Refactor junction material handling to use MaterialDef

src/runtime-three/runtime-host.ts

@@ -4336,14 +4336,8 @@ export class RuntimeHost {
   }
 
   private createRuntimeJunctionMaterial(
-    runtimeScene: RuntimeSceneDefinition,
-    materialId: string | null
+    material: MaterialDef | null
   ): Material {
-    const material =
-      materialId === null
-        ? null
-        : (runtimeScene.materials?.[materialId] ?? null);
-
     return this.createRuntimeRoadGeneratedMaterial(material, 0x6f624d);
   }
 
@@ -4427,7 +4421,7 @@ export class RuntimeHost {
 
       const mesh = new Mesh(
         geometry,
-        this.createRuntimeJunctionMaterial(runtimeScene, junction.materialId)
+        this.createRuntimeJunctionMaterial(junction.material)
       );
       mesh.castShadow = false;
       mesh.receiveShadow = true;

src/runtime-three/runtime-scene-build.ts

@@ -2057,7 +2057,14 @@ export function buildRuntimeSceneFromDocument(
     .map((path) => buildRuntimePath(path, enabledTerrains, document));
   const splineCorridorJunctions = getSplineCorridorJunctions(
     document.splineCorridorJunctions
-  ).filter((junction) => junction.enabled);
+  )
+    .filter((junction) => junction.enabled)
+    .map((junction): RuntimeSplineCorridorJunction => ({
+      ...junction,
+      connections: junction.connections.map((connection) => ({ ...connection })),
+      center: cloneVec3(junction.center),
+      material: resolveRuntimeMaterial(document, junction.materialId)
+    }));
   const splineCorridorClipIntervalsByPath =
     resolveSplineCorridorJunctionClipIntervals({
       paths: getScenePaths(document.paths),