add physics to interactive objects

src/lib/MeshUtils.js

@@ -1,4 +1,4 @@
-import { TextureLoader, Box3, Vector3 } from "three";
+import { TextureLoader, Box3, Vector3, Group } from "three";
 
 function assignParams(mesh, params){
     ['scale', 'rotation', 'position'].forEach(p=>params[p] && mesh[p].fromArray(params[p]));
@@ -30,16 +30,22 @@ function getBoundingBox(object){
     return new Box3().setFromObject(object);
 }
 
+function getBoundingBoxSize(bb){
+    return new Vector3(bb.max.x - bb.min.x, bb.max.y - bb.min.y, bb.max.z - bb.min.z);
+}
+
 function getBoundingBoxMaxLength(bb){
-    return Math.max(bb.max.x - bb.min.x, bb.max.y - bb.min.y, bb.max.z - bb.min.z)
+    let size = getBoundingBoxSize(bb)
+    return Math.max(size.x, size.y, size.z)
 }
 
 function getBoundingBoxCenterPoint(bb, relativeTo){
     relativeTo = relativeTo || new Vector3(0,0,0)
+    let size = getBoundingBoxSize(bb)
     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
+        bb.min.x + (size.x)/2 - relativeTo.x, 
+        bb.min.y + (size.y)/2 - relativeTo.y, 
+        bb.min.z + (size.z)/2 - relativeTo.z
     )
 }
 
@@ -49,4 +55,16 @@ function autoScale(object, mk = 1) {
     object.scale.multiplyScalar(mk / k);
 }
 
-export { assignParams, assignMaterial, autoScale, getBoundingBox, getBoundingBoxMaxLength, getBoundingBoxCenterPoint }
+function centerOrigin(object){
+    let result = new Group();
+    let bb = getBoundingBox(object);
+    let position = getBoundingBoxCenterPoint(bb, object.position).negate();
+    object.position.copy(position)
+    result.add(object);
+    return result;
+}
+
+export { 
+    assignParams, assignMaterial, autoScale, centerOrigin,
+    getBoundingBox, getBoundingBoxSize, getBoundingBoxMaxLength, getBoundingBoxCenterPoint 
+}