From c6e9baa0009f7cce0f6ff156a3957ef04a8cb684 Mon Sep 17 00:00:00 2001
From: Elizabeth Hunt <elizabeth.hunt@simponic.xyz>
Date: Sat, 12 Aug 2023 13:49:16 -0600
Subject: [PATCH] the great engine refactor

---
 client/src/JumpStorm.ts                      |   7 +-
 client/src/components/GameCanvas.svelte      |   2 +-
 client/src/components/LeaderBoard.svelte     |   3 +-
 client/src/components/LeaderBoardCard.svelte |   4 +-
 engine/Game.ts                               |  25 +++-
 engine/components/BoundingBox.ts             |  57 ++++-----
 engine/components/Control.ts                 |   8 +-
 engine/components/Forces.ts                  |   2 +-
 engine/components/Sprite.ts                  |   6 +-
 engine/components/Velocity.ts                |  10 +-
 engine/config/assets.ts                      |  10 +-
 engine/config/constants.ts                   |   8 +-
 engine/config/sprites.ts                     |  35 +++---
 engine/entities/Entity.ts                    |   1 -
 engine/entities/Floor.ts                     |  14 ++-
 engine/entities/Player.ts                    |  15 +--
 engine/interfaces/LeaderBoardEntry.ts        |   5 -
 engine/interfaces/index.ts                   |   1 -
 engine/structures/QuadTree.ts                |  91 +++++++++-----
 engine/systems/Collision.ts                  | 126 +++++++++----------
 engine/systems/FacingDirection.ts            |  25 ++--
 engine/systems/Input.ts                      |  82 ++++++------
 engine/systems/Physics.ts                    |  34 +++--
 engine/systems/Render.ts                     |  55 ++++----
 engine/systems/System.ts                     |   1 -
 engine/systems/WallBounds.ts                 |  27 ++--
 engine/utils/index.ts                        |   1 -
 engine/utils/normalizeVector.ts              |   8 --
 server/src/server.ts                         |  16 +--
 29 files changed, 345 insertions(+), 334 deletions(-)
 delete mode 100644 engine/interfaces/LeaderBoardEntry.ts
 delete mode 100644 engine/utils/normalizeVector.ts

diff --git a/client/src/JumpStorm.ts b/client/src/JumpStorm.ts
index d1d1013..bd48483 100644
--- a/client/src/JumpStorm.ts
+++ b/client/src/JumpStorm.ts
@@ -17,11 +17,6 @@ export class JumpStorm {
     this.game = new Game();
     this.socket = new WebSocket("ws://localhost:8080");
 
-    this.socket.onopen = () => {
-      this.socket.send("gaming");
-      console.log("OPENED SOCKET");
-    };
-
     [
       this.createInputSystem(),
       new FacingDirection(),
@@ -32,7 +27,7 @@ export class JumpStorm {
     ].forEach((system) => this.game.addSystem(system));
 
     [new Floor(160), new Player()].forEach((entity) =>
-      this.game.addEntity(entity)
+      this.game.addEntity(entity),
     );
   }
 
diff --git a/client/src/components/GameCanvas.svelte b/client/src/components/GameCanvas.svelte
index d7abecf..ae8c1b0 100644
--- a/client/src/components/GameCanvas.svelte
+++ b/client/src/components/GameCanvas.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
   import { onMount } from "svelte";
   import { loadAssets } from "@engine/config";
-  import { JumpStorm} from "../Jumpstorm";
+  import { JumpStorm } from "../JumpStorm";
   
   let canvas: HTMLCanvasElement;
   let ctx: CanvasRenderingContext2D;
diff --git a/client/src/components/LeaderBoard.svelte b/client/src/components/LeaderBoard.svelte
index 880e64a..8343c56 100644
--- a/client/src/components/LeaderBoard.svelte
+++ b/client/src/components/LeaderBoard.svelte
@@ -1,10 +1,9 @@
 <script lang="ts">
-  import { type LeaderBoardEntry } from "@engine/interfaces";
   import LeaderBoardCard from "./LeaderBoardCard.svelte";
 
   const MAX_ENTRIES = 8;
 
-  export let entries: LeaderBoardEntry[] = [];
+  export let entries: { name: string, score: number }[] = [];
 </script>
 
