added resource culling and resource saving in the ResourceManager

src/Wolfie2D/AI/StateMachineAI.ts

@@ -1,6 +1,5 @@
 import AI from "../DataTypes/Interfaces/AI";
 import StateMachine from "../DataTypes/State/StateMachine";
-import GameEvent from "../Events/GameEvent";
 import GameNode from "../Nodes/GameNode";
 
 /**
@@ -17,6 +16,7 @@ export default class StateMachineAI extends StateMachine implements AI {
 	destroy(){
 		// Get rid of our reference to the owner
 		delete this.owner;
+		this.receiver.destroy();
 	}
 
 	// @implemented

src/Wolfie2D/DataTypes/Interfaces/Physical.ts

@@ -13,6 +13,9 @@ export default interface Physical {
     /** Represents whether the object is moving or not. */
     moving: boolean;
 
+    /** Represent whether the object is frozen from moving or not. */
+    frozen: boolean;
+
     /** Represents whether the object is on the ground or not. */
     onGround: boolean;
 

src/Wolfie2D/DataTypes/Queue.ts

@@ -37,7 +37,7 @@ export default class Queue<T> implements Collection {
      */
     enqueue(item: T): void{
         if((this.tail + 1) % this.MAX_ELEMENTS === this.head){
-            throw "Queue full - cannot add element"
+            throw new Error("Queue full - cannot add element");
         }
 
         this.size += 1;
@@ -51,7 +51,7 @@ export default class Queue<T> implements Collection {
      */
     dequeue(): T {
         if(this.head === this.tail){
-            throw "Queue empty - cannot remove element"
+            throw new Error("Queue empty - cannot remove element");
         }
 
 

src/Wolfie2D/DataTypes/Stack.ts

@@ -5,7 +5,7 @@ import Collection from "./Collection";
  */
 export default class Stack<T> implements Collection {
     /** The maximum number of elements in the Stack */
-    private readonly MAX_ELEMENTS: number;
+    private MAX_ELEMENTS: number;
     
     /** The internal representation of the stack */
     private stack: Array<T>;

src/Wolfie2D/Events/EventQueue.ts

@@ -81,7 +81,7 @@ export default class EventQueue {
     unsubscribe(receiver: Receiver, ...events: Array<string>): void {
         this.receivers.forEach(eventName => {
             // If keys were provided, only continue if this key is one of them
-            if(events !== undefined && events.indexOf(eventName) === -1) return;
+            if(events.length > 0 && events.indexOf(eventName) === -1) return;
 
             // Find the index of our receiver for this key
             let index = this.receivers.get(eventName).indexOf(receiver);

src/Wolfie2D/Events/Receiver.ts

@@ -36,7 +36,12 @@ export default class Receiver {
 	 * @param event The event to receive
 	 */
 	receive(event: GameEvent): void {
+		try{
 		this.q.enqueue(event);
+		} catch(e){
+			console.warn("Receiver overflow for event " + event.toString());
+			throw e;
+		}
 	}
 
 	/**

src/Wolfie2D/Nodes/GameNode.ts

@@ -33,6 +33,7 @@ export default abstract class GameNode implements Positioned, Unique, Updateable
 	/*---------- PHYSICAL ----------*/
 	hasPhysics: boolean = false;
 	moving: boolean = false;
+	frozen: boolean = false;
 	onGround: boolean = false;
 	onWall: boolean = false;
 	onCeiling: boolean = false;
@@ -151,11 +152,13 @@ export default abstract class GameNode implements Positioned, Unique, Updateable
      * @param velocity The velocity with which to move the object.
      */
 	move(velocity: Vec2): void {
+		if(this.frozen) return;
 		this.moving = true;
 		this._velocity = velocity;
 	};
 
 	moveOnPath(speed: number, path: NavigationPath): void {
+		if(this.frozen) return;
 		this.path = path;
 		let dir = path.getMoveDirection(this);
 		this.moving = true;
@@ -230,6 +233,9 @@ export default abstract class GameNode implements Positioned, Unique, Updateable
 
 	/** Removes this object from the physics system */
     removePhysics(): void {
+		// Remove this from the physics manager
+		this.scene.getPhysicsManager().deregisterObject(this);
+
 		// Nullify all physics fields
 		this.hasPhysics = false;
 		this.moving = false;
@@ -250,9 +256,16 @@ export default abstract class GameNode implements Positioned, Unique, Updateable
 		this.collisionShape = null;
 		this.colliderOffset = Vec2.ZERO;
 		this.sweptRect = null;
+	}
 
