The idea is that later there will be more loaders which would load different formats (like OBJLoader, ColladaLoader).
Usage (async JS):
var loader = new THREE.Loader();
loader.loadAsync( "obj/torus/Torus.js", function() { createScene( new Torus() ) } );
Usage (web worker):
var loader = new THREE.Loader();
loader.loadWorker( "obj/torus/Torus_slim.js", function( geometry ) { createScene( geometry ) } );
Web worker loader is useful for large meshes, where it allows browser to stay responsive for longer time and also it can handle larger meshes than async JS loader.
Web worker loader needs a simpler format of the model. Web workers can communicate with the main application only via message passing, where messages are JSON objects.
There is a new version of OBJ -> Three.js converter (convert_obj_threejs_slim.py) which can produce model in format needed for web workers.
All examples which were using models from OBJ converter were refactored to use Loader.
Except large mesh example, all examples are using just async JS loading. Web worker loading is there, it's just commented out, as it's a bit pain for local development.
Chrome doesn't allow to run web workers from pages accessed via file://, so you need either to run it with "--allow-file-access-from-files" flag, or access examples via local server (http://localhost/example.html).
alteredq