124 lines
2.8 KiB
TypeScript
124 lines
2.8 KiB
TypeScript
import { canvas2d } from "./lib/html";
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import { Prng, mulberry32 } from "./lib/prng";
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const BLOWUP = 4;
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const WIDTH = 240;
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const HEIGHT = 135;
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type Lookup2d = (x: number, y: number) => number;
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function dim(width: number, height: number): Lookup2d {
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return function xy(x: number, y: number) {
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return (
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(((x % width) + width) % width) +
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width * (((y % height) + height) % height)
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);
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};
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}
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class IslandGrid {
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data: number[];
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rng: Prng;
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xy: Lookup2d;
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constructor(public width: number, public height: number, seed: number) {
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this.data = Array(width * height).fill(0);
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this.rng = mulberry32(seed);
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this.xy = dim(width, height);
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}
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public get(x: number, y: number): number {
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return this.data[this.xy(x, y)];
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}
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public set(x: number, y: number, tile: number) {
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this.data[this.xy(x, y)] = tile;
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console.log(x, y, this.xy(x, y), this.data[this.xy(x, y)]);
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}
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public floodSearch(
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startPos: number,
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shouldExpand: (tile: number) => boolean
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): number[] {
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const len = this.data.length;
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const width = this.width;
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const seen = new Uint8Array(len);
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const hitPositions: number[] = [];
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function enqueue(pos: number) {
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if (!seen[pos]) {
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hitPositions.push(pos);
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seen[pos] = 1;
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}
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}
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enqueue(startPos);
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for (let i = 0; i < hitPositions.length; i++) {
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const pos = hitPositions[i];
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if (shouldExpand(this.data[pos])) {
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enqueue((pos - width) % len);
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enqueue((pos - 1) % len);
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enqueue((pos + 1) % len);
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enqueue((pos + width) % len);
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}
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}
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return hitPositions;
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}
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}
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function renderIslands(islands: IslandGrid, cx: CanvasRenderingContext2D) {
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for (let y = 0; y < islands.height; y++) {
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for (let x = 0; x < islands.width; x++) {
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const tile = islands.data[islands.xy(x, y)];
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switch (tile) {
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case 0:
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cx.fillStyle = "blue";
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break;
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case 1:
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cx.fillStyle = "yellow";
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break;
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case 2:
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cx.fillStyle = "#00ff00";
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break;
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case 3:
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cx.fillStyle = "#008800";
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break;
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default:
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cx.fillStyle = "#666666";
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break;
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}
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cx.fillRect(x, y, 1, 1);
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}
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}
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}
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export function IslandApplet() {
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const [canvas, cx] = canvas2d({
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width: WIDTH * BLOWUP,
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height: HEIGHT * BLOWUP,
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});
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cx.scale(BLOWUP, BLOWUP);
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const islands = new IslandGrid(WIDTH, HEIGHT, 128);
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function tick() {
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const pos = islands.rng() % islands.data.length;
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islands
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.floodSearch(pos, (tile) => tile > 0)
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.forEach((pos) => islands.data[pos]++);
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renderIslands(islands, cx);
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}
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tick();
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setInterval(tick, 1000 / 10);
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return [canvas];
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}
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(globalThis as any).IslandApplet = IslandApplet;
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