-		// Remove this from the physics manager
+	/** Disables physics movement for this node */
-		this.scene.getPhysicsManager().deregisterObject(this);
+	freeze(): void {
+		this.frozen = true;
+	}
+
+	/** Reenables physics movement for this node */
+	unfreeze(): void {
+		this.frozen = false;
 	}
 
     /** Prevents this object from participating in all collisions and triggers. It can still move. */

src/Wolfie2D/Nodes/UIElement.ts

@@ -90,7 +90,6 @@ export default abstract class UIElement extends CanvasNode {
 				}
 				if(this.onClickEventId !== null){
 					let data = {};
-					console.log("Click event: " + this.onClickEventId)
 					this.emitter.fireEvent(this.onClickEventId, data);
 				}
 			}

src/Wolfie2D/Physics/BasicPhysicsManager.ts

@@ -72,7 +72,6 @@ export default class BasicPhysicsManager extends PhysicsManager {
 	 * @param options A record of options
 	 */
 	protected parseOptions(options: Record<string, any>): void {
-		console.log("Parsing physics options: ", options);
 		if(options.groupNames !== undefined && options.collisions !== undefined){
 			for(let i = 0; i < options.groupNames.length; i++){
 				let group = options.groupNames[i];
@@ -108,6 +107,7 @@ export default class BasicPhysicsManager extends PhysicsManager {
 
 	// @override
 	deregisterObject(node: Physical): void {
+		console.log("Deregistering physics object");
 		if(node.isStatic){
 			// Remove the node from the static list
 			const index = this.staticNodes.indexOf(node);

src/Wolfie2D/Physics/PhysicsManager.ts

@@ -33,6 +33,10 @@ export default abstract class PhysicsManager implements Updateable {
 		this.groupNames = new Array();
 	}
 
+	destroy(): void {
+		this.receiver.destroy();
+	}
+
 	/**
 	 * Registers a gamenode with this physics manager
 	 * @param object The object to register

src/Wolfie2D/ResourceManager/ResourceManager.ts

@@ -81,7 +81,6 @@ export default class ResourceManager {
     private loadonly_gl_ShaderProgramsToLoad: number;
     private loadonly_gl_ShaderLoadingQueue: Queue<KeyPath_Shader>;
 
-    private gl_DefaultShaderPrograms: Map<WebGLProgramType>;
     private gl_ShaderPrograms: Map<WebGLProgramType>;
 
     private gl_Textures: Map<number>;
@@ -90,6 +89,13 @@ export default class ResourceManager {
 
     private gl: WebGLRenderingContext;
 
+    /* ########## UNLOADING AND EXCLUSION LIST ########## */
+    /** A list of resources that will be unloaded at the end of the current scene */
+    private resourcesToUnload: Array<ResourceReference>;
+
+    /** A list of resources to keep until further notice */
+    private resourcesToKeep: Array<ResourceReference>;
+
     private constructor(){
         this.loading = false;
         this.justLoaded = false;
@@ -123,14 +129,17 @@ export default class ResourceManager {
         this.loadonly_gl_ShaderProgramsToLoad = 0;
         this.loadonly_gl_ShaderLoadingQueue = new Queue();
 
-        this.gl_DefaultShaderPrograms = new Map();
         this.gl_ShaderPrograms = new Map();
 
         this.gl_Textures = new Map();
         this.gl_NextTextureID = 0;
         this.gl_Buffers = new Map();
+
+        this.resourcesToUnload = new Array();
+        this.resourcesToKeep = new Array();
     };
 
+    /* ######################################## SINGLETON ########################################*/
     /**
      * Returns the current instance of this class or a new instance if none exist
      * @returns The resource manager
@@ -143,6 +152,7 @@ export default class ResourceManager {
         return this.instance;
     }
 
+    /* ######################################## PUBLIC FUNCTION ########################################*/
     /**
      * Activates or deactivates the use of WebGL
      * @param flag True if WebGL should be used, false otherwise
@@ -165,6 +175,14 @@ export default class ResourceManager {
         this.loadonly_imageLoadingQueue.enqueue({key: key, path: path});
     }
 