 <div class="leaderboard">
diff --git a/client/src/components/LeaderBoardCard.svelte b/client/src/components/LeaderBoardCard.svelte
index f46c000..ae30e1a 100644
--- a/client/src/components/LeaderBoardCard.svelte
+++ b/client/src/components/LeaderBoardCard.svelte
@@ -1,7 +1,5 @@
 <script lang="ts">
-  import { type LeaderBoardEntry } from "@engine/interfaces";
-
-  export let entry: LeaderBoardEntry = {
+  export let entry = {
     name: "simponic",
     score: 100,
   };
diff --git a/engine/Game.ts b/engine/Game.ts
index 3682fbd..07d06e8 100644
--- a/engine/Game.ts
+++ b/engine/Game.ts
@@ -12,6 +12,7 @@ export class Game {
   public componentEntities: Map<string, Set<number>>;
 
   constructor() {
+    this.lastTimeStamp = performance.now();
     this.running = false;
     this.systemOrder = [];
     this.systems = new Map();
@@ -28,7 +29,7 @@ export class Game {
     this.entities.set(entity.id, entity);
   }
 
-  public getEntity(id: number): Entity {
+  public getEntity(id: number): Entity | undefined {
     return this.entities.get(id);
   }
 
@@ -36,6 +37,18 @@ export class Game {
     this.entities.delete(id);
   }
 
+  public forEachEntityWithComponent(
+    componentName: string,
+    callback: (entity: Entity) => void,
+  ) {
+    this.componentEntities.get(componentName)?.forEach((entityId) => {
+      const entity = this.getEntity(entityId);
+      if (!entity) return;
+
+      callback(entity);
+    });
+  }
+
   public addSystem(system: System) {
     if (!this.systemOrder.includes(system.name)) {
       this.systemOrder.push(system.name);
@@ -43,7 +56,7 @@ export class Game {
     this.systems.set(system.name, system);
   }
 
-  public getSystem(name: string): System {
+  public getSystem(name: string): System | undefined {
     return this.systems.get(name);
   }
 
@@ -62,16 +75,16 @@ export class Game {
         if (!this.componentEntities.has(component.name)) {
           this.componentEntities.set(
             component.name,
-            new Set<number>([entity.id])
+            new Set<number>([entity.id]),
           );
           return;
         }
-        this.componentEntities.get(component.name).add(entity.id);
-      })
+        this.componentEntities.get(component.name)?.add(entity.id);
+      }),
     );
 
     this.systemOrder.forEach((systemName) => {
-      this.systems.get(systemName).update(dt, this);
+      this.systems.get(systemName)?.update(dt, this);
     });
   };
 }
diff --git a/engine/components/BoundingBox.ts b/engine/components/BoundingBox.ts
index 2b1d648..5e21b2f 100644
--- a/engine/components/BoundingBox.ts
+++ b/engine/components/BoundingBox.ts
@@ -1,6 +1,6 @@
 import { Component, ComponentNames } from ".";
 import type { Coord2D, Dimension2D } from "../interfaces";
-import { dotProduct, rotateVector, normalizeVector } from "../utils";
+import { dotProduct, rotateVector } from "../utils";
 
 export class BoundingBox extends Component {
   public center: Coord2D;
@@ -15,10 +15,11 @@ export class BoundingBox extends Component {
     this.rotation = rotation ?? 0;
   }
 
+  // https://en.wikipedia.org/wiki/Hyperplane_separation_theorem
   public isCollidingWith(box: BoundingBox): boolean {
     const boxes = [this.getVertices(), box.getVertices()];
     for (const poly of boxes) {
-      for (let i = 0; i < poly.length; ++i) {
+      for (let i = 0; i < poly.length; i++) {
         const [A, B] = [poly[i], poly[(i + 1) % poly.length]];
         const normal: Coord2D = { x: B.y - A.y, y: A.x - B.x };
 
@@ -28,8 +29,8 @@ export class BoundingBox extends Component {
               const projection = dotProduct(normal, vertex);
               return [Math.min(min, projection), Math.max(max, projection)];
             },
-            [Infinity, -Infinity]
-          )
+            [Infinity, -Infinity],
+          ),
         );
 
         if (maxThis < minBox || maxBox < minThis) return false;
@@ -55,43 +56,29 @@ export class BoundingBox extends Component {
       });
   }
 
-  private getAxes() {
-    const corners: Coord2D[] = this.getVerticesRelativeToCenter();
-    const axes: Coord2D[] = [];
-
-    for (let i = 0; i < corners.length; ++i) {
-      const [cornerA, cornerB] = [
-        corners[i],
-        corners[(i + 1) % corners.length],
-      ].map((corner) => rotateVector(corner, this.rotation));
-
-      axes.push(
-        normalizeVector({
-          x: cornerB.y - cornerA.y,
-          y: -(cornerB.x - cornerA.x),
-        })
-      );
+  public getRotationInPiOfUnitCircle() {
+    let rads = this.rotation * (Math.PI / 180);
+    if (rads >= Math.PI) {
+      rads -= Math.PI;
     }
-
-    return axes;
+    return rads;
   }
 
