System Class

The System class in EliCS is essential for implementing the logic that operates on entities and their components in the Entity-Component-System architecture. It enables efficient execution and management of application logic.

Features

• Lifecycle Management: Offers functionality to control the execution state of the system, such as playing or stopping.
• Execution Priority: Systems can be prioritized for execution order, where systems with lower priority numbers are executed first.
• Entity Processing: Acts as a framework where developers can define custom logic to query and process entities based on their components.

Usage

Defining a System

import { System, Query, Entity } from 'elics';

class YourSystem extends System {
	static queries = {
		yourQuery: {
			required: [
				/* required component types */
			],
			excluded: [
				/* optional excluded component types */
			],
		},
	};

	init() {
		// Initialization logic
	}

	update(delta: number, time: number) {
		// Update logic
		const entities = this.getEntities(YourSystem.queries.yourQuery);
		// Process entities
	}
}

const world = new World();
world.registerSystem(YourSystem);

Controlling System Lifecycle

const yourSystemInstance = world.getSystem(YourSystem);
yourSystemInstance.play();
yourSystemInstance.stop();

Properties

world

(Readonly) Access to the world instance.

• Type: World

isPaused

(Readonly) Indicates whether the system is currently paused.

• Type: boolean

queries

(Readonly) Queries registered in the system.

• Type: { [key: string]: Query }

priority

Execution priority of the system. Lower values indicate higher priority.

• Type: number

Methods

getEntities

Retrieves entities that match a given query.

getEntities(query: Query): Entity[]

• query: Query - The query to match entities against.
• Returns: Entity[] - An array of matching entities.

init

Initialization method for the system, executed immediately after the system is registered.

init(): void

update

The update method is called each frame and is intended to be overridden with custom logic.

update(delta: number, time: number): void

• delta: number - Delta time since the last update.
• time: number - Total time elapsed since the start of the application.

play

Resumes the execution of the system.

play(): void

stop

Pauses the execution of the system.

stop(): void