feat: udp stream

test/pixelstream/bouncing-ball.js

@@ -0,0 +1,80 @@
+const dgram = require('dgram');
+
+const host = process.argv[2];
+const port = parseInt(process.argv[3] || '4210', 10);
+const pixels = parseInt(process.argv[4] || '64', 10);
+const intervalMs = parseInt(process.argv[5] || '30', 10);
+
+if (!host) {
+  console.error('Usage: node bouncing-ball.js <device-ip> [port] [pixels] [interval-ms]');
+  process.exit(1);
+}
+
+const socket = dgram.createSocket('udp4');
+const isBroadcast = host === '255.255.255.255' || host.endsWith('.255');
+
+let position = Math.random() * (pixels - 1);
+let velocity = randomVelocity();
+
+function randomVelocity() {
+  const min = 0.15;
+  const max = 0.4;
+  const sign = Math.random() < 0.5 ? -1 : 1;
+  return (min + Math.random() * (max - min)) * sign;
+}
+
+function rebound(sign) {
+  velocity = randomVelocity() * sign;
+}
+
+function mix(a, b, t) {
+  return a + (b - a) * t;
+}
+
+function generateFrame() {
+  const dt = intervalMs / 1000;
+  position += velocity * dt * 60; // scale velocity to 60 FPS reference
+
+  if (position < 0) {
+    position = -position;
+    rebound(1);
+  } else if (position > pixels - 1) {
+    position = (pixels - 1) - (position - (pixels - 1));
+    rebound(-1);
+  }
+
+  const activeIndex = Math.max(0, Math.min(pixels - 1, Math.round(position)));
+
+  let payload = 'RAW:';
+  for (let i = 0; i < pixels; i++) {
+    if (i === activeIndex) {
+      payload += 'ff8000';
+      continue;
+    }
+
+    const distance = Math.abs(i - position);
+    const intensity = Math.max(0, 1 - distance);
+    const green = Math.round(mix(20, 200, intensity)).toString(16).padStart(2, '0');
+    const blue = Math.round(mix(40, 255, intensity)).toString(16).padStart(2, '0');
+    payload += '00' + green + blue;
+  }
+
+  return payload;
+}
+
+function sendFrame() {
+  const payload = generateFrame();
+  const message = Buffer.from(payload, 'utf8');
+  socket.send(message, port, host);
+}
+
+setInterval(sendFrame, intervalMs);
+
+if (isBroadcast) {
+  socket.bind(() => {
+    socket.setBroadcast(true);
+  });
+}
+
+console.log(`Streaming bouncing ball pattern to ${host}:${port} with ${pixels} pixels (interval=${intervalMs}ms)`);
+