import { Entity } from "./entities"; import { System } from "./systems"; export class Game { private systemOrder: string[]; private running: boolean; private lastTimeStamp: number; public entities: Map; public systems: Map; public componentEntities: Map>; constructor() { this.lastTimeStamp = performance.now(); this.running = false; this.systemOrder = []; this.systems = new Map(); this.entities = new Map(); this.componentEntities = new Map(); } public start() { this.lastTimeStamp = performance.now(); this.running = true; } public addEntity(entity: Entity) { this.entities.set(entity.id, entity); } public getEntity(id: string): Entity | undefined { return this.entities.get(id); } public removeEntity(id: string) { this.entities.delete(id); } public forEachEntityWithComponent( componentName: string, callback: (entity: Entity) => void, ) { this.componentEntities.get(componentName)?.forEach((entityId) => { const entity = this.getEntity(entityId); if (!entity) return; callback(entity); }); } public addSystem(system: System) { if (!this.systemOrder.includes(system.name)) { this.systemOrder.push(system.name); } this.systems.set(system.name, system); } public getSystem(name: string): System | undefined { return this.systems.get(name); } public doGameLoop(timeStamp: number) { if (!this.running) { return; } const dt = timeStamp - this.lastTimeStamp; this.lastTimeStamp = timeStamp; // rebuild the Component -> { Entity } map this.componentEntities.clear(); this.entities.forEach((entity) => entity.getComponents().forEach((component) => { if (!this.componentEntities.has(component.name)) { this.componentEntities.set( component.name, new Set([entity.id]), ); return; } this.componentEntities.get(component.name)?.add(entity.id); }), ); this.systemOrder.forEach((systemName) => { this.systems.get(systemName)?.update(dt, this); }); } }