hud observation for generic game objects

src/lib/MeshUtils.js

@@ -1,4 +1,4 @@
-import { TextureLoader } from "three";
+import { TextureLoader, Box3, Vector3 } from "three";
 
 function assignParams(mesh, params){
     ['scale', 'rotation', 'position'].forEach(p=>params[p] && mesh[p].fromArray(params[p]));
@@ -26,4 +26,27 @@ function assignMaterial(mesh, params){
     }
 }
 
-export { assignParams, assignMaterial }
+function getBoundingBox(object){
+    return new Box3().setFromObject(object);
+}
+
+function getBoundingBoxMaxLength(bb){
+    return Math.max(bb.max.x - bb.min.x, bb.max.y - bb.min.y, bb.max.z - bb.min.z)
+}
+
+function getBoundingBoxCenterPoint(bb, relativeTo){
+    relativeTo = relativeTo || new Vector3(0,0,0)
+    return new Vector3(
+        bb.min.x + (bb.max.x - bb.min.x)/2 - relativeTo.x, 
+        bb.min.y + (bb.max.y - bb.min.y)/2 - relativeTo.y, 
+        bb.min.z + (bb.max.z - bb.min.z)/2 - relativeTo.z
+    )
+}
+
+function autoScale(object, mk = 1) {
+    let bb = getBoundingBox(object);
+    let k = getBoundingBoxMaxLength(bb);
+    object.scale.multiplyScalar(mk / k);
+}
+
+export { assignParams, assignMaterial, autoScale, getBoundingBox, getBoundingBoxMaxLength, getBoundingBoxCenterPoint }