Core Strata

1"use client";
2 
3import * as React from "react";
4 
5import { cn } from "@/lib/utils";
6import { useReducedMotion, useVisibilityPause } from "@/lib/motiq";
7 
8/* -------------------------------------------------------------------------- */
9/* Types                                                                      */
10/* -------------------------------------------------------------------------- */
11 
12export interface CoreStrataRect {
13  /** 0–1 left edge of the readable safe area. */
14  x: number;
15  /** 0–1 top edge of the readable safe area. */
16  y: number;
17  /** 0–1 width of the readable safe area. */
18  w: number;
19  /** 0–1 height of the readable safe area. */
20  h: number;
21}
22 
23export interface CoreStrataProps extends React.HTMLAttributes<HTMLDivElement> {
24  /** Sediment band density — more, thinner bands and more frequent marker seams at higher values. ~0.4–1.8. */
25  density?: number;
26  /** Overall luminance/opacity of the strata field (0–1.4). */
27  intensity?: number;
28  /** Vertical core-scroll + survey-beam speed multiplier. 0 parks the beam at `readingLine` (still legible). */
29  speed?: number;
30  /** Number of baked diagonal fault breaks that vertically offset the strata columns (clamped 1–6). */
31  faults?: number;
32  /** 0–1 vertical position of the fixed reading-line datum; also where the survey beam parks when motion stops. */
33  readingLine?: number;
34  /** Region where a radial quiet-zone scrim dims the strata so foreground text stays readable. */
35  safeArea?: CoreStrataRect;
36  /** Marker/ignition + reading-line color. Defaults to the fixed Motion Lab amber (#e8a852) when unset. */
37  accent?: string;
38  /** Deterministic seed for the generated geometry (SSR-stable). */
39  seed?: number;
40  /** Pause the scroll + beam sweep when scrolled offscreen or the tab is hidden. */
41  pauseWhenHidden?: boolean;
42  /** Force the static, motion-free variant regardless of system preference. */
43  reducedMotion?: boolean;
44}
45 
46/* -------------------------------------------------------------------------- */
47/* Deterministic model                                                       */
48/* -------------------------------------------------------------------------- */
49 
50/** mulberry32 — no Math.random / Date.now at render or module scope (SSR-stable). */
51function makeRng(seed: number) {
52  let a = seed >>> 0;
53  return () => {
54    a = (a + 0x6d2b79f5) | 0;
55    let t = Math.imul(a ^ (a >>> 15), 1 | a);
56    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
57// … truncated