fix: harden merged map resource cleanup

src/components/three/models/generated/EcoleModel.tsx

@@ -89,7 +89,8 @@ function createMergedMeshes(scene: THREE.Group): MergedMeshData[] {
     });
   });
 
-  return [...groups.values()].map((group) => {
+  return [...groups.values()]
+    .map((group) => {
       if (group.geometries.length === 1) {
         return {
           geometry: group.geometries[0] as THREE.BufferGeometry,
@@ -103,11 +104,17 @@ function createMergedMeshes(scene: THREE.Group): MergedMeshData[] {
         sourceGeometry.dispose();
       }
 
+      if (!geometry) {
+        disposeMaterial(group.material);
+        return null;
+      }
+
       return {
         geometry,
         material: group.material,
       };
-  });
+    })
+    .filter((meshData): meshData is MergedMeshData => meshData !== null);
 }
 
 export function EcoleModel({

src/world/map-instancing/InstancedMapAsset.tsx

@@ -93,7 +93,8 @@ function extractMeshes(scene: THREE.Group): MeshData[] {
     });
   });
 
-  return [...groups.values()].map((group) => {
+  return [...groups.values()]
+    .map((group) => {
       if (group.geometries.length === 1) {
         return {
           geometry: group.geometries[0] as THREE.BufferGeometry,
@@ -107,11 +108,17 @@ function extractMeshes(scene: THREE.Group): MeshData[] {
         geometry.dispose();
       }
 
+      if (!mergedGeometry) {
+        disposeMaterialOnly(group.material);
+        return null;
+      }
+
       return {
         geometry: mergedGeometry,
         material: group.material,
       };
-  });
+    })
+    .filter((meshData): meshData is MeshData => meshData !== null);
 }
 
 function setInstanceMatrices(

src/world/vegetation/InstancedVegetation.tsx

@@ -3,7 +3,6 @@ import * as THREE from "three";
 import { useGLTF } from "@react-three/drei";
 import { mergeGeometries } from "three/addons/utils/BufferGeometryUtils.js";
 import type { VegetationInstance } from "@/world/vegetation/useVegetationData";
-import { disposeInstancedMesh } from "@/utils/three/dispose";
 
 interface InstancedVegetationProps {
   modelPath: string;
@@ -143,7 +142,7 @@ export function InstancedVegetation({
     return () => {
       for (const mesh of instancedMeshes) {
         group.remove(mesh);
-        disposeInstancedMesh(mesh);
+        mesh.dispose();
       }
     };
   }, [instancedMeshes]);