README.md

TypeScript Render Engine

A super simple and lightweight TypeScript rendering engine for making 2D JavaScript games using HTML Canvases.

Usage | Installation | Examples | Documentation

Usage

Initialization

import Engine, { StaticLayer, IEntity } from '@zacktherrien/typescript-render-engine';

const engine = new Engine();

Creating layers

// create a new layer.
const backgroundZIndex = 0;
const backgroundLayer = new StaticLayer(backgroundZIndex);

// add the layer to the engine
engine.registerLayer(backgroundLayer);

Adding entities

// create an entity that extends the IEntity interface.
const terrain: IEntity = new Terrain(); // your class

// add the new entity to the layer
backgroundLayer.addEntity(terrain);

Start rendering

// render static background:
backgroundLayer.allowRenderOnNextFrame();

// start rendering dynamic layers
engine.start();

Installation

This package uses Github Packages as the NPM repository. See here for help.

Add the following to the .npmrc file at the root of your project's folder:

@zacktherrien:registry=https://npm.pkg.github.com

Then to install:

npm install @zacktherrien/typescript-render-engine

Examples

• Bouncing Square
• Pacman
• Boids

Documentation

Class: Engine

Methods

• start() Starts rendering the registered layers.
• stop() Stops rendering.
• registerLayer(layer: IRenderingLayer) Add a layer to the engine
  • layer The layer to be added
• getLayer(layerIndex: LayerIndex): IRenderingLayer Get a previous registered layer.
  • layerIndex a number representing the Z-Index of the layer.

Class: RenderingLayer

Properties

• readonly layerIndex: LayerIndex number representing the zindex of the layer

Methods

• constructor(layerIndex: LayerIndex, initialWidth?: number, initialHeight?: number, initialX: number = 0, initialY: number = 0,) Creates a rendering layer.
  • layerIndex Number representing the z-index of the layer on the screen.
  • entity An optional, default first entity of the layer.
• addEntity(entity: IEntity) Add an entity to be rendered
  • entity The entity to be added
• removeEntity(entity: IEntity) Remove an entity from being rendered
  • entity The entity to be deleted
• getContext(): CanvasRenderingContext2D Get the rendering context of this layer
• update(deltaTime: number) Updates all entities sequentially in the order they were added.
  • deltaTime Time (in ms) since the last frame was rendered
• render() Renders all the entities in this layer sequentially in the order they were added.
• getWidth(): number Get the width of the layer
• getHeight(): number Get the height of the layer
• getX(): number Get the x position of the layer, from the left side of the dom.
• getY(): number Get the y position of the layer, from the top of the dom.
• resize(width: number, height: number, resizeMethod: ResizeMethod = ResizeMethod.FROM_ORIGIN): number Change the size of the layer.
  • width The new width of the layer
  • height The new height of the layer
  • resizeMethod How the resize will be performed, from the origin or from the center of layer.
• setPosition(x: number, height: number) Change the position of the layer.
  • x the new x position of the layer.
  • y the new y position of the layer.

Class: DynamicLayer

Will update and render all entities in the layer when a new frame becomes available

Class: StaticLayer

Will render all entities in the layer when told via the allowRenderOnNextFrame function.

Methods

• allowRenderOnNextFrame() When the next frame becomes available, the render function will be called.

Class: DeferredLayer

Once the deferredTime (in MS) has been reached, the next frame will update and render. After another deferredTime the layer will update and rerender.

Methods

• constructor(deferredTime: number, layerIndex: LayerIndex, initialWidth?: number, initialHeight?: number, initialX: number = 0, initialY: number = 0,) Creates a deferred rendering layer.

Types

• RenderLayerFunction Function signature of a layer's render function.
• UpdateLayerFunction Function signature of a layer's update function.
• RenderFunction Function signature of an entity's render function.
• UpdateFunction Function signature of an entity's update function.
• LayerIndex Number representing the Z-Index of a layer.
• ResizeMethod Enum representing the resizing strategy of a layer
  • FROM_ORIGIN Resize the layer conserving the (0,0) point at the same position in the screen.
  • FROM_CENTER Resize the layer conserving the center point at the same position in the screen.

Recommended constants:

/**
 * Enum representing all layers' z-index.
 */
const enum LayerIndex {
    BACKGROUND = 0,
    HOUSES = 1,
    PLAYERS = 2,
    HUD = 10,
}