Prefabs/typed multi-entity templates

[junkdog]

@PrefabData("prefab/player.json")
public class PlayerPrefab extends Prefab {
    private ComponentMapper<Position> positionMapper;

    public PlayerPrefab(World world) {
        super(world, new FallbackFileResolver());
    }

    public SaveFileFormat createPlayer(float x, float y) {
        SaveFileFormat l = create();
        Entity player = l.get("player");

        positionMapper.get(player).xy.set(x, y);

        return l;
    }
}

• One Prefab creates 1 type of prefab specialization (uses same source json)
  • custom PrefabReader<JsonValue> implementations can be used for more dynamic/polymorphic prefabs
• @PrefabData(path) is passed to the FileHandleResolver
  • default implementations cache the JsonValue, to avoid re-parsing the json tree
  • alternatively, if you need more control: implement PrefabReader<JsonValue> (say because you want to different behavior on desktop vs mobile, e.g. non-caching vs caching)
• super.create() is wrapped in a prefab-specific method, aka createPlayer(x, y)
• https://github.com/junkdog/artemis-odb/issues/439 once done, deserialization is a (near) zero overhead operation.
  • this is the primary reason for the existence of @PrefabData; we need a straightforward approach for finding prefabs+json, and converting .json to .class.
  • it probably won't work with any esoteric custom PrefabReader<JsonValue> impl

mininmum viable world configuration:

world = new World(new WorldConfiguration()
    .setSystem(GroupManager.class) // not strictly necessary
    .setSystem(TagManager.class)   // not strictly necessary
    .setSystem(WorldSerializationManager.class));

JsonArtemisSerializer backend = new JsonArtemisSerializer(world);
backend.prettyPrint(true);
world.getSystem(WorldSerializationManager.class).setSerializer(backend);

saving entities to json

The (/some) tests use:

    public static String save(IntBag entities,
                              WorldSerializationManager manger)
            throws Exception {

        SaveFileFormat save = new SaveFileFormat(entities);
        ByteArrayOutputStream baos = new ByteArrayOutputStream(256);
        manger.save(baos, save);
        return baos.toString(StandardCharsets.UTF_8.name());
    }

[DaanVanYperen]

E("prefab/player.json").pos(5,5); AAAAAAAAAAAAAHHHHHHHHHHHHHH

[junkdog]

Whaaat1!?!!??