feat(web): decode RuView LiDAR wire frames

integrations/iphone-lidar/web/codec.mjs

@@ -0,0 +1,76 @@
+export function decodeLiDARPacket(packet) {
+  if (!packet || packet.type !== 'ruview.lidar.depth.v1') {
+    throw new Error('Unsupported LiDAR packet type');
+  }
+
+  const { depth } = packet;
+  if (!depth || depth.encoding !== 'u16le-mm+u8-confidence') {
+    throw new Error('Unsupported depth encoding');
+  }
+
+  const mmBytes = base64ToBytes(depth.millimetersBase64);
+  const confidence = base64ToBytes(depth.confidenceBase64);
+  const expectedPixels = depth.width * depth.height;
+
+  if (mmBytes.byteLength !== expectedPixels * 2) {
+    throw new Error(`Depth payload length mismatch: expected ${expectedPixels * 2}, got ${mmBytes.byteLength}`);
+  }
+  if (confidence.byteLength !== expectedPixels) {
+    throw new Error(`Confidence payload length mismatch: expected ${expectedPixels}, got ${confidence.byteLength}`);
+  }
+
+  const view = new DataView(mmBytes.buffer, mmBytes.byteOffset, mmBytes.byteLength);
+  const meters = new Float32Array(expectedPixels);
+  for (let i = 0; i < expectedPixels; i += 1) {
+    meters[i] = view.getUint16(i * 2, true) / 1000;
+  }
+
+  return {
+    ...packet,
+    depth: {
+      width: depth.width,
+      height: depth.height,
+      meters,
+      confidence,
+    },
+  };
+}
+
+export function depthToPointCloud(frame, confidenceThreshold = 1) {
+  const { width, height, meters, confidence } = frame.depth;
+  const { fx, fy, cx, cy, imageWidth, imageHeight } = frame.intrinsics;
+
+  const sx = width / imageWidth;
+  const sy = height / imageHeight;
+  const scaledFx = fx * sx;
+  const scaledFy = fy * sy;
+  const scaledCx = cx * sx;
+  const scaledCy = cy * sy;
+
+  const points = [];
+  for (let v = 0; v < height; v += 1) {
+    for (let u = 0; u < width; u += 1) {
+      const index = v * width + u;
+      const z = meters[index];
+      if (!Number.isFinite(z) || z <= 0 || confidence[index] < confidenceThreshold) continue;
+
+      const x = ((u - scaledCx) / scaledFx) * z;
+      const y = ((v - scaledCy) / scaledFy) * z;
+      points.push([x, -y, -z]);
+    }
+  }
+  return points;
+}
+
+function base64ToBytes(value) {
+  if (typeof Buffer !== 'undefined') {
+    return Uint8Array.from(Buffer.from(value, 'base64'));
+  }
+
+  const binary = atob(value);
+  const bytes = new Uint8Array(binary.length);
+  for (let i = 0; i < binary.length; i += 1) {
+    bytes[i] = binary.charCodeAt(i);
+  }
+  return bytes;
+}