+    /**
+     * Tells the resource manager to keep this resource
+     * @param key The key of the resource
+     */
+    public keepImage(key: string): void {
+        this.keepResource(key, ResourceType.IMAGE);
+    }
+
     /**
      * Retrieves a loaded image
      * @param key The key of the loaded image
@@ -187,6 +205,14 @@ export default class ResourceManager {
         this.loadonly_spritesheetLoadingQueue.enqueue({key: key, path: path});
     }
 
+    /**
+     * Tells the resource manager to keep this resource
+     * @param key The key of the resource
+     */
+    public keepSpritesheet(key: string): void {
+        this.keepResource(key, ResourceType.SPRITESHEET);
+    }
+
     /**
      * Retrieves a loaded spritesheet
      * @param key The key of the spritesheet to load
@@ -205,6 +231,14 @@ export default class ResourceManager {
         this.loadonly_audioLoadingQueue.enqueue({key: key, path: path});
     }
 
+    /**
+     * Tells the resource manager to keep this resource
+     * @param key The key of the resource
+     */
+     public keepAudio(key: string): void {
+        this.keepResource(key, ResourceType.AUDIO);
+    }
+
     /**
      * Retrieves a loaded audio file
      * @param key The key of the audio file to load
@@ -223,6 +257,14 @@ export default class ResourceManager {
         this.loadonly_tilemapLoadingQueue.enqueue({key: key, path: path});
     }
 
+    /**
+     * Tells the resource manager to keep this resource
+     * @param key The key of the resource
+     */
+     public keepTilemap(key: string): void {
+        this.keepResource(key, ResourceType.TILEMAP);
+    }
+
     /**
      * Retreives a loaded tilemap
      * @param key The key of the loaded tilemap
@@ -241,6 +283,14 @@ export default class ResourceManager {
         this.loadonly_jsonLoadingQueue.enqueue({key: key, path: path});
     }
 
+    /**
+     * Tells the resource manager to keep this resource
+     * @param key The key of the resource
+     */
+     public keepObject(key: string): void {
+        this.keepResource(key, ResourceType.JSON);
+    }
+
     /**
      * Retreives a loaded object
      * @param key The key of the loaded object
@@ -250,6 +300,7 @@ export default class ResourceManager {
         return this.jsonObjects.get(key);
     }
 
+    /* ######################################## LOAD FUNCTION ########################################*/
     /**
      * Loads all resources currently in the queue
      * @param callback The function to cal when the resources are finished loading
@@ -293,6 +344,21 @@ export default class ResourceManager {
         callback();
     }
 
+    /* ######################################## UNLOAD FUNCTION ########################################*/
+    
+    private keepResource(key: string, type: ResourceType): void {
+        console.log("Keep resource...");
+        for(let i = 0; i < this.resourcesToUnload.length; i++){
+            let resource = this.resourcesToUnload[i];
+            if(resource.key === key && resource.resourceType === type){
+                console.log("Found resource " + key + " of type " + type + ". Keeping.");
+                let resourceToMove = this.resourcesToUnload.splice(i, 1);
+                this.resourcesToKeep.push(...resourceToMove);
+                return;
+            }
+        }
+    }
+    
     /**
      * Deletes references to all resources in the resource manager
      */
@@ -300,29 +366,46 @@ export default class ResourceManager {
         this.loading = false;
         this.justLoaded = false;
 
-        this.loadonly_imagesLoaded = 0;
+        for(let resource of this.resourcesToUnload){
-        this.loadonly_imagesToLoad = 0;
+            // Unload the resource
-        this.images.clear();
+            this.unloadResource(resource);
-
+        }
-        this.loadonly_spritesheetsLoaded = 0;
-        this.loadonly_spritesheetsToLoad = 0;
-        this.spritesheets.clear();
-
-        this.loadonly_tilemapsLoaded = 0;
-        this.loadonly_tilemapsToLoad = 0;
-        this.tilemaps.clear();
-
-        this.loadonly_audioLoaded = 0;
-        this.loadonly_audioToLoad = 0;
-        this.audioBuffers.clear();
-
-        // WebGL
-        // Delete all programs through webGL
-        this.gl_ShaderPrograms.forEach(key => this.gl_ShaderPrograms.get(key).delete(this.gl));
-        this.gl_ShaderPrograms.clear();
-        this.gl_Textures.clear();
     }
 
