Use lazy-loading helper for PBR material imports

Author: MiiBond

packages/dev/loaders/src/glTF/2.0/glTFLoader.ts

@@ -92,6 +92,10 @@ import type { IMaterialLoadingAdapter } from "./materialLoadingAdapter";
 // Caching these dynamic imports gives a surprising perf boost (compared to importing them directly each time).
 const LazyAnimationGroupModulePromise = new Lazy(() => import("core/Animations/animationGroup"));
 const LazyLoaderAnimationModulePromise = new Lazy(() => import("./glTFLoaderAnimation"));
+const LazyOpenPBRMaterialLoadingAdapterModulePromise = new Lazy(() => import("./openPbrMaterialLoadingAdapter"));
+const LazyPBRMaterialLoadingAdapterModulePromise = new Lazy(() => import("./pbrMaterialLoadingAdapter"));
+const LazyOpenPBRMaterialModulePromise = new Lazy(() => import("core/Materials/PBR/openPbrMaterial"));
+const LazyPBRMaterialModulePromise = new Lazy(() => import("core/Materials/PBR/pbrMaterial"));
 
 export { GLTFFileLoader };
 
@@ -2226,16 +2230,16 @@ export class GLTFLoader implements IGLTFLoader {
      */
     private async _ensurePbrMaterialClassesAsync(): Promise<void> {
         if (!this._pbrMaterialClass || !this._pbrMaterialAdapterClass) {
-            const openpbrExt = this._extensions.find((extension) => extension.name === "KHR_materials_openpbr");
-            if (this.parent.useOpenPBR || openpbrExt) {
-                const materialAdapterModule = await import("./openPbrMaterialLoadingAdapter");
+            const isOpenPbr = this.isExtensionUsed("KHR_materials_openpbr");
+            if (this.parent.useOpenPBR || isOpenPbr) {
+                const materialAdapterModule = await LazyOpenPBRMaterialLoadingAdapterModulePromise.value;
                 this._pbrMaterialAdapterClass = materialAdapterModule.OpenPBRMaterialLoadingAdapter;
-                const materialModule = await import("core/Materials/PBR/openPbrMaterial");
+                const materialModule = await LazyOpenPBRMaterialModulePromise.value;
                 this._pbrMaterialClass = materialModule.OpenPBRMaterial;
             } else {
-                const materialAdapterModule = await import("./pbrMaterialLoadingAdapter");
+                const materialAdapterModule = await LazyPBRMaterialLoadingAdapterModulePromise.value;
                 this._pbrMaterialAdapterClass = materialAdapterModule.PBRMaterialLoadingAdapter;
-                const materialModule = await import("core/Materials/PBR/pbrMaterial");
+                const materialModule = await LazyPBRMaterialModulePromise.value;
                 this._pbrMaterialClass = materialModule.PBRMaterial;
             }
         }