feat: implement fragment cloning

packages/fragments/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@thatopen/fragments",
   "description": "Simple geometric system built on top of Three.js to display 3D BIM data efficiently.",
-  "version": "2.1.5",
+  "version": "2.1.6",
   "author": "That Open Company",
   "contributors": [
     "Antonio Gonzalez Viegas (https://github.com/agviegas)",

packages/fragments/src/fragment-mesh.ts

@@ -118,4 +118,10 @@ export class FragmentMesh extends THREE.InstancedMesh {
       colors,
     };
   }
+
+  clone(_recursive?: boolean): any {
+    throw new Error(
+      "Fragment meshes can't be cloned directly. Use mesh.fragment.clone instead!",
+    );
+  }
 }

packages/fragments/src/fragment.ts

@@ -546,6 +546,51 @@ export class Fragment {
     return { ...geometry, ids, id };
   }
 
+  /**
+   * Creates a copy of the whole fragment or a part of it. It shares the geometry with the original fragment, but has its own InstancedMesh data, so it also needs to be disposed.
+   *
+   * @param itemIDs - An iterable of item IDs to be included in the clone.
+   *
+   */
+  clone(itemIDs: Iterable<number> = this.ids) {
+    const newFragment = new Fragment(
+      this.mesh.geometry,
+      this.mesh.material,
+      this.capacity,
+    );
+
+    const items: Item[] = [];
+
+    for (const id of itemIDs) {
+      const instancesIDs = this.getInstancesIDs(id);
+      if (instancesIDs === null) {
+        continue;
+      }
+
+      const transforms: THREE.Matrix4[] = [];
+      const colors: THREE.Color[] = [];
+
+      for (const instanceID of instancesIDs) {
+        const newMatrix = new THREE.Matrix4();
+        const newColor = new THREE.Color();
+        this.mesh.getMatrixAt(instanceID, newMatrix);
+        this.mesh.getColorAt(instanceID, newColor);
+        transforms.push(newMatrix);
+        colors.push(newColor);
+      }
+
+      items.push({
+        id,
+        transforms,
+        colors,
+      });
+    }
+
+    newFragment.add(items);
+
+    return newFragment;
+  }
+
   private putLast(instanceID1: number) {
     if (this.mesh.count === 0) return;
 

packages/fragments/src/fragments-group.ts

@@ -404,6 +404,86 @@ export class FragmentsGroup extends THREE.Group {
     return result;
   }
 
+  clone(_recursive?: boolean): any {
+    throw new Error("Use FragmentsGroup.cloneGroup instead!");
+  }
+
+  /**
+   * Creates a copy of the whole group or a part of it. Each fragment clone shares the geometry of with its respective original fragment, but has its own InstancedMesh data, so it also needs to be disposed.
+   *
+   * @param items - Optional - The part of the group to be cloned. If not given, the whole group is cloned.
+   *
+   */
+  cloneGroup(items?: FragmentIdMap) {
+    const newGroup = new FragmentsGroup();
+
+    newGroup.coordinationMatrix = this.coordinationMatrix;
+    newGroup.position.copy(this.position);
+    newGroup.rotation.copy(this.rotation);
+    newGroup.scale.copy(this.scale);
+    newGroup.updateMatrix();
+
+    newGroup.ifcMetadata = { ...this.ifcMetadata };
+
+    if (!items) {
+      items = this.getFragmentMap(this.data.keys());
+    }
+
+    const allIDs = new Set<number>();
+
+    const fragmentIDConversion = new Map<string, string>();
+
+    for (const fragment of this.items) {
+      if (!items[fragment.id]) {
+        continue;
+      }
+
+      const ids = items[fragment.id];
+      const newFragment = fragment.clone(ids);
+
+      fragmentIDConversion.set(fragment.id, newFragment.id);
+
+      newGroup.items.push(newFragment);
+      newGroup.add(newFragment.mesh);
+
+      for (const expressID of ids) {
+        allIDs.add(expressID);
+      }
+    }
+
+    for (const id of allIDs) {
+      const data = this.data.get(id);
+      if (data) {
+        newGroup.data.set(id, data);
+      }
+    }
+
+    for (const [fragKey, fragID] of this.keyFragments) {
+      if (fragmentIDConversion.has(fragID)) {
+        const newID = fragmentIDConversion.get(fragID);
+        if (newID === undefined) {
+          throw new Error("Malformed fragment ID map during clone!");
+        }
+        newGroup.keyFragments.set(fragKey, newID);
+      }
+    }
+
+    for (const [globalID, expressID] of this.globalToExpressIDs) {
+      if (allIDs.has(expressID)) {
+        newGroup.globalToExpressIDs.set(globalID, expressID);
+      }
+    }
+
+    if (this.civilData) {
+      newGroup.civilData = {
+        coordinationMatrix: this.coordinationMatrix,
+        alignments: new Map(),
+      };
+    }
+
+    return newGroup as this;
+  }
+
   private getPropsURL(id: number) {
     const { ids } = this.streamSettings;
     const fileID = ids.get(id);