+    private unloadResource(resource: ResourceReference): void {
+        // Delete the resource itself
+        switch(resource.resourceType){
+            case ResourceType.IMAGE:
+                this.images.delete(resource.key);
+                if(this.gl_WebGLActive){
+                    this.gl_Textures.delete(resource.key);
+                }
+                break;
+            case ResourceType.TILEMAP:
+                this.tilemaps.delete(resource.key);
+                break;
+            case ResourceType.SPRITESHEET:
+                this.spritesheets.delete(resource.key);
+                break;
+            case ResourceType.AUDIO:
+                this.audioBuffers.delete(resource.key);
+                break;
+            case ResourceType.JSON:
+                this.jsonObjects.delete(resource.key);
+                break;
+            case ResourceType.SHADER:
+                this.gl_ShaderPrograms.get(resource.key).delete(this.gl);
+                this.gl_ShaderPrograms.delete(resource.key);
+                break;
+        }
+
+        // Delete any dependencies
+        for(let dependency of resource.dependencies){
+            this.unloadResource(dependency);
+        }
+    }
+
+    /* ######################################## WORK FUNCTIONS ########################################*/
     /**
      * Loads all tilemaps currently in the tilemap loading queue
      * @param onFinishLoading The function to call when loading is complete
@@ -355,22 +438,32 @@ export default class ResourceManager {
             
             // We can parse the object later - it's much faster than loading
             this.tilemaps.add(key, tilemapObject);
+            let resource = new ResourceReference(key, ResourceType.TILEMAP);
 
             // Grab the tileset images we need to load and add them to the imageloading queue
             for(let tileset of tilemapObject.tilesets){
                 if(tileset.image){
                     let key = tileset.image;
                     let path = StringUtils.getPathFromFilePath(pathToTilemapJSON) + key;
-                    this.loadonly_imageLoadingQueue.enqueue({key: key, path: path});
+                    this.loadonly_imageLoadingQueue.enqueue({key: key, path: path, isDependency: true});
+
+                    // Add this image as a dependency to the tilemap
+                    resource.addDependency(new ResourceReference(key, ResourceType.IMAGE));
                 } else if(tileset.tiles){
                     for(let tile of tileset.tiles){
                         let key = tile.image;
                         let path = StringUtils.getPathFromFilePath(pathToTilemapJSON) + key;
-                        this.loadonly_imageLoadingQueue.enqueue({key: key, path: path});
+                        this.loadonly_imageLoadingQueue.enqueue({key: key, path: path, isDependency: true});
+
+                        // Add this image as a dependency to the tilemap
+                        resource.addDependency(new ResourceReference(key, ResourceType.IMAGE));
                     }
                 }
             }
 
+            // Add the resource reference to the list of resource to unload
+            this.resourcesToUnload.push(resource);
+
             // Finish loading
             this.finishLoadingTilemap(callbackIfLast);
         });
@@ -422,9 +515,14 @@ export default class ResourceManager {
             // We can parse the object later - it's much faster than loading
             this.spritesheets.add(key, spritesheet);
 
+            let resource = new ResourceReference(key, ResourceType.SPRITESHEET);
+
             // Grab the image we need to load and add it to the imageloading queue
             let path = StringUtils.getPathFromFilePath(pathToSpritesheetJSON) + spritesheet.spriteSheetImage;
-            this.loadonly_imageLoadingQueue.enqueue({key: spritesheet.name, path: path});
+            this.loadonly_imageLoadingQueue.enqueue({key: spritesheet.name, path: path, isDependency: true});
+
+            resource.addDependency(new ResourceReference(spritesheet.name, ResourceType.IMAGE));
+            this.resourcesToUnload.push(resource);
 
             // Finish loading
             this.finishLoadingSpritesheet(callbackIfLast);
@@ -460,7 +558,7 @@ export default class ResourceManager {
 
         while(this.loadonly_imageLoadingQueue.hasItems()){
             let image = this.loadonly_imageLoadingQueue.dequeue();
-            this.loadImage(image.key, image.path, onFinishLoading);
+            this.loadImage(image.key, image.path, image.isDependency, onFinishLoading);
         }
     }
 
@@ -470,13 +568,18 @@ export default class ResourceManager {
      * @param path The path to the image to load
      * @param callbackIfLast The function to call if this is the last image
      */
-    public loadImage(key: string, path: string, callbackIfLast: Function): void {
+    public loadImage(key: string, path: string, isDependency: boolean, callbackIfLast: Function): void {
         var image = new Image();
 
         image.onload = () => {
             // Add to loaded images
             this.images.add(key, image);
 
