Game states and main menu

common/ecs/world.ts

@@ -2,33 +2,79 @@ import type { Entity } from "./entity.ts";
 import type { System } from "./system.ts";
 
 export class World {
-	entities = new Set<Entity>();
-	systems = new Set<System>();
-	tags = new Map<string, Entity[]>();
+	#entities = new Set<Entity>();
+	#entities_for_deletion = new Set<Entity>();
 
-	add_entity(entity: Entity) {
-		this.entities.add(entity);
+	#systems = new Map<string, Set<System>>();
+	#tags = new Map<string, Entity[]>();
+	#states = new Set<string>();
+
+	#state: string = "";
+	#new_state: string | undefined;
+
+	constructor(initial_state: string) {
+		this.#state = initial_state;
+		this.add_state("*");
 	}
 
-	add_system(system: System) {
-		this.systems.add(system);
+	add_state(new_state: string) {
+		this.#states.add(new_state);
+		this.#systems.set(new_state, new Set());
+	}
+
+	add_entity(entity: Entity) {
+		this.#entities.add(entity);
+	}
+
+	add_system(system: System, state: string) {
+		console.assert(this.#states.has(state));
+		this.#systems.get(state)!.add(system);
 	}
 
 	add_tag(tag: string, entities: Entity[]) {
-		this.tags.set(tag, entities);
+		this.#tags.set(tag, entities);
 	}
 
 	get_tag(tag: string) {
-		return this.tags.get(tag);
+		return this.#tags.get(tag);
 	}
 
 	update(delta: number) {
-		for (const system of this.systems) {
+		for (const system of this.#systems.get("*") ?? []) {
 			system.update(this, delta);
 		}
+		for (const system of this.#systems.get(this.#state) ?? []) {
+			system.update(this, delta);
+		}
+		// should be faster than Set.prototype.difference lol
+		for (const entity of this.#entities_for_deletion) {
+			this.#entities.delete(entity);
+		}
+		if (this.#new_state) {
+			this.#state = this.#new_state;
+			this.#new_state = undefined;
+		}
 	}
 
 	get_entities() {
-		return this.entities;
+		return this.#entities;
+	}
+
+	delete_entity(entity: Entity) {
+		this.#entities_for_deletion.add(entity);
+	}
+
+	clear_entities() {
+		for (const entity of this.#entities) {
+			this.#entities_for_deletion.add(entity);
+		}
+	}
+
+	get state() {
+		return this.#state;
+	}
+
+	set state(new_state: string) {
+		this.#new_state = new_state;
 	}
 }