// Minimal family: one soft body drifting through a mostly empty frame.
//
// The quietest scene in the library, and the one an ambient intro or a long
// breakdown should usually land on. Nothing here reacts sharply — the beat
// mapping is deliberately weak, because a scene whose job is stillness should
// not twitch.

export const slowOrb = {
    name: 'Slow Orb',
    family: 'minimal',
    kind: 'fragment',

    params: {
        size:     { type: 'float', range: [0.15, 0.8], default: 0.38, uniform: 'u_size', bias: 'energy' },
        softness: { type: 'float', range: [0.2, 1.0],  default: 0.7,  uniform: 'u_softness' },
        drift:    { type: 'float', range: [0.01, 0.2], default: 0.05, uniform: 'u_drift', bias: 'motion', rate: true },
        wobble:   { type: 'float', range: [0, 0.5],    default: 0.15, uniform: 'u_wobble' },
        halo:     { type: 'float', range: [0, 1.2],    default: 0.4,  uniform: 'u_halo' },
        grain:    { type: 'float', range: [0, 0.5],    default: 0.12, uniform: 'u_grain' },
        palette:  { type: 'palette', count: 4 },
    },

    reactive: {
        size: { feature: 'loudness', amount: 0.12, response: 'smooth' },
        halo: { feature: 'beat',     amount: 0.15, response: 'spike' },
    },

    shader: `
vec4 scene(vec2 uv, vec2 p) {
    float t = u_time * u_drift + u_seed;

    vec2 centre = vec2(sin(t * 1.7) * 0.28, cos(t * 1.3) * 0.18);
    vec2 q = p - centre;

    // Break the silhouette so it never reads as a hard circle.
    float wobble = fbm(q * 2.4 + t, 4) * u_wobble;
    float d = length(q) * (1.0 + wobble) - u_size;

    float body = smoothstep(u_softness * 0.5, -u_softness * 0.5, d);
    float glow = exp(-max(d, 0.0) * (5.0 / max(u_halo, 0.05))) * u_halo;

    vec3 col = pal(0) * 0.05;
    col = mix(col, pal(1), body * 0.85);
    col += pal(2) * body * body * 0.5;
    col += pal(3) * glow * 0.35;

    // Fine grain keeps large flat areas from banding.
    col += (hash12(uv * 640.0 + floor(u_frame)) - 0.5) * u_grain * 0.08;

    return vec4(col, 1.0);
}
`,
};

export default slowOrb;