Custom Loader

Users can also create custom loaders to load custom resources:

@resourceLoader(FBX, ["fbx"])
export class FBXLoader extends Loader<FBXResource> {
	load(item: LoadItem, resourceManager: ResourceManager): AssetPromise<FBXResource> {
  	return new AssetPromise((resolve, reject)=> {
    	...
    })
  }
}

1. Use the @resourceLoader decorator to mark it as a ResourceLoader, passing in the type enum and the resource suffix to be parsed. In the example above, FBX is the type enum, and ["fbx"] is the suffix of the resource to be parsed.
2. Override the load method. The load method will receive loadItem and resourceManager. loadItem contains the basic information of the load, and resourceManager can help load other referenced resources.
3. Return an AssetPromise object. resolve the parsed resource result, for example, FBX returns a specific FBXResource.
4. If there is an error, reject the error.