let sn = sin(ang)
            let c = uv - vec2(0.5, 0.5)
            let r0 = vec2(c.x * cs - c.y * sn, c.x * sn + c.y * cs)
            let spread = 0.5 + 1.4 * self.user.y
            let r1 = r0 * spread
            let rad = length(r1)
            let barrel = 1.0 + (0.2 + 1.6 * self.user.z) * 0.4 * rad * rad * (0.4 + self.time_beat.w * 0.6)
            let r2 = r1 * barrel
            let w = r2 + vec2(0.5, 0.5)
            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)
        }
    }
}