-  private project(axis: Coord2D): [number, number] {
-    const corners = this.getCornersRelativeToCenter();
-    let [min, max] = [Infinity, -Infinity];
+  public getOutscribedBoxDims(): Dimension2D {
+    let rads = this.getRotationInPiOfUnitCircle();
+    const { width, height } = this.dimension;
 
-    for (const corner of corners) {
-      const rotated = rotateVector(corner, this.rotation);
-      const translated = {
-        x: rotated.x + this.center.x,
-        y: rotated.y + this.center.y,
+    if (rads <= Math.PI / 2) {
+      return {
+        width: Math.abs(height * Math.sin(rads) + width * Math.cos(rads)),
+        height: Math.abs(width * Math.sin(rads) + height * Math.cos(rads)),
       };
-      const projection = dotProduct(translated, axis);
-
-      min = Math.min(projection, min);
-      max = Math.max(projection, max);
     }
 
-    return [min, max];
+    rads -= Math.PI / 2;
+    return {
+      width: Math.abs(height * Math.cos(rads) + width * Math.sin(rads)),
+      height: Math.abs(width * Math.cos(rads) + height * Math.sin(rads)),
+    };
   }
 }
diff --git a/engine/components/Control.ts b/engine/components/Control.ts
index 094ef1c..1e782ee 100644
--- a/engine/components/Control.ts
+++ b/engine/components/Control.ts
@@ -1,7 +1,11 @@
-import { Component, ComponentNames } from ".";
+import { Component, ComponentNames, Velocity } from ".";
 
 export class Control extends Component {
-  constructor() {
+  public controlVelocity: Velocity;
+
+  constructor(controlVelocity: Velocity = new Velocity()) {
     super(ComponentNames.Control);
+
+    this.controlVelocity = controlVelocity;
   }
 }
diff --git a/engine/components/Forces.ts b/engine/components/Forces.ts
index bf540a1..91ae1c1 100644
--- a/engine/components/Forces.ts
+++ b/engine/components/Forces.ts
@@ -1,4 +1,4 @@
-import type { Accel2D, Force2D } from "../interfaces";
+import type { Force2D } from "../interfaces";
 import { Component } from "./Component";
 import { ComponentNames } from ".";
 
diff --git a/engine/components/Sprite.ts b/engine/components/Sprite.ts
index 90e1389..bdb4982 100644
--- a/engine/components/Sprite.ts
+++ b/engine/components/Sprite.ts
@@ -17,7 +17,7 @@ export class Sprite extends Component {
     spriteImgPos: Coord2D,
     spriteImgDimensions: Dimension2D,
     msPerFrame: number,
-    numFrames: number
+    numFrames: number,
   ) {
     super(ComponentNames.Sprite);
 
@@ -44,7 +44,7 @@ export class Sprite extends Component {
 
     ctx.save();
     ctx.translate(center.x, center.y);
-    if (rotation != 0) {
+    if (rotation != undefined && rotation != 0) {
       ctx.rotate(rotation * (Math.PI / 180));
     }
     ctx.translate(-center.x, -center.y);
@@ -56,7 +56,7 @@ export class Sprite extends Component {
     ctx.drawImage(
       this.sheet,
       ...this.getSpriteArgs(),
-      ...this.getDrawArgs(drawArgs)
+      ...this.getDrawArgs(drawArgs),
     );
 
     if (tint) {
diff --git a/engine/components/Velocity.ts b/engine/components/Velocity.ts
index 119427d..068d8cd 100644
--- a/engine/components/Velocity.ts
+++ b/engine/components/Velocity.ts
@@ -6,10 +6,18 @@ export class Velocity extends Component {
   public dCartesian: Velocity2D;
   public dTheta: number;
 
