new cursor laser beam

src/components/laser.js

@@ -0,0 +1,59 @@
+/**
+ * Laser beam.
+ * Automatically set length on intersection.
+ */
+AFRAME.registerComponent('cursor-laser', {
+  dependencies: ['sub-object'],
+
+  schema: {
+    hand: {type: 'string'}
+  },
+
+  init: function () {
+    const el = this.el;
+    const box = new THREE.Box3();
+    const size = new THREE.Vector3();
+
+    this.currentLength = undefined;
+    this.originalSize = undefined;
+
+    // Calculate size to position beam at tip of controller.
+    el.addEventListener('subobjectloaded', () => {
+      box.setFromObject(el.getObject3D('mesh'));
+      box.getSize(size);
+      el.object3D.position.z -= size.z;
+      this.originalSize = size.z;
+      this.currentLength = size.z;
+    });
+  },
+
+  tick: function () {
+    const el = this.el;
+
+    // Not yet ready.
+    if (this.currentLength === undefined) { return; }
+
+    const cursor = el.parentNode.components.cursor;
+    if (!cursor) { return; }
+
+    // Toggle beam.
+    const intersectedEl = cursor.intersectedEl;
+
+    if (!intersectedEl) {
+      // Retract the beam if not intersecting.
+      el.object3D.position.z = this.originalSize * -0.35;
+      el.object3D.scale.x = 0.25;
+      el.object3D.scale.z = this.originalSize * 0.35;
+      this.currentLength = this.originalSize * 0.35;
+      return;
+    }
+
+    // Set appropriate length of beam on intersection.
+    const intersection = el.parentNode.components.raycaster.intersections[0];
+    const ratio = intersection.distance / this.currentLength;
+    el.object3D.scale.x = 1;
+    el.object3D.position.z *= ratio;
+    el.object3D.scale.z *= ratio;
+    this.currentLength = el.object3D.scale.z;
+  }
+});

src/components/sub-object.js

@@ -0,0 +1,22 @@
+/**
+ * Pull a submesh out of a model file.
+ */
+AFRAME.registerComponent('sub-object', {
+  schema: {
+    from: {type: 'selector'},
+    name: {type: 'string'}
+  },
+
+  init: function () {
+    var el = this.el;
+    var data = this.data;
+
+    data.from.addEventListener('model-loaded', evt => {
+      const model = evt.detail.model;
+      const subset = model.getObjectByName(data.name);
+      el.setObject3D('mesh', subset.clone());
+      el.setAttribute('material', 'shader', 'flat');
+      el.emit('subobjectloaded', null, false);
+    });
+  }
+});