Canvas-simulator NPM

Simulator

A modern game and simulation library for the HTML Canvas element targeted for the use with ES6, TypeScript or Babel.

Getting Started

This library uses the modern ES6 class syntax, so before getting started you should learn to use tools like TypeScript or Babel to compile ES6 to ES5 or below.

You also should use tools like browserify or WebPack to bundle the library to use it in the browser.

If you want to learn more about the library, please have a look at the documentation.

Installation

$ npm i --save canvas-simulator

Creating the World

Everything that happens during the simulation or game is contained in a World which is created by creating a subclass which inherits from the World class. Our example world will be named NightSky.

// Import the World class from the library
import {World} from 'canvas-simulator';

// Create a new subclass
class NightSky extends World{
    // The constructor needs to be passed the Canvas 2D rendering context
    constructor(ctx){
        // Initiate the super class by passing the rendering context (you can forget about it now 🎉) and width and height of the canvas (optional)
        super(ctx, 400, 300);

        // Set background color
        super.setBackgroundColor('black');
    }
}


// Create a new new instance of the class

// Get context
let ctx = document.getElementById('canvas').getContext('2d');

//Initiate class
let sky = new NightSky(ctx);

Adding Life to the World

Now that the NightSky world is ready to use, we can add objects to it which are also instances of classes but which this time inherit from the Actor class of the library.

Here we create a subclass of the Actor class with the name of Bird.

// Import the Actor class from the library
import {Actor} from 'canvas-simulator';

class Bird extends Actor{
    constructor(){
        // Initiate the super class
        super();

        // Setup image
        this.setupImage();
    }

     private setupImage(){
        // Set image
        let url = 'https://api.tim-specht.com/data/simulator/tutorial/bird.png';
        super.setImageSrc(url);
    }
}

To add a bird to the NightSky world, you have to call the addToWorld method as follows in the NightSky class.

import {World} from 'canvas-simulator';

class NightSky extends World{

    constructor(ctx){
        super(ctx, 400, 300);
        super.setBackgroundColor('black');

        // Initiate new instance of Bird
        let bird = new Bird();

        // Add bird to world
        // super.addToWorld(<Actor>, <x>, <y>)

        super.addToWorld(bird, 50, 50);
    }
}

The whole script, after combining the imports properly, would look something like this, right now:

import {Actor, World} from 'canvas-simulator';

// Bird class
class Bird extends Actor{
    constructor(){
        super();
        this.setupImage();
    }

     private setupImage(){
        let url = 'https://api.tim-specht.com/data/simulator/tutorial/bird.png';
        super.setImageSrc(url);
    }
}

// NightSky class
class NightSky extends World{

    constructor(ctx){
        super(ctx, 400, 300);
        super.setBackgroundColor('black');
        let bird = new Bird();
        super.addToWorld(bird, 50, 50);
    }
}

// Initiate NightSky
let ctx = document.getElementById('canvas').getContext('2d');
let sky = new NightSky(ctx);

Animating!

To make the bird move, each Actor subclass can implement a method which is called animate (must be public). We can make our bird fly over the screen like this:

class Bird extends Actor{
    constructor(){
        super();
        this.setupImage();
    }

    public animate(){
        super.setX(super.getX() + 1);
    }

    private setupImage(){
        let url = 'https://api.tim-specht.com/data/simulator/tutorial/bird.png';
        super.setImageSrc(url);
    }
}

Now the bird moves quite slowly to the right of the screen.