-  constructor(dCartesian: Velocity2D, dTheta: number) {
+  constructor(dCartesian: Velocity2D = { dx: 0, dy: 0 }, dTheta: number = 0) {
     super(ComponentNames.Velocity);
 
     this.dCartesian = dCartesian;
     this.dTheta = dTheta;
   }
+
+  public add(velocity?: Velocity) {
+    if (velocity) {
+      this.dCartesian.dx += velocity.dCartesian.dx;
+      this.dCartesian.dy += velocity.dCartesian.dy;
+      this.dTheta += velocity.dTheta;
+    }
+  }
 }
diff --git a/engine/config/assets.ts b/engine/config/assets.ts
index 51a5303..173bab3 100644
--- a/engine/config/assets.ts
+++ b/engine/config/assets.ts
@@ -4,7 +4,7 @@ import { SPRITE_SPECS } from "./sprites";
 export const IMAGES = new Map<string, HTMLImageElement>();
 
 export const loadSpritesIntoImageElements = (
-  spriteSpecs: Partial<SpriteSpec>[]
+  spriteSpecs: Partial<SpriteSpec>[],
 ): Promise<void>[] => {
   const spritePromises: Promise<void>[] = [];
 
@@ -17,13 +17,13 @@ export const loadSpritesIntoImageElements = (
       spritePromises.push(
         new Promise((resolve) => {
           img.onload = () => resolve();
-        })
+        }),
       );
     }
 
     if (spriteSpec.states) {
       spritePromises.push(
-        ...loadSpritesIntoImageElements(Object.values(spriteSpec.states))
+        ...loadSpritesIntoImageElements(Array.from(spriteSpec.states.values())),
       );
     }
   }
@@ -34,7 +34,9 @@ export const loadSpritesIntoImageElements = (
 export const loadAssets = () =>
   Promise.all([
     ...loadSpritesIntoImageElements(
-      Array.from(SPRITE_SPECS.keys()).map((key) => SPRITE_SPECS.get(key))
+      Array.from(SPRITE_SPECS.keys()).map(
+        (key) => SPRITE_SPECS.get(key) as SpriteSpec,
+      ),
     ),
     // TODO: Sound
   ]);
diff --git a/engine/config/constants.ts b/engine/config/constants.ts
index 9a3169b..3d536d3 100644
--- a/engine/config/constants.ts
+++ b/engine/config/constants.ts
@@ -11,12 +11,12 @@ export namespace KeyConstants {
   };
 
   export const ActionKeys: Map<Action, string[]> = Object.keys(
-    KeyActions
+    KeyActions,
   ).reduce((acc: Map<Action, string[]>, key) => {
     const action = KeyActions[key];
 
     if (acc.has(action)) {
-      acc.get(action).push(key);
+      acc.get(action)?.push(key);
       return acc;
     }
 
@@ -29,8 +29,8 @@ export namespace PhysicsConstants {
   export const MAX_JUMP_TIME_MS = 150;
   export const GRAVITY = 0.0075;
   export const PLAYER_MOVE_VEL = 1;
-  export const PLAYER_JUMP_ACC = -0.01;
-  export const PLAYER_JUMP_INITIAL_VEL = -0.9;
+  export const PLAYER_JUMP_ACC = -0.008;
+  export const PLAYER_JUMP_INITIAL_VEL = -1;
 }
 
 export namespace Miscellaneous {
diff --git a/engine/config/sprites.ts b/engine/config/sprites.ts
index 18bec73..1f65c18 100644
--- a/engine/config/sprites.ts
+++ b/engine/config/sprites.ts
@@ -10,7 +10,7 @@ export interface SpriteSpec {
   height: number;
   frames: number;
   msPerFrame: number;
-  states?: Record<string | number, Partial<SpriteSpec>>;
+  states?: Map<string | number, Partial<SpriteSpec>>;
 }
 
 export const SPRITE_SPECS: Map<Sprites, Partial<SpriteSpec>> = new Map<
@@ -22,28 +22,27 @@ const floorSpriteSpec = {
   height: 40,
   frames: 3,
   msPerFrame: 125,
-  states: {},
+  states: new Map<number, Partial<SpriteSpec>>(),
 };
-floorSpriteSpec.states = [40, 80, 120, 160].reduce((acc, cur) => {
-  acc[cur] = {
-    width: cur,
-    sheet: `/assets/floor_tile_${cur}.png`,
-  };
-  return acc;
-}, {});
+[40, 80, 120, 160].forEach((width) => {
+  floorSpriteSpec.states.set(width, {
+    width,
+    sheet: `/assets/floor_tile_${width}.png`,
+  });
+});
 SPRITE_SPECS.set(Sprites.FLOOR, floorSpriteSpec);
 
