Elpy NPM | npm.io

Elpy.js - 2D JavaScript game engine.

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Demo	Game examples

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Install
Basic usage example
Engine
- create()
- add()
- key()
- keydown()
- keyup()
- mousemove()
- click()
- tick()
- nextTick()
- checkObjectInViewport()
- fixingCamera()
- unfixingCamera()
- destroy()
- on()
  - Event 'load'
  - Event 'animation'
- load()
Engine getters
Object
- run()
- move()
- fly()
- jump()
- fall()
- push()
- rotate()
- stop()
- destroy()
- collision()
- on()
  - Event 'collision'
  - Event 'move'
  - Event 'rotate'
  - Event 'destroy'
  - Event 'state'
  - Event 'jump'
  - Event 'fall'
  - Event 'fly'
  - Event object
- removeCollision()
Object getters
Object setters
Development
License

games

Install

Download

Latest builds are available in the project releases page.

CDN

https://unpkg.com/elpy/dist/elpy.min.js

NPM

npm install elpy

Basic usage example

<!DOCTYPE html>
<html>
<head>
  <title>Elpy.js</title>
</head>
<body>
  <canvas id="field"></canvas>
  <script src="elpy.min.js"></script>
  <script>
    const elpy = new Elpy('#field', 500, 500);
    const player = elpy.create('player', 50, 50, 20, 20);
    const wall = elpy.create('wall', 100, 50, 20, 20, { color: 'brown' });

    elpy.add(player);
    elpy.add(wall);
    player.collision(wall);

    elpy.key(key => {
      if (key === 'ArrowUp') {
        player.move(player.x, player.y - 1);
      }
      if (key === 'ArrowDown') {
        player.move(player.x, player.y + 1);
      }
      if (key === 'ArrowLeft') {
        player.move(player.x - 1, player.y);
      }
      if (key === 'ArrowRight') {
        player.move(player.x + 1, player.y);
      }
    });
  </script>
</body>
</html>

Engine

Create engine instance

const elpy = new Elpy(
  "#element", // id element canvas or HTML object element get by document.querySelector()
  500, // width
  500, // height
  // options
  {
    preload, // default - true, enable / disable preloader
    favicon // default - true, enable / disable favicon
  }
)

create(name, x, y, width, height, options)

name	type
`name`	`<String>`
`x`	`<Number>`
`y`	`<Number>`
`width`	`<Number>`
`height`	`<Number>`
`options`	`<Object>`

Creates and returns an engine object.

min example

const player = elpy.create('player', 10, 10, 20, 20);

max example

const player = elpy.create('player', 10, 10, 20, 20, {
  obstacle: true, // default - true
  pushing: false, // default - false
  disabledEvents: false, // default - false
  type: 'player object', // default - null
  custom: {}, // default - null
  color, // default - 'black'
  // image: '' or image: { src: '', repeat: false }
  image: { 
    src: '', // default - null
    repeat: false // default - false
  },
  // default - null
  images: [
    {
      paths: ['images/player_left.png', 'images/player_right.png'], // path to image.
      state: 'move:left', // in what condition are the images available. player.state = 'move:left'.
      time: 100 // if player.animate = true - switching time between images.
    }
  ]
});

name	description
`obstacle`	To determine if an object is an obstacle if there is a collision with the object. If the object was not added to the collision then the object will pass through another object. If an object has been added to a collision, then by default the object will stop on collision. If it is necessary that the collision event occur and the object passes through the object, then the obstacle property can be switched to false.
`pushing`	Will the object move if it is pushed through the push method.
`disabledEvents`	Disables all events for an object.
`type`	A simple string that allows you to add your own data. It is convenient to use to set the type of an object in order to distinguish them from each other later.
`custom`	An object where you can add your fields and use them via `object.options.custorm`.
`color`	Set object color.
`image`	Set image. Two data types can be used: String or Object. `image: 'path/to/image/'` or for repeat image `image: { src: 'path/to/image/', repeat: true }`
`images`	Can be used if the object has several images that can be changed through the state. For example, the image of the position when the player goes to the right or left. You can also make animation of switching frames through the animate property (Object getters). The switching `time` is set in the time property.

add(object)

name	type
`object`	`<String>`

Add an object to the engine.

elpy.add(player);

key(callback)

name	type
`callback`	`<Function>`

Listen for keydown and keyup events. Сallback is always called when a key is pressed.

elpy.key(key => {
  if (key === 'ArrowUp') {
    // ...
  }
});

keydown(callback)

name	type
`callback`	`<Function>`

Сallback fires once on click.

elpy.keydown(key => {
  if (key === 'ArrowUp') {
    // ...
  }
});

keyup(callback)

name	type
`callback`	`<Function>`

Сallback fires once on click.

elpy.keyup(key => {
  if (key === 'ArrowUp') {
    // ...
  }
});

mousemove(callback)

name	type
`callback`	`<Function>`

Handles mouse movement on the canvas.

elpy.mousemove((x, y) => {
  // x, y - coordinates inside the canvas.
});

click(callback)

name	type
`callback`	`<Function>`

Handles mouse click on the canvas.

elpy.click((x, y) => {
  // x, y - coordinates inside the canvas.
});

tick(callback)

name	type
`callback`	`<Function>`

Called recursively. The next call is queued after the scene is updated (render). To cancel the call inside the callback, return false.

let delta = 0;
// tick will be called 100 times
elpy.tick(() => {
  if (delta === 100) {
    return false; // stop tick
  }

  delta++;
  
  player.move(player.x + delta, player.y + delta);
});

nextTick(callback)

name	type
`callback`	`<Function>`

Adds a callback to the queue after the scene is updated (rendered) and calls callback once.

elpy.nextTick(() => {
  // ...
});

checkObjectInViewport(object)

name	type
`object`	`<Object>`

Checking if the object is in the visible area.

elpy.checkObjectInViewport(player); // returns true or false

fixingCamera(object, fixedCamera)

name	type
`object`	`<Object>`
`fixedCamera`	`<Object>`

Fix the camera behind the object. You can fix both in one coordinate and in two.

min example

elpy.fixingCamera(player, {
  x: true
});

max example

elpy.fixingCamera(player, {
  x: true,
  y: true
});

unfixingCamera()

Unfix the camera from the one previously fixed behind the object.

elpy.unfixingCamera();

destroy()

Destroying all objects and stopping rendering.

elpy.destroy();

on(event, callback)

name	type
`event`	`<String>`
`callback`	`<Function>`

Listen to the engine event.

elpy.on('eventName', () => {
  // Event handling.
});

Event: `'load'`

elpy.on('load', () => {
  // Event handling.
});

Event: `'animation'`

elpy.on('animation', (object, image, images) => {
  // object - object to be animated.
  // image - current image. Examlpe: 'images/player_left.png'
  // images - a list of all images that were passed to paths when the object was created. Example: ['images/player_left.png', 'images/player_right.png']
});

load()

The method is called automatically when document.readyState === 'complete'. If the engine has not loaded and is in a black window state, you can call load manually after all operations with the engine (creating objects, adding objects, etc.).

elpy.load();

Engine getters

min example

elpy.width;

name	type	description
width	`<Number>`	Returns the width of the canvas.
height	`<Number>`	Returns the height of the canvas.
offset	`<Object>`	Returns information on object and field offset.
objects	`<Object>`	Returns all added objects.

Object

run(step)

name	type	default
`step`	`<Number>`	`1`

Vector movement. Moves in different directions depending on positive or negative values.

min example

player.run();

max example

player.run(-1);

move(x, y)

name	type
`x`	`<Number>`
`y`	`<Number>`

Move at coordinates.

player.move(10, 10);

fly(degrees, distance, step)

name	type	default
`degrees`	`<Number>`
`distance`	`<Number>`	`0`
`step`	`<Number>`	`1`

Vector flight.

min example

player.fly(0);

max example

player.fly(0, 100, 10);

jump(height, multiplier, forced)

name	type	default
`height`	`<Number>`
`multiplier`	`<Number>`	`0.1`
`forced`	`<Boolean>`	`false`

min example

player.jump(10);

max example

player.jump(10, 0.5, true);

fall(multiplier)

name	type	default
`multiplier`	`<Number>`	`0.1`

Free fall.

min example

player.fall();

max example

player.fall(0.5);

push(object)

name	type
`object`	`<Object>`

Pushing an object. The one who pushes must have a collision with what he pushes.

player.push(object);

rotate(degrees, x, y)

name	type	default
`degrees`	`<Number>`
`x`	`<Number>`	`0`
`y`	`<Number>`	`0`

Object rotation.

min example

player.rotate(90);

max example

player.rotote(90, 10, 20);

stop()

Stop: jump, fall, fly.

player.stop();

destroy()

Destroy object.

player.destroy();

collision(object)

name	type
`object`	`<Object>`, `<Array>`

Add collision object.

player.collision(object);

on(event, callback)

name	type
`event`	`<String>`
`callback`	`<Function>`

Add an event listener.

player.on('eventName', () => {
  // Event handling.
});

Event: `'collision'`

Callback arguments.

name	type
`object`	`<Object>`
`side`	`<String>`

player.on('collision', (object, side) => {
  // object - collision object.
  // side - side of the object that was collided.
});

Event: `'move'`

player.on('move', () => {
  // Event handling.
});

Event: `'rotate'`

player.on('rotate', () => {
  // Event handling.
});

Event: `'destroy'`

player.on('destroy', () => {
  // Event handling.
});

Event: `'state'`

player.on('state', () => {
  // Event handling.
});

Event: `'jump'`

Callback arguments.

name	type	description
`event`	`<Object>`	link

player.on('jump', event => {
  // event - event object.
});

Event: `'fall'`

Callback arguments.

name	type	description
`event`	`<Object>`	link

player.on('fall', event => {
  // event - event object.
});

Event: `'fly'`

Callback arguments.

name	type	description
`event`	`<Object>`	link

player.on('fly', event => {
  // event - event object.
});

Event object

The object that is returned in the event callback: jump, fall, fly.

name	type	description
`stopped`	`<Boolean>`	The property will be `true` if the object has been stopped.
`paused`	`<Boolean>`	The property will be `true` if the object has been paused.
`stop()`		Stop object. If he was in a state: `jump`, `fall`, `fly`.
`pause()`		Pause object. If he was in a state: `jump`, `fall`, `fly`.
`resume()`		Resume object. If it was paused.

player.on('jump', event => {
  event.stopped; // returns true or false
  event.paused; // returns true or false
  event.stop();
  event.pause();
  event.resume();
});

removeCollision(object)

name	type
`object`	`<Object>`

Remove collision object from collision list.

player.removeCollision(object);

Object getters

min example

player.name;

name	type	description
name	`<String>`	Returns the name of the object.
options	`<Object>`	Returns object options.
track	`<Object>`	Returns the object's previous moves.
dest	`<Object>`	Returns the coordinates where the object is moving.
offset	`<Object>`	Returns the offset coordinates of an object.
isPushing	`<Boolean>`	Is it possible to push an object.
isJumping	`<Boolean>`	Is the object in a jump.
isFlying	`<Boolean>`	Is the object in fly.
isExist	`<Boolean>`	Does the object exist.
x	`<Number>`
y	`<Number>`
width	`<Number>`
height	`<Number>`
state	`<String>`	Returns the current state of the object.
animate	`<Boolean>`	Is the object animated.
ghost	`<Boolean>`	Whether collision is canceled with other objects that go to it.
degrees	`<Number>`
added	`<Boolean>`	Is the object added.

Object setters

min example

player.width = 10;

name	type	description
x	`<Number>`
y	`<Number>`
width	`<Number>`
height	`<Number>`
state	`<String>`	Used to switch textures.
animate	`<Boolean>`	Whether to animate the object.
ghost	`<Boolean>`	Cancels collision with other objects that go to it.
added	`<Boolean>`	Is the object added.