+            // If not a dependency, push it to the unload list. Otherwise it's managed by something else
+            if(!isDependency){
+                this.resourcesToUnload.push(new ResourceReference(key, ResourceType.IMAGE));
+            }
+
             // If WebGL is active, create a texture
             if(this.gl_WebGLActive){
                 this.createWebGLTexture(key, image);
@@ -539,6 +642,7 @@ export default class ResourceManager {
             audioCtx.decodeAudioData(request.response, (buffer) => {
                 // Add to list of audio buffers
                 this.audioBuffers.add(key, buffer);
+                this.resourcesToUnload.push(new ResourceReference(key, ResourceType.AUDIO));
 
                 // Finish loading sound
                 this.finishLoadingAudio(callbackIfLast);
@@ -592,6 +696,9 @@ export default class ResourceManager {
         this.loadTextFile(path, (fileText: string) => {
             let obj = JSON.parse(fileText);
             this.jsonObjects.add(key, obj);
+
+            this.resourcesToUnload.push(new ResourceReference(key, ResourceType.JSON));
+
             this.finishLoadingObject(callbackIfLast);
         });
     }
@@ -706,6 +813,14 @@ export default class ResourceManager {
         this.loadonly_gl_ShaderLoadingQueue.enqueue(paths);
     }
 
+    /**
+     * Tells the resource manager to keep this resource
+     * @param key The key of the resource
+     */
+     public keepShader(key: string): void {
+        this.keepResource(key, ResourceType.IMAGE);
+    }
+
     private gl_LoadShadersFromQueue(onFinishLoading: Function): void {
         this.loadonly_gl_ShaderProgramsToLoad = this.loadonly_gl_ShaderLoadingQueue.getSize();
         this.loadonly_gl_ShaderProgramsLoaded = 0;
@@ -741,6 +856,8 @@ export default class ResourceManager {
                 // Add to our map
                 this.gl_ShaderPrograms.add(key, programWrapper);
 
+                this.resourcesToUnload.push(new ResourceReference(key, ResourceType.SHADER));
+
                 // Finish loading
                 this.gl_FinishLoadingShader(callbackIfLast);
             });
@@ -769,7 +886,7 @@ export default class ResourceManager {
         const program = this.gl.createProgram();
         if(!program) {
             // Error creating
-            console.log("Failed to create program");
+            console.warn("Failed to create program");
             return null;
         }
     
@@ -782,7 +899,7 @@ export default class ResourceManager {
         if(!this.gl.getProgramParameter(program, this.gl.LINK_STATUS)){
             // Error linking
             const error = this.gl.getProgramInfoLog(program);
-            console.log("Failed to link program: " + error);
+            console.warn("Failed to link program: " + error);
     
             // Clean up
             this.gl.deleteProgram(program);
@@ -810,7 +927,7 @@ export default class ResourceManager {
     
         // If we couldn't create the shader, error
         if(shader === null){
-            console.log("Unable to create shader");
+            console.warn("Unable to create shader");
             return null;
         }
     
@@ -822,7 +939,7 @@ export default class ResourceManager {
         if(!this.gl.getShaderParameter(shader, this.gl.COMPILE_STATUS)){
             // Not compiled - error
             const error = this.gl.getShaderInfoLog(shader);
-            console.log("Failed to compile shader: " + error);
+            console.warn("Failed to compile shader: " + error);
     
             // Clean up
             this.gl.deleteShader(shader);
@@ -871,9 +988,44 @@ export default class ResourceManager {
     }
 }
 
+/**
+ * A class representing a reference to a resource.
+ * This is used for the exemption list to assure assets and their dependencies don't get
+ * destroyed if they are still needed.
+ */
+class ResourceReference {
+    key: string;
+    resourceType: ResourceType;
+    dependencies: Array<ResourceReference>;
+
+    constructor(key: string, resourceType: ResourceType){
+        this.key = key;
+        this.resourceType = resourceType;
+        this. dependencies = new Array();
+    }
+
+    addDependency(resource: ResourceReference): void {
+        this.dependencies.push(resource);
+    }
+}
+
+
+enum ResourceType {
+    IMAGE = "IMAGE",
+    TILEMAP = "TILEMAP",
+    SPRITESHEET = "SPRITESHEET",
+    AUDIO = "AUDIO",
+    JSON = "JSON",
+    SHADER = "SHADER"
+}
+
+/**
+ * A pair representing a key and the path of the resource to load
+ */
 class KeyPathPair {
     key: string;
     path: string;
+    isDependency?: boolean = false;
 }
 
 class KeyPath_Shader {

src/Wolfie2D/Scene/Factories/TilemapFactory.ts

@@ -90,7 +90,6 @@ export default class TilemapFactory {
             }
 
             if(isParallaxLayer){
-                console.log("Adding parallax layer: " + layer.name)
                 sceneLayer = this.scene.addParallaxLayer(layer.name, new Vec2(1, 1), depth);
             } else {
                 sceneLayer = this.scene.addLayer(layer.name, depth);

src/Wolfie2D/Scene/Scene.ts

@@ -81,9 +81,12 @@ export default class Scene implements Updateable {
     /** An interface that allows the adding of different nodes to the scene */
     public add: FactoryManager;
 
-    /** An interface that allows the loading of different files for use in the scene */
+    /** An interface that allows the loading of different files for use in the scene. An alias for resourceManager */
     public load: ResourceManager;
 
+    /** An interface that allows the loading and unloading of different files for use in the scene */
+    public resourceManager: ResourceManager;
+
     /** The configuration options for this scene */
     public sceneOptions: SceneOptions;
 
@@ -120,7 +123,8 @@ export default class Scene implements Updateable {
 
         this.add = new FactoryManager(this, this.tilemaps);
 
-        this.load = ResourceManager.getInstance();
+        this.load = ResourceManager.getInstance()
+        this.resourceManager = this.load;
 
         // Get the timer manager and clear any existing timers
         TimerManager.getInstance().clearTimers();
@@ -132,9 +136,6 @@ export default class Scene implements Updateable {
     /** A lifecycle method that gets called when a new scene is created. Load all files you wish to access in the scene here. */
     loadScene(): void {}
 
-    /** A lifecycle method that gets called on scene destruction. Specify which files you no longer need for garbage collection. */
-    unloadScene(): void {}
-
     /** A lifecycle method called strictly after loadScene(). Create any game objects you wish to use in the scene here. */
     startScene(): void {}
 
@@ -144,6 +145,9 @@ export default class Scene implements Updateable {
      */
     updateScene(deltaT: number): void {}
 
+    /** A lifecycle method that gets called on scene destruction. Specify which files you no longer need for garbage collection. */
+    unloadScene(): void {}
+
     update(deltaT: number): void {
         this.updateScene(deltaT);
 
@@ -232,6 +236,12 @@ export default class Scene implements Updateable {
             node.destroy();
         }
 
+        for(let tilemap of this.tilemaps){
+            tilemap.destroy();
+        }
+
+        this.receiver.destroy();
+
         delete this.sceneGraph;
         delete this.physicsManager;
         delete this.navManager;

src/Wolfie2D/Scene/SceneManager.ts

@@ -2,6 +2,7 @@ import Scene from "./Scene";
 import ResourceManager from "../ResourceManager/ResourceManager";
 import Viewport from "../SceneGraph/Viewport";
 import RenderingManager from "../Rendering/RenderingManager";
+import MemoryUtils from "../Utils/MemoryUtils";
 
 /**
  * The SceneManager acts as an interface to create Scenes, and handles the lifecycle methods of Scenes.
@@ -25,6 +26,7 @@ export default class SceneManager {
 
 	/** For consistency, only change scenes at the beginning of the update cycle */
 	protected pendingScene: Scene;
+	protected pendingSceneInit: Record<string, any>;
 
 	/**
 	 * Creates a new SceneManager
@@ -37,6 +39,7 @@ export default class SceneManager {
 		this.viewport = viewport;
 		this.renderingManager = renderingManager;
 		this.idCounter = 0;
+		this.pendingScene = null;
 	}
 
 	/**
@@ -46,31 +49,47 @@ export default class SceneManager {
 	 * @param init An object to pass to the init function of the new scene
 	 */
 	public changeToScene<T extends Scene>(constr: new (...args: any) => T, init?: Record<string, any>, options?: Record<string, any>): void {
+		console.log("Creating the new scene - change is pending until next update");
+		this.pendingScene = new constr(this.viewport, this, this.renderingManager, options);
+		this.pendingSceneInit = init;
+	}
+
+	protected doSceneChange(){
+		console.log("Performing scene change");
 		this.viewport.setCenter(this.viewport.getHalfSize().x, this.viewport.getHalfSize().y);
 		
-		let scene = new constr(this.viewport, this, this.renderingManager, options);
-		
 		if(this.currentScene){
-			console.log("Destroying Old Scene");
+			console.log("Unloading old scene")
+			this.currentScene.unloadScene();
+
+			console.log("Destroying old scene");
 			this.currentScene.destroy();
 		}
 
-		this.currentScene = scene;
+		console.log("Unloading old resources...");
+		this.resourceManager.unloadAllResources();
 
-		scene.initScene(init);
+		// Make the pending scene the current one
+		this.currentScene = this.pendingScene;
+
+		// Make the pending scene null
+		this.pendingScene = null;
+
+		// Init the scene
+		this.currentScene.initScene(this.pendingSceneInit);
 
 		// Enqueue all scene asset loads
-		scene.loadScene();
+		this.currentScene.loadScene();
 
 		// Load all assets
 		console.log("Starting Scene Load");
 		this.resourceManager.loadResourcesFromQueue(() => {
 			console.log("Starting Scene");
-			scene.startScene();
+			this.currentScene.startScene();
-			scene.setRunning(true);
+			this.currentScene.setRunning(true);
 		});
 
-		this.renderingManager.setScene(scene);
+		this.renderingManager.setScene(this.currentScene);
 	}
 	
 	/**
@@ -85,7 +104,9 @@ export default class SceneManager {
 	 * Renders the current Scene
 	 */
 	public render(): void {
-		this.currentScene.render();
+		if(this.currentScene){
+			this.currentScene.render();
+		}
 	}
 
 	/**
@@ -93,7 +114,11 @@ export default class SceneManager {
 	 * @param deltaT The timestep of the Scene
 	 */
 	public update(deltaT: number){
-		if(this.currentScene.isRunning()){
+		if(this.pendingScene !== null){
+			this.doSceneChange();
+		}
+
+		if(this.currentScene && this.currentScene.isRunning()){
 			this.currentScene.update(deltaT);
 		}
 	}

src/Wolfie2D/SceneGraph/Viewport.ts

@@ -155,7 +155,7 @@ export default class Viewport {
      * @param zoom The zoom level
      */
     setZoomLevel(zoom: number): void {
-        this.view.halfSize.scale(1/zoom);
+        this.view.halfSize.copy(this.canvasSize.scaled(1/zoom/2));
     }
 
     /**

src/Wolfie2D/Sound/AudioManager.ts

@@ -46,7 +46,7 @@ export default class AudioManager {
             this.audioCtx = new AudioContext(); 
             console.log('Web Audio API successfully loaded');
         } catch(e) {
-            console.log('Web Audio API is not supported in this browser'); 
+            console.warn('Web Audio API is not supported in this browser'); 
         }
     }
 

src/Wolfie2D/Utils/MemoryUtils.ts

@@ -0,0 +1,46 @@
+import Stack from "../DataTypes/Stack";
+
+export default class MemoryUtils {
+    /**
+     * Returns an approximate size in bytes of any object
+     * @param obj The object to get the size of
+     * @returns An approximation of the number of bytes in the object provided
+     */
+    static approxSizeOf(obj: any): number {
+        let objectList = new Array<object>();
+        let stack = new Stack<any>(10000);
+        stack.push(obj);
+        let bytes = 0;
+
+        while(!stack.isEmpty()){
+            let item = stack.pop();
+
+            // We aren't interested in counting window and document
+            if(item === window || item === document) continue;
+
+            if((typeof item) === "boolean"){
+                bytes += 4;
+            } else if((typeof item) === "number"){
+                bytes += 8;
+            } else if((typeof item) === "string"){
+                bytes += item.length;
+            } else if((typeof item) === "object" && objectList.indexOf(item) === -1){
+                // We haven't seen this object before - log it
+                objectList.push(item);
+
+                // Get the number of bytes in all of its fields
+                for(let field in item){
+                    try {
+                        stack.push(item[field]);
+                    } catch(e){
+                        console.log("Pushing item: ", + item[field]);
+                        console.warn(`Ran out of room counting memory (Stack has size ${stack.size()}) - returning current number of bytes`);
+                        return bytes;
+                    }
+                }
+            }
+        }
+
+        return bytes;
+    }
+}