-SPRITE_SPECS.set(Sprites.COFFEE, {
+const coffeeSpriteSpec = {
   msPerFrame: 100,
   width: 60,
   height: 45,
   frames: 3,
-  states: {
-    LEFT: {
-      sheet: "/assets/coffee_left.png",
-    },
-    RIGHT: {
-      sheet: "/assets/coffee_right.png",
-    },
-  },
+  states: new Map<string, Partial<SpriteSpec>>(),
+};
+coffeeSpriteSpec.states.set("LEFT", {
+  sheet: "/assets/coffee_left.png",
 });
+coffeeSpriteSpec.states.set("RIGHT", {
+  sheet: "/assets/coffee_right.png",
+});
+SPRITE_SPECS.set(Sprites.COFFEE, coffeeSpriteSpec);
diff --git a/engine/entities/Entity.ts b/engine/entities/Entity.ts
index e57ccde..ca8d314 100644
--- a/engine/entities/Entity.ts
+++ b/engine/entities/Entity.ts
@@ -1,5 +1,4 @@
 import type { Component } from "../components";
-import { ComponentNotFoundError } from "../exceptions";
 
 export abstract class Entity {
   private static ID = 0;
diff --git a/engine/entities/Floor.ts b/engine/entities/Floor.ts
index d51badc..44587e6 100644
--- a/engine/entities/Floor.ts
+++ b/engine/entities/Floor.ts
@@ -4,26 +4,28 @@ import { TopCollidable } from "../components/TopCollidable";
 import { Entity } from "../entities";
 
 export class Floor extends Entity {
-  private static spriteSpec: SpriteSpec = SPRITE_SPECS.get(Sprites.FLOOR);
+  private static spriteSpec: SpriteSpec = SPRITE_SPECS.get(
+    Sprites.FLOOR,
+  ) as SpriteSpec;
 
   constructor(width: number) {
     super();
 
     this.addComponent(
       new Sprite(
-        IMAGES.get(Floor.spriteSpec.states[width].sheet),
+        IMAGES.get((Floor.spriteSpec?.states?.get(width) as SpriteSpec).sheet),
         { x: 0, y: 0 },
         { width, height: Floor.spriteSpec.height },
         Floor.spriteSpec.msPerFrame,
-        Floor.spriteSpec.frames
-      )
+        Floor.spriteSpec.frames,
+      ),
     );
 
     this.addComponent(
       new BoundingBox(
         { x: 300, y: 300 },
-        { width, height: Floor.spriteSpec.height }
-      )
+        { width, height: Floor.spriteSpec.height },
+      ),
     );
 
     this.addComponent(new TopCollidable());
diff --git a/engine/entities/Player.ts b/engine/entities/Player.ts
index 0ba5a41..45d7500 100644
--- a/engine/entities/Player.ts
+++ b/engine/entities/Player.ts
@@ -14,14 +14,15 @@ import {
   Mass,
   Moment,
 } from "../components";
-import { PhysicsConstants } from "../config";
 import { Direction } from "../interfaces";
 
 export class Player extends Entity {
   private static MASS: number = 10;
   private static MOI: number = 1000;
 
-  private static spriteSpec: SpriteSpec = SPRITE_SPECS.get(Sprites.COFFEE);
+  private static spriteSpec: SpriteSpec = SPRITE_SPECS.get(
+    Sprites.COFFEE,
+  ) as SpriteSpec;
 
   constructor() {
     super();
@@ -30,8 +31,8 @@ export class Player extends Entity {
       new BoundingBox(
         { x: 300, y: 100 },
         { width: Player.spriteSpec.width, height: Player.spriteSpec.height },
-        0
-      )
+        0,
+      ),
     );
 
     this.addComponent(new Velocity({ dx: 0, dy: 0 }, 0));
@@ -54,12 +55,12 @@ export class Player extends Entity {
     const [leftSprite, rightSprite] = [Direction.LEFT, Direction.RIGHT].map(
       (direction) =>
         new Sprite(
-          IMAGES.get(Player.spriteSpec.states[direction].sheet),
+          IMAGES.get(Player.spriteSpec.states?.get(direction)?.sheet as string),
           { x: 0, y: 0 },
           { width: Player.spriteSpec.width, height: Player.spriteSpec.height },
           Player.spriteSpec.msPerFrame,
-          Player.spriteSpec.frames
-        )
+          Player.spriteSpec.frames,
+        ),
     );
 
