WGBH SpringRoll Game Library

Framework for building 2D games using SpringRoll 2 and Pixi.js

Peer Dependencies

The following modules must be included alongside this one in your project:

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For integration into standard PBS game container

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2D WebGL renderer with Context2D fallback

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WebAudio sound loading/playback system with HTML5 Audio fallback

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For loading and playback of content exported from Adobe Animate via the PixiAnimate Extension

Framework Philosophy

To reduce the need for an individual SpringRoll game project to address the issues of browser compatibility and container integration, and to provide a structure and set of tools likely to be useful for all SpringRoll games

This framework is based around a concept of one Game being a collection of Scenes. A Game serves to bind the various integration/management classes and the Scenes together. Only one Scene is active at a time, and at any given time, the currently active Scene is responsible for all interactions, game behavior, display, etc.

Project Setup

Your project should contain a class which extends this library's Game class, and one or more classes which extend this library's Scene class. Override the Game's gameReady function, therein calling this.addScenes(), passing in an object mapping the classes of each of your game's Scenes to string IDs which will be used to reference them later. Then call this.changeScene(), passing in the ID of your initial Scene. Instantiate your Game class at the root of your source, passing in desired game options, including a transition which is a reference to a PixiAnimate stage class for the transition animation, and a containerID which matches the ID of the HTML element which should contain your game's Canvas element. See WGBH SpringRoll Game Template for project setup example.

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A Scene is an extension of PIXI.Container and also contains the following functions which should, in most cases, be overridden in your implementation. They are called in sequential order over the course of the Scene's active lifecycle:

#### preload():AssetList
This method should return an array of AssetDescriptor objects, specifying the types, IDs, and paths for files to be loaded before entering this Scene.

#### setup()
This method is called once all assets specified in preload() have completed loading. At this time, your Scene should create and add any children which should be visible upon transitioning in.

#### start()
This method is called when the transition-in is complete, fully revealing the contents of this Scene. Start this Scene's behavior sequence here.

#### update(deltaTime:number)
This method is called on each tick of the render loop (target: 60FPS), starting just after start() is called. The deltaTime value passed in represents the actual time since the previous frame, in milliseconds.

#### changeScene(nextScene:string)
Do not override this method. This method should be called to transition out of this Scene and into the next. A valid ID for the next scene must be passed in.

#### cleanup()
This method is called at the end of a transition out of this Scene. At this time, the transition should be covering the screen, hiding the contents of this Scene, unneeded references to objects in memory should be cleaned up, and any children added to the display should be removed in preparation for their assets to be unloaded and this Scene to be destroyed.