Asset managers are the second kind of management class in Simulant (the other being StageNode managers). All assets in Simulant use a refcounted manager, these assets include:
In normal usage, these materials are linked just after creation to another asset (e.g. Texture -> Material) or to an object that has a manual manager (e.g. an Actor). A asset can obviously be linked to more than one object but when all linked objects/assets are destroyed, then the refcounted manager will delete the asset.
There are (currently) two different kinds of GarbageCollectMethod that you can set on a object, these are:
GARBAGE_COLLECT_NEVER - Never delete the object, keep it around indefinitely until the GC method is changedGARBAGE_COLLECT_PERIODIC - The object will be deleted at some point after the final reference is released.When you create a asset, you need to maintain a reference to it otherwise the asset will be destroyed.
For example, say you load a mesh, like so:
MeshPtr my_mesh = stage->new_mesh_from_file("test.obj");
The mesh will stay loaded while my_mesh is in scope, but then it will be released unless you either store the
MeshPtr somewhere persistent, or attach the mesh to a stage node. e.g.
stage->new_actor_with_mesh(my_mesh); //Links the mesh to an actor, preventing its destruction
Sometimes you want to load a asset once, but there will be periods of time where it won't be attached to anything.
Imagine, for example, you have a Mesh for a torpedo. When the player fires a torpedo, you'd associate the Mesh to a new Actor, and when the torpedo detonates, the Actor will be destroyed. If that was the only torpedo in play, this would mean the mesh was no longer linked to any Actor, and so would be garbage collected meaning next time the player fires, you'll need to reload the Mesh! Not ideal!
Fortunately, when you create a mesh, you can disable its garbage collection on a case-by-case basis:
MeshPtr torpedo_mesh = stage()->new_mesh_from_file(
"torpedo.obj",
MeshLoadOptions(),
GARBAGE_COLLECT_NEVER
);
Now the torpedo_mesh will never be garbage collected. When you are absolutely finished with it, you can call:
topedo_mesh->set_garbage_collection_method(GARBAGE_COLLECT_PERIODIC);
The torpedo will then be cleaned up at the next run of the garbage collector.
Simulant needs at minimum a default material, and a default font file. These are normally set to Material::BuiltIns::DEFAULT and Orbitron respectively but you can set them per manager by calling AssetManager::set_default_material_filename() and AssetManager::set_default_font_filename()