Class Stage

Stage is the container for all of the functionality for the playable portion of a game. Stage has several components:

  • The world, where all the action of the game happens
  • The heads-up display (HUD), where the user interface of the game is drawn.
  • The Score object
  • The background music and background color
  • The background and foreground parallax layers
  • The code for building, managing, and dismissing the win/lose/pause/welcome scenes

Stage is effectively a singleton: On any transition from one stage to another in the game, we don't make a new Stage object... instead we clear out the existing one and reuse it.

Stage does not manage transitions between scenes on its own. Instead, it has mechanisms (onScreenChange and endLevel) for resetting itself at the beginning of a stage, and cleaning itself up at the end of a stage.

Constructors

constructor

Properties

accelerometer background backgroundColor config console fontScaling foreground gameMusic gestures hud imageLibrary keyboard levelMusic musicLibrary network overlay? pixelMeterRatio platform renderer score screenHeight screenWidth storage svgScaling tilt world

Methods

begin clearOverlay exit renderHud renderOverlay renderWorld requestOverlay switchTo

Constructors

constructor

  • new Stage(config, domId, builder, platform): Stage

  • Set up the stage. This is the first step in starting a game.

    Parameters

    • config: JetLagGameConfig

      The game-wide configuration object

    • domId: string

      The Id of the DOM element where the game exists

    • builder: ((level) => void)

      A function for building the first visible level of the game

        • (level): void

        • Parameters

          • level: number

          Returns void

    • platform: PlatformDevice

      Platform-specific features

    Returns Stage

Properties

Readonly accelerometer

accelerometer: AccelerometerDevice

access to the the device's accelerometer

background

background: ParallaxSystem

The background layers

backgroundColor

backgroundColor: string = "#ffffff"

Background color for the stage being drawn. Defaults to white

Readonly config

config: JetLagGameConfig

The game-wide configuration object

Readonly console

console: ConsoleDevice

A console device, for debug messages

fontScaling

fontScaling: number = 1

Scaling ratio for fonts, relative to PPM4UF

foreground

foreground: ParallaxSystem

The foreground layers

gameMusic

gameMusic: undefined | MusicComponent

Background music that doesn't stop when the level changes

gestures

gestures: GestureDevice

touch controller, providing gesture inputs

hud

hud: Scene

A heads-up display

Readonly imageLibrary

imageLibrary: ImageLibraryService

A library of images

Readonly keyboard

keyboard: KeyboardDevice

keyboard controller, providing key event inputs

levelMusic

levelMusic: undefined | MusicComponent

Everything related to music that is controlled on one level at a time

Readonly musicLibrary

musicLibrary: AudioLibraryService

A library of sound and music files

Readonly network

network: NetworkDevice = ...

Network interface

Optional overlay

overlay?: Scene

Any pause, win, or lose scene that supersedes the world and hud

pixelMeterRatio

pixelMeterRatio: number = 0

The pixel-meter ratio (dummy value... gets computed early)

Readonly platform

platform: PlatformDevice

Platform-specific features

Readonly renderer

renderer: RendererDevice

rendering support, for drawing to the screen

Readonly score

score: ScoreService = ...

The Score, suitable for use throughout JetLag

screenHeight

screenHeight: number = 0

The screen height (dummy value... gets computed early)

screenWidth

screenWidth: number = 0

The screen width (dummy value... gets computed early)

Readonly storage

storage: StorageDevice

Persistent storage + volatile storage for a game session and a level

svgScaling

svgScaling: number = 1

The scaling ratio for SVG coords, relative to PPM4SVG

Readonly tilt

tilt: TiltService

The tilt system for the stage

world

world: Scene

The physics world in which all actors exist

Methods

begin

  • begin(): void

  • Load any images that need to be loaded, then launch the game. This is the last step in starting a game.

    Returns void

clearOverlay

  • clearOverlay(): void

  • Remove the current overlay scene, if any

    Returns void

exit

  • exit(): void

  • Close the window to exit the game

    Returns void

renderHud

  • renderHud(elapsedMs): void

  • This code is called dozens of times per second to update the game's hud's state and re-draw the hud

    Parameters

    • elapsedMs: number

      The time in milliseconds since the previous render

    Returns void

renderOverlay

  • renderOverlay(elapsedMs): void

  • Render the overlay if it exists. This code is called dozens of times per second to update the overlay, if it is being drawn.

    Parameters

    • elapsedMs: number

      The time in milliseconds since the previous render

    Returns void

renderWorld

  • renderWorld(elapsedMs): void

  • This code is called dozens of times per second to update the game's world's state and re-draw the world

    Parameters

    • elapsedMs: number

      The time in milliseconds since the previous render

    Returns void

requestOverlay

  • requestOverlay(builder, requestScreenshot): void

  • Request that an overlay be put on top of the game. This is not the HUD. It's something that goes on top of everything else, and prevents the game from playing, such as a pause scene, a win/lose scene, or a welcome scene.

    Parameters

    • builder: ((overlay, screenshot?) => void)

      Code for creating the overlay

        • (overlay, screenshot?): void

        • Parameters

          Returns void

    • requestScreenshot: boolean

      Should the overlay delay for a cycle or two, so a screenshot can be taken first?

    Returns void

switchTo

  • switchTo(builder, index): void

  • Before we call programmer code to load a new stage, we call this to ensure that everything is in a clean state.

    Parameters

    • builder: ((index, stage) => void)
        • (index, stage): void

        • Parameters

          • index: number
          • stage: Stage

          Returns void

    • index: number

    Returns void

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