     this.addComponent(new FacingDirection(leftSprite, rightSprite));
diff --git a/engine/interfaces/LeaderBoardEntry.ts b/engine/interfaces/LeaderBoardEntry.ts
deleted file mode 100644
index 1b1e7b3..0000000
--- a/engine/interfaces/LeaderBoardEntry.ts
+++ /dev/null
@@ -1,5 +0,0 @@
-export interface LeaderBoardEntry {
-  name: string;
-  score: number;
-  avatar: string;
-}
diff --git a/engine/interfaces/index.ts b/engine/interfaces/index.ts
index 0398abd..8cdf4d8 100644
--- a/engine/interfaces/index.ts
+++ b/engine/interfaces/index.ts
@@ -1,4 +1,3 @@
-export * from "./LeaderBoardEntry";
 export * from "./Vec2";
 export * from "./Draw";
 export * from "./Direction";
diff --git a/engine/structures/QuadTree.ts b/engine/structures/QuadTree.ts
index 7913e59..d1ff3b1 100644
--- a/engine/structures/QuadTree.ts
+++ b/engine/structures/QuadTree.ts
@@ -1,6 +1,4 @@
 import type { Coord2D, Dimension2D } from "../interfaces";
-import { ComponentNames, BoundingBox } from "../components";
-import { Entity } from "../entities";
 
 interface BoxedEntry {
   id: number;
@@ -30,21 +28,26 @@ export class QuadTree {
     dimension: Dimension2D,
     maxLevels: number,
     splitThreshold: number,
-    level?: number
+    level?: number,
   ) {
-    this.children = [];
+    this.children = new Map<Quadrant, QuadTree>();
     this.objects = [];
 
     this.maxLevels = maxLevels;
     this.splitThreshold = splitThreshold;
     this.level = level ?? 0;
+
+    this.topLeft = topLeft;
+    this.dimension = dimension;
   }
 
   public insert(id: number, dimension: Dimension2D, center: Coord2D): void {
+    const box: BoxedEntry = { id, center, dimension };
     if (this.hasChildren()) {
-      this.getIndices(boundingBox).forEach((i) =>
-        this.children[i].insert(id, dimension, center)
-      );
+      this.getQuadrants(box).forEach((quadrant) => {
+        const quadrantBox = this.children.get(quadrant);
+        quadrantBox?.insert(id, dimension, center);
+      });
       return;
     }
 
@@ -74,9 +77,10 @@ export class QuadTree {
 
     if (this.hasChildren()) {
       this.getQuadrants(boxedEntry).forEach((quadrant) => {
-        this.children
-          .get(quadrant)
-          .getNeighborIds(boxedEntry)
+        const quadrantBox = this.children.get(quadrant);
+
+        quadrantBox
+          ?.getNeighborIds(boxedEntry)
           .forEach((id) => neighbors.push(id));
       });
     }
@@ -88,15 +92,17 @@ export class QuadTree {
     const halfWidth = this.dimension.width / 2;
     const halfHeight = this.dimension.height / 2;
 
-    [
-      [Quadrant.I, { x: this.topLeft.x + halfWidth, y: this.topLeft.y }],
-      [Quadrant.II, { ...this.topLeft }],
-      [Quadrant.III, { x: this.topLeft.x, y: this.topLeft.y + halfHeight }],
+    (
       [
-        Quadrant.IV,
-        { x: this.topLeft.x + halfWidth, y: this.topLeft.y + halfHeight },
-      ],
-    ].forEach(([quadrant, pos]) => {
+        [Quadrant.I, { x: this.topLeft.x + halfWidth, y: this.topLeft.y }],
+        [Quadrant.II, { ...this.topLeft }],
+        [Quadrant.III, { x: this.topLeft.x, y: this.topLeft.y + halfHeight }],
+        [
+          Quadrant.IV,
+          { x: this.topLeft.x + halfWidth, y: this.topLeft.y + halfHeight },
+        ],
+      ] as [[Quadrant, Coord2D]]
+    ).forEach(([quadrant, pos]) => {
       this.children.set(
         quadrant,
         new QuadTree(
@@ -104,34 +110,48 @@ export class QuadTree {
           { width: halfWidth, height: halfHeight },
           this.maxLevels,
           this.splitThreshold,
-          this.level + 1
-        )
+          this.level + 1,
+        ),
       );
     });
   }
 
-  private getQuandrants(boxedEntry: BoxedEntry): Quadrant[] {
+  private getQuadrants(boxedEntry: BoxedEntry): Quadrant[] {
     const treeCenter: Coord2D = {
       x: this.topLeft.x + this.dimension.width / 2,
       y: this.topLeft.y + this.dimension.height / 2,
     };
 
