2026-lightning-talk/fall.html at main · sitcon-tw/2026-lightning-talk · GitHub

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<!doctype html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>Falling Balls Example</title>
		<script src="https://cdn.jsdelivr.net/npm/matter-js@0.19.0/build/matter.min.js"></script>
		<style>
			html,
			body {
				margin: 0;
				padding: 0;
				background: #111;
				overflow: hidden;
			}
		</style>
	</head>

	<body>
		<script>
			const { Engine, Render, Runner, World, Bodies } = Matter;

			// world + physics
			const engine = Engine.create();
			const world = engine.world;

			const width = window.innerWidth;
			const height = window.innerHeight;

			// renderer
			const render = Render.create({
				element: document.body,
				engine,
				options: {
					width,
					height,
					background: "#00FF00",
					wireframes: false
				}
			});

			Render.run(render);
			const runner = Runner.create();
			Runner.run(runner, engine);

			// static walls
			const ground = Bodies.rectangle(width / 2, height + 50, width, 100, { isStatic: true });
			const left = Bodies.rectangle(-50, height / 2, 100, height, { isStatic: true });
			const right = Bodies.rectangle(width + 50, height / 2, 100, height, { isStatic: true });

			World.add(world, [ground, left, right]);

			// generate balls
			function spawnBall() {
				const x = Math.random() * width;
				const r = 10 + Math.random() * 30;
				const color = `hsl(${Math.random() * 360}, 80%, 60%)`;

				const ball = Bodies.circle(x, -50, r, {
					restitution: 0.6, // 推薦 0.3~0.6
					friction: 0,
					render: {
						fillStyle: color
					}
				});

				World.add(world, ball);
			}

			// drop a ball every 70ms
			setInterval(spawnBall, 70);

			// handle window resize
			window.addEventListener("resize", () => {
				location.reload(); // 簡單粗暴，保持一致
			});
		</script>
	</body>
</html>