Global

Members

(constant) canvas :HTMLCanvasElement

Canvas API
Type:
  • HTMLCanvasElement
Source:

(constant) ctx :CanvasRenderingContext2D

Canvas's context
Type:
  • CanvasRenderingContext2D
Source:

(constant) images :Object

A dictionary of images whose keys are the same as Sprite types
Type:
  • Object
Source:

(constant) inputStates :Object

Local object used by handlers to message the loop
Type:
  • Object
Properties:
Name Type Description
inputStates.isUp Boolean Up arrow pressed or not
inputStates.isThrust Boolean Don't want to add more rocket noise 60 times a second
inputStates.isLeft Boolean Left arrow pressed or not
inputStates.isRight Boolean Right arrow pressed or not
inputStates.isSpace Boolean Space arrow pressed or not
inputStates.isLoaded Boolean Space bar needs to be released between missiles
Source:

(constant) state :Object

The animation loop and event handlers communicate via this global object
Type:
  • Object
Properties:
Name Type Description
sprites Array.<Sprite> spaceship and 12 asteroids in list
Source:

Methods

animationLoop() → {undefined}

The thing that freezes Jasmine to make this untestable
Source:
Returns:
Never returning infinite loop
Type
undefined

createAsteroid() → {Sprite}

Initialises an asteroid Sprite
Source:
Returns:
Selects random start (not on top of spaceship), speed and rotation
Type
Sprite

createMissile() → {Sprite}

Initialises a missile Sprite, shoots from tip of spaceship
Source:
Returns:
Missile shot from spaceship, lives 2 seconds (120 ticks)
Type
Sprite

createSpaceship() → {Sprite}

Initialises a spaceship Sprite
Source:
Returns:
A spaceship starting in the centre, facing up, stationary
Type
Sprite

draw(sprite) → {undefined}

Uses five of CanvasRenderingContext2D's many methods
Parameters:
Name Type Description
sprite Sprite The 9 parameters needed by ctx.drawImage, the 2 for ctx.translate, and angle for ctx.rotate
Source:
Returns:
Causes side-effect of drawing image
Type
undefined

getScale(windowWidth, windowHeight, BASE_WIDTH, BASE_HEIGHT) → {float}

Calculate a ratio to make the canvas larger for big screens, smaller for mobile devices
Parameters:
Name Type Description
windowWidth pixels - originally hardwired to window.innerWidth
windowHeight pixels - originally hardwired to window.innerHeight
BASE_WIDTH pixels - originally hardwired to backgroundImage.width
BASE_HEIGHT pixels - originally hardwired to backgroundImage.height
Source:
Returns:
Amount to multiply the sizes of images
Type
float

nextTick(sprite) → {undefined}

The physics/game engine
Parameters:
Name Type Description
sprite Sprite Position and movement parameters to be updated
Source:
Returns:
Mutates the sprite object
Type
undefined

playSound(soundName) → {buffer}

Public function to use sound objects
Parameters:
Name Type Description
soundName "background" | "explosion" | "missile" | "thrust" | "backgroundStop" | "thrustStop" key in sounds dictionary
Source:
Returns:
Return object needed to turn thrust sound off
Type
buffer

resizeListener() → {undefined}

The resizeListener event handler
Source:
Returns:
Mutates the scale attribute of
Type
undefined

uiListener(event) → {undefined}

The user input event handler
Parameters:
Name Type Description
event KeyboardEvent | PointerEvent Object sent by target.addEventListener(type, (event) => uiListener(inputStates, event));
Properties:
Name Type Description
event.type DOMString Inherited from Event
event.key DOMString A Key Value
event.target DOMString document since that's what called this function
Source:
Returns:
Mutates the inputStates global object
Type
undefined

Type Definitions

sounds

Dictionary of sound objects
Type:
  • Object
Properties:
Name Type Description
audioNode buffer Binary blobs from sound files
Source: