fixed fps tracking in game loop

src/BoidDemo.ts

@@ -32,7 +32,7 @@ export default class BoidDemo extends Scene {
         this.viewport.enableZoom();
 
         // Create a bunch of boids
-        for(let i = 0; i < 100; i++){
+        for(let i = 0; i < 200; i++){
             let boid = this.add.graphic(Boid, layer, new Vec2(this.worldSize.x*Math.random(), this.worldSize.y*Math.random()));
             boid.fb = new FlockBehavior(this, boid, this.boids, 75, 50);
             boid.setSize(5, 5);

src/DataTypes/RegionQuadTree.ts

@@ -45,12 +45,25 @@ export default class QuadTree<T extends Region & Unique> implements Collection {
         this.capacity = capacity ? capacity : 10;
         
         // If we're at the bottom of the tree, don't set a max size
-        if(this.maxDepth === 0){
+        if(this.maxDepth === 1){
             this.capacity = Infinity;
         }
 
         this.divided = false;
         this.items = new Array();
+
+        // Create all of the children for this quadtree if there are any
+        if(this.maxDepth > 1){
+            let x = this.boundary.x;
+            let y = this.boundary.y;
+            let hw = this.boundary.hw;
+            let hh = this.boundary.hh;
+
+            this.nw = new QuadTree(new Vec2(x-hw/2, y-hh/2), new Vec2(hw/2, hh/2), this.maxDepth - 1, this.capacity);
+            this.ne = new QuadTree(new Vec2(x+hw/2, y-hh/2), new Vec2(hw/2, hh/2), this.maxDepth - 1, this.capacity);
+            this.sw = new QuadTree(new Vec2(x-hw/2, y+hh/2), new Vec2(hw/2, hh/2), this.maxDepth - 1, this.capacity);
+            this.se = new QuadTree(new Vec2(x+hw/2, y+hh/2), new Vec2(hw/2, hh/2), this.maxDepth - 1, this.capacity);
+        }
     }
 
     /**
@@ -71,7 +84,6 @@ export default class QuadTree<T extends Region & Unique> implements Collection {
                 // We aren't divided, but are at capacity - divide
                 this.subdivide();
                 this.deferInsert(item);
-                this.divided = true;
             }
         }
     }
@@ -173,16 +185,7 @@ export default class QuadTree<T extends Region & Unique> implements Collection {
      * Divides this quadtree up into 4 smaller ones - called through insert.
      */
     protected subdivide(): void {
-        let x = this.boundary.x;
+        this.divided = true;
-        let y = this.boundary.y;
-        let hw = this.boundary.hw;
-        let hh = this.boundary.hh;
-
-        this.nw = new QuadTree(new Vec2(x-hw/2, y-hh/2), new Vec2(hw/2, hh/2), this.maxDepth - 1, this.capacity);
-        this.ne = new QuadTree(new Vec2(x+hw/2, y-hh/2), new Vec2(hw/2, hh/2), this.maxDepth - 1, this.capacity);
-        this.sw = new QuadTree(new Vec2(x-hw/2, y+hh/2), new Vec2(hw/2, hh/2), this.maxDepth - 1, this.capacity);
-        this.se = new QuadTree(new Vec2(x+hw/2, y+hh/2), new Vec2(hw/2, hh/2), this.maxDepth - 1, this.capacity);
-
         this.distributeItems();
     }
 
@@ -239,11 +242,16 @@ export default class QuadTree<T extends Region & Unique> implements Collection {
         }
     }
 
+    /**
+     * Clear the items in this quadtree
+     */
     clear(): void {
-        delete this.nw;
+        if(this.nw){
-        delete this.ne;
+            this.nw.clear();
-        delete this.sw;
+            this.ne.clear();
-        delete this.se;
+            this.sw.clear();
+            this.se.clear();
+        }
 
         for(let item in this.items){
             delete this.items[item];

src/Loop/GameLoop.ts

@@ -9,26 +9,46 @@ import SceneManager from "../Scene/SceneManager";
 import AudioManager from "../Sound/AudioManager";
 
 export default class GameLoop {
-	// The amount of time to spend on a physics step
+	/** The max allowed update fps.*/
-	private maxFPS: number;
+    private maxUpdateFPS: number;
+    
+    /** The timestep for each update. This is the deltaT passed to update calls. */
 	private simulationTimestep: number;
 
-	// The time when the last frame was drawn
+    /** The amount of time we are yet to simulate. */
-	private lastFrameTime: number;
+    private frameDelta: number;
 
-	// The current frame of the game
+    /** The time when the last frame was drawn. */
+    private lastFrameTime: number;
+    
+    /** The minimum time we want to wait between game frames. */
+    private minFrameDelay: number;
+
+	/** The current frame of the game. */
 	private frame: number;
 
-	// Keeping track of the fps
+	/** The actual fps of the game. */
-	private runningFrameSum: number;
+    private fps: number;
-	private numFramesInSum: number;
-	private maxFramesInSum: number;
-	private fps: number;
     
-	private started: boolean;
+    /** The time between fps measurement updates. */
-	private running: boolean;
+    private fpsUpdateInterval: number;
-    private frameDelta: number;
+
+    /** The time of the last fps update. */
+    private lastFpsUpdate: number;
+
+    /** The number of frames since the last fps update was done. */
+    private framesSinceLastFpsUpdate: number;
+
+    /** The status of whether or not the game loop has started. */
+    private started: boolean;
+    
+    /** The status of whether or not the game loop is currently running. */
+    private running: boolean;
+    
+    /** The panic state of the game. True if we have too many update frames in a single render. */
     private panic: boolean;
+
+    /** The number of update steps this iteration of the game loop. */
     private numUpdateSteps: number;
 
     // Game canvas and its width and height
@@ -51,16 +71,23 @@ export default class GameLoop {
         // Typecast the config object to a GameConfig object
         let gameConfig = config ? <GameConfig>config : new GameConfig();
 
-        this.maxFPS = 60;
+        this.maxUpdateFPS = 60;
-        this.simulationTimestep = Math.floor(1000/this.maxFPS);
+        this.simulationTimestep = Math.floor(1000/this.maxUpdateFPS);
+        this.frameDelta = 0;
+        this.lastFrameTime = 0;
+        this.minFrameDelay = 0;
         this.frame = 0;
-        this.runningFrameSum = 0;
+        this.fps = this.maxUpdateFPS;   // Initialize the fps to the max allowed fps
-        this.numFramesInSum = 0;
+        this.fpsUpdateInterval = 1000;
-        this.maxFramesInSum = 30;
+        this.lastFpsUpdate = 0;
-        this.fps = this.maxFPS;
+        this.framesSinceLastFpsUpdate = 0;
-
         this.started = false;
         this.running = false;
+        this.panic = false;
+        this.numUpdateSteps = 0;
+
+        // Set the max fps to 60fps
+        // this.setMaxFPS(60);
 
         // Get the game canvas and give it a background color
         this.GAME_CANVAS = <HTMLCanvasElement>document.getElementById("game-canvas");
@@ -103,9 +130,13 @@ export default class GameLoop {
      * Changes the maximum allowed physics framerate of the game
      * @param initMax 
      */
-    setMaxFPS(initMax: number): void {
+    setMaxUpdateFPS(initMax: number): void {
-        this.maxFPS = initMax;
+        this.maxUpdateFPS = initMax;
-        this.simulationTimestep = Math.floor(1000/this.maxFPS);
+        this.simulationTimestep = Math.floor(1000/this.maxUpdateFPS);
+    }
+
+    setMaxFPS(maxFPS: number): void {
+        this.minFrameDelay = 1000/maxFPS;
     }
 
     getSceneManager(): SceneManager {
@@ -116,15 +147,10 @@ export default class GameLoop {
      * Updates the frame count and sum of time for the framerate of the game
      * @param timestep 
      */
-    private updateFrameCount(timestep: number): void {
+    private updateFPS(timestamp: number): void {
-        this.frame += 1;
+        this.fps = 0.9 * this.framesSinceLastFpsUpdate * 1000 / (timestamp - this.lastFpsUpdate) +(1 - 0.9) * this.fps;
-        this.numFramesInSum += 1;
+        this.lastFpsUpdate = timestamp;
-        this.runningFrameSum += timestep;
+        this.framesSinceLastFpsUpdate = 0;
-        if(this.numFramesInSum >= this.maxFramesInSum){
-            this.fps = 1000 * this.numFramesInSum / this.runningFrameSum;
-            this.numFramesInSum = 0;
-            this.runningFrameSum = 0;
-        }
 
         Debug.log("fps", "FPS: " + this.fps.toFixed(1));
     }
@@ -150,6 +176,8 @@ export default class GameLoop {
         this.render();
 
         this.lastFrameTime = timestamp;
+        this.lastFpsUpdate = timestamp;
+        this.framesSinceLastFpsUpdate = 0;
 
         window.requestAnimationFrame(this.doFrame);
     }
@@ -163,14 +191,22 @@ export default class GameLoop {
         window.requestAnimationFrame(this.doFrame);
 
         // If we are trying to update too soon, return and do nothing
-        if(timestamp < this.lastFrameTime + this.simulationTimestep){
+        if(timestamp < this.lastFrameTime + this.minFrameDelay){
             return
         }
 
         // Currently, update and draw are synced - eventually it would probably be good to desync these
-        this.frameDelta = timestamp - this.lastFrameTime;
+        this.frameDelta += timestamp - this.lastFrameTime;
         this.lastFrameTime = timestamp;
 
+        // Update the estimate of the framerate
+        if(timestamp > this.lastFpsUpdate + this.fpsUpdateInterval){
+            this.updateFPS(timestamp);
+        }
+
+        this.frame++;
+        this.framesSinceLastFpsUpdate++;
+
         // Update while we can (This will present problems if we leave the window)
         this.numUpdateSteps = 0;
         while(this.frameDelta >= this.simulationTimestep){
@@ -181,9 +217,6 @@ export default class GameLoop {
             if(this.numUpdateSteps > 100){
                 this.panic = true;
             }
-
-            // Update the frame of the game
-            this.updateFrameCount(this.simulationTimestep);
         }
 
         // Updates are done, draw

src/MainScene.ts

@@ -95,7 +95,7 @@ export default class MainScene extends Scene {
         let i = 0;
         let fps = [15, 30, 60];
         cycleFramerateButton.onClick = () => {
-            this.game.setMaxFPS(fps[i]);
+            this.game.setMaxUpdateFPS(fps[i]);
             i = (i + 1) % 3;
         }
 

src/SecondScene.ts

@@ -72,7 +72,7 @@ export default class SecondScene extends Scene {
         let i = 0;
         let fps = [15, 30, 60];
         cycleFramerateButton.onClick = () => {
-            this.game.setMaxFPS(fps[i]);
+            this.game.setMaxUpdateFPS(fps[i]);
             i = (i + 1) % 3;
         }