binary stl reader

web/app/3d/stl/stl-binary-reader.js

@@ -0,0 +1,38 @@
+import {StlSolid, StlFace} from './stl-data-structure'
+
+function readVector(dataView, off) {
+  return [
+    dataView.getFloat32(off + 0, true),
+    dataView.getFloat32(off + 4, true),
+    dataView.getFloat32(off + 8, true)
+  ];
+}
+
+export function parse(dataView) {
+  const solid = new StlSolid('binary');
+  let off = 80; // skip header
+
+  let triangleCount = dataView.getUint32(off, true);
+  off += 4;
+
+  let cells = [];
+  let positions = [];
+  let faceNormals = [];
+
+  for (let i = 0; i < triangleCount; i++) {
+    let cell = [];
+    let normal = readVector(dataView, off);
+    off += 12; // 3 floats
+
+    let face = new StlFace(normal);
+
+    for (let j = 0; j < 3; j++) {
+      let position = readVector(dataView, off);
+      off += 12;
+      face.vertices.push(position);
+    }
+    solid.faces.push(face);
+    off += 2; // skip attribute byte count
+  }
+  return solid;
+}