-    return [
-      [Quadrant.I, (x, y) => x >= treeCenter.x && y < treeCenter.y],
-      [Quadrant.II, (x, y) => x < treeCenter.x && y < treeCenter.y],
-      [Quadrant.III, (x, y) => x < treeCenter.x && y >= treeCenter.y],
-      [Quadrant.IV, (x, y) => x >= treeCenter.x && y >= treeCenter.y],
-    ]
+    return (
+      [
+        [
+          Quadrant.I,
+          (x: number, y: number) => x >= treeCenter.x && y < treeCenter.y,
+        ],
+        [
+          Quadrant.II,
+          (x: number, y: number) => x < treeCenter.x && y < treeCenter.y,
+        ],
+        [
+          Quadrant.III,
+          (x: number, y: number) => x < treeCenter.x && y >= treeCenter.y,
+        ],
+        [
+          Quadrant.IV,
+          (x: number, y: number) => x >= treeCenter.x && y >= treeCenter.y,
+        ],
+      ] as [[Quadrant, (x: number, y: number) => boolean]]
+    )
       .filter(
         ([_quadrant, condition]) =>
           condition(
             boxedEntry.center.x + boxedEntry.dimension.width / 2,
-            boxedEntry.center.y + boxedEntry.dimension.height / 2
+            boxedEntry.center.y + boxedEntry.dimension.height / 2,
           ) ||
           condition(
             boxedEntry.center.x - boxedEntry.dimension.width / 2,
-            boxedEntry.center.y - boxedEntry.dimension.height / 2
-          )
+            boxedEntry.center.y - boxedEntry.dimension.height / 2,
+          ),
       )
       .map(([quadrant]) => quadrant);
   }
@@ -139,9 +159,12 @@ export class QuadTree {
   private realignObjects(): void {
     this.objects.forEach((boxedEntry) => {
       this.getQuadrants(boxedEntry).forEach((direction) => {
-        this.children
-          .get(direction)
-          .insert(boxedEntry.id, boxedEntry.dimension, boxedEntry.center);
+        const quadrant = this.children.get(direction);
+        quadrant?.insert(
+          boxedEntry.id,
+          boxedEntry.dimension,
+          boxedEntry.center,
+        );
       });
     });
 
@@ -149,6 +172,6 @@ export class QuadTree {
   }
 
   private hasChildren() {
-    return this.children && this.children.length > 0;
+    return this.children && this.children.size > 0;
   }
 }
diff --git a/engine/systems/Collision.ts b/engine/systems/Collision.ts
index 846a95a..2bba03b 100644
--- a/engine/systems/Collision.ts
+++ b/engine/systems/Collision.ts
@@ -5,7 +5,7 @@ import {
   ComponentNames,
   Jump,
   Velocity,
-  Moment,
+  Forces,
 } from "../components";
 import { Game } from "../Game";
 import { PhysicsConstants } from "../config";
@@ -30,60 +30,64 @@ export class Collision extends System {
       { x: 0, y: 0 },
       screenDimensions,
       Collision.QUADTREE_MAX_LEVELS,
-      Collision.QUADTREE_SPLIT_THRESHOLD
+      Collision.QUADTREE_SPLIT_THRESHOLD,
     );
   }
 
-  public update(dt: number, game: Game) {
+  public update(_dt: number, game: Game) {
     // rebuild the quadtree
     this.quadTree.clear();
 
     const entitiesToAddToQuadtree: Entity[] = [];
 
     Collision.COLLIDABLE_COMPONENT_NAMES.map((componentName) =>
-      game.componentEntities.get(componentName)
-    ).forEach((entityIds?: Set<number>) =>
-      entityIds?.forEach((id) => {
-        const entity = game.entities.get(id);
-        if (!entity.hasComponent(ComponentNames.BoundingBox)) {
-          return;
-        }
-        entitiesToAddToQuadtree.push(entity);
-      })
+      game.componentEntities.get(componentName),
+    ).forEach(
+      (entityIds?: Set<number>) =>
+        entityIds?.forEach((id) => {
+          const entity = game.entities.get(id);
+          if (!entity || !entity.hasComponent(ComponentNames.BoundingBox)) {
+            return;
+          }
+          entitiesToAddToQuadtree.push(entity);
+        }),
     );
 
     entitiesToAddToQuadtree.forEach((entity) => {
       const boundingBox = entity.getComponent<BoundingBox>(
-        ComponentNames.BoundingBox
+        ComponentNames.BoundingBox,
       );
 
-      this.quadTree.insert(
-        entity.id,
-        boundingBox.dimension,
-        boundingBox.center
-      );
+      let dimension = { ...boundingBox.dimension };
+      if (boundingBox.rotation != 0) {
+        dimension = boundingBox.getOutscribedBoxDims();
+      }
+
+      this.quadTree.insert(entity.id, dimension, boundingBox.center);
     });
 
     // find colliding entities and perform collisions
     const collidingEntities = this.getCollidingEntities(
       entitiesToAddToQuadtree,
-      game.entities
+      game,
     );
 
     collidingEntities.forEach(([entityAId, entityBId]) => {
       const [entityA, entityB] = [entityAId, entityBId].map((id) =>
-        game.entities.get(id)
+        game.entities.get(id),
       );
-      this.performCollision(entityA, entityB);
+      if (entityA && entityB) {
+        this.performCollision(entityA, entityB);
+      }
     });
   }
 
   private performCollision(entityA: Entity, entityB: Entity) {
     const [entityABoundingBox, entityBBoundingBox] = [entityA, entityB].map(
-      (entity) => entity.getComponent<BoundingBox>(ComponentNames.BoundingBox)
+      (entity) => entity.getComponent<BoundingBox>(ComponentNames.BoundingBox),
     );
 
-    let velocity: Velocity;
+    let velocity = new Velocity();
     if (entityA.hasComponent(ComponentNames.Velocity)) {
       velocity = entityA.getComponent<Velocity>(ComponentNames.Velocity);
     }
@@ -92,17 +96,16 @@ export class Collision extends System {
       entityA.hasComponent(ComponentNames.Collide) &&
       entityB.hasComponent(ComponentNames.TopCollidable) &&
       entityABoundingBox.center.y <= entityBBoundingBox.center.y &&
-      velocity &&
       velocity.dCartesian.dy >= 0 // don't apply "floor" logic when coming through the bottom
     ) {
       if (entityBBoundingBox.rotation != 0) {
         throw new Error(
-          `entity with id ${entityB.id} has TopCollidable component and a non-zero rotation. that is not (yet) supported.`
+          `entity with id ${entityB.id} has TopCollidable component and a non-zero rotation. that is not (yet) supported.`,
         );
       }
 
       // remove previous velocity in the y axis
-      velocity.dCartesian.dy = 0;
+      if (velocity) velocity.dCartesian.dy = 0;
 
       // apply normal force
       if (entityA.hasComponent(ComponentNames.Gravity)) {
@@ -110,7 +113,8 @@ export class Collision extends System {
         const F_n = -mass * PhysicsConstants.GRAVITY;
 
         entityA.getComponent<Forces>(ComponentNames.Forces).forces.push({
-          fCartesian: { fy: F_n },
+          fCartesian: { fy: F_n, fx: 0 },
+          torque: 0,
         });
       }
 
@@ -128,31 +132,35 @@ export class Collision extends System {
 
   private getCollidingEntities(
     collidableEntities: Entity[],
-    entityMap: Map<number, Entity>
+    game: Game,
   ): [number, number][] {
-    const collidingEntityIds: [number, number] = [];
+    const collidingEntityIds: [number, number][] = [];
 
     for (const entity of collidableEntities) {
       const boundingBox = entity.getComponent<BoundingBox>(
-        ComponentNames.BoundingBox
+        ComponentNames.BoundingBox,
       );
 
-      this.quadTree
+      const neighborIds = this.quadTree
         .getNeighborIds({
           id: entity.id,
           dimension: boundingBox.dimension,
           center: boundingBox.center,
         })
-        .filter((neighborId) => neighborId != entity.id)
-        .forEach((neighborId) => {
-          const neighborBoundingBox = entityMap
-            .get(neighborId)
-            .getComponent<BoundingBox>(ComponentNames.BoundingBox);
+        .filter((neighborId) => neighborId != entity.id);
 
-          if (boundingBox.isCollidingWith(neighborBoundingBox)) {
-            collidingEntityIds.push([entity.id, neighborId]);
-          }
-        });
+      neighborIds.forEach((neighborId) => {
+        const neighbor = game.getEntity(neighborId);
+        if (!neighbor) return;
+
+        const neighborBoundingBox = neighbor.getComponent<BoundingBox>(
+          ComponentNames.BoundingBox,
+        );
+
+        if (boundingBox.isCollidingWith(neighborBoundingBox)) {
+          collidingEntityIds.push([entity.id, neighborId]);
+        }
+      });
     }
 
     return collidingEntityIds;
@@ -161,55 +169,45 @@ export class Collision extends System {
   // ramblings: https://excalidraw.com/#json=z-xD86Za4a3duZuV2Oky0,KaGe-5iHJu1Si8inEo4GLQ
   private getDyToPushOutOfFloor(
     entityBoundingBox: BoundingBox,
-    floorBoundingBox: BoundingBox
+    floorBoundingBox: BoundingBox,
   ): number {
     const {
-      rotation,
-      center: { x, y },
       dimension: { width, height },
+      center: