Reduce point cloud data to positional data

src/clients/reconstruction-client.js

@@ -22,6 +22,7 @@ import {
   distanceFloats2Canvas,
   depthFloats2Canvas,
 } from '../generators/sg-debug.js';
+import { destructurePointCloud } from '../utils/point-cloud.js';
 
 //
 
@@ -462,7 +463,11 @@ export async function getPointCloud(blob, {
   });
   if (res.ok) {
     const headers = Object.fromEntries(res.headers.entries());
-    const arrayBuffer = await res.arrayBuffer();
+
+    // This will probably be handled server-side eventually.
+    const _arrayBuffer = await res.arrayBuffer();
+    const arrayBuffer = destructurePointCloud(_arrayBuffer).points;
+
     return {
       headers,
       arrayBuffer,
@@ -516,4 +521,4 @@ export function pointCloudArrayBufferToColorAttributeArray(labelImageData, uint8
       // none
     }
   }
-}
+}

src/utils/point-cloud.js

@@ -0,0 +1,39 @@
+import { pointCloudFullStride } from '../zine/zine-constants.js'
+
+
+/**
+ * Destructure a point cloud into its component parts.
+ */
+export function destructurePointCloud(arrayBuffer) {
+  const numPoints = arrayBuffer.byteLength / pointCloudFullStride;
+  const points = new Float32Array(numPoints * 3);
+  const colors = new Uint8Array(numPoints * 3);
+  const intensities = new Uint8Array(numPoints);
+  const classifications = new Uint8Array(numPoints);
+  const dataView = new DataView(arrayBuffer);
+
+  let pointIndex = 0;
+  let colorIndex = 0;
+  let intensityIndex = 0;
+  let classificationIndex = 0;
+
+  for (let i = 0; i < arrayBuffer.byteLength; i += pointCloudFullStride) {
+    points[pointIndex++] = dataView.getFloat32(i, true);
+    points[pointIndex++] = dataView.getFloat32(i + 4, true);
+    points[pointIndex++] = dataView.getFloat32(i + 8, true);
+
+    colors[colorIndex++] = arrayBuffer[i + 12];
+    colors[colorIndex++] = arrayBuffer[i + 13];
+    colors[colorIndex++] = arrayBuffer[i + 14];
+
+    intensities[intensityIndex++] = arrayBuffer[i + 15];
+    classifications[classificationIndex++] = arrayBuffer[i + 16];
+  }
+
+  return {
+    points: points.buffer,
+    colors: colors.buffer,
+    intensities: intensities.buffer,
+    classifications: classifications.buffer,
+  };
+}