engn.js

Engn.js is a JS library to help you make your games in javascript. It is not a full-blown game engine, just a library to help you create one. It is licensed under the MIT license.

Note: All development must happen in the devel branch before being merged into master.

Everything is located in the engn namespace.

engn.trap (thing, container)

Trap the object thing inside of container. This moves thing to remain inside the bounds of container. Both thing and container are objects with x, y, width, and height properties.

engn.Loop (fps)

Establish a Loop object with the specified FPS for the loop. This is used for game loops.

onUpdate (callback)

Binds callback to be called whenever a game logic update (tick) occurs.

Returns: The original Loop object, to allow chaining

onRender (callback)

Binds callback to be called whenever a game rendering occurs.

Returns: The original Loop object, to allow chaining.

freeze ()

Freezes (pauses) the game loop at the next render.

Returns: The original Loop object, to allow chaining.

unfreeze ()

Unfreezes (plays) the game loop. This is also used to begin the game loop when it is first created.

Returns: The original Loop object, to allow chaining.

engn.checkIntersection (a, b)

Check for the intersection of rectangle a and rectangle b. a and b are objects with x, y, width, and height values.

Returns: A boolean value representing whether or not the rectangles intersect.

engn.makeDPad (container = document.body)

Create a game DPad and insert it into the given container. This is for use on touchscreen devices and the function will do nothing on non-touchscreens. The four arrows of the DPad are mapped to the keyboard arrow keys through engn.keys.

Default Styling/Appearance

The D-Pad looks like this:

It is positioned at the bottom center of the screen, overlaying other content. It is semi-transparent so that the content below it is visible.

Classes

• edpad - The D-Pad container.
• edpadup, edpaddown, edpadleft, edpadright - The up, down, left, and right buttons.
• edpadrow - A container for the edpadleft and edpadright elements.

engn.keys

A key monitor to determine which keys are pressed.

[keyname]

engn.keys[keyname] represents whether the key with that key name is pressed. The following keys are included:

• backspace
• tab
• enter
• shift
• ctrl
• alt
• pausebreak
• caps
• escape
• pgup
• pgdown
• end
• home
• left
• up
• right
• down
• insert
• delete
• 0
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• a
• b
• c
• d
• e
• f
• g
• h
• i
• j
• k
• l
• m
• n
• o
• p
• q
• r
• s
• t
• u
• v
• w
• x
• y
• z
• winleft
• winright
• select
• num0
• num1
• num2
• num3
• num4
• num5
• num6
• num7
• num8
• num9
• multiply
• add
• subtract
• decimal
• divide
• f1
• f2
• f3
• f4
• f5
• f6
• f7
• f8
• f9
• f10
• f11
• f12
• numlock
• scrolllock
• semicolon
• equals
• comma
• dash
• period
• slash
• grave accent
• openbracket
• backslash
• closebraket
• singlequote

reset ()

Reset the statuses of all keys.

noPreventDefault ()

Stop the key monitor from using preventDefault.

downEvt (e)

Trigger a simulated onkeydown event. e is an object with a keyCode property representing the key to be pressed.

upEvt (e)

Trigger a simulated onkeyup event. e is an object with a keyCode property representing the key to be released.

Returns: A boolean value representing whether or not the key is pressed.

bind (subject)

Detect keypresses for subject.

ignore (selector)

Ignore keypresses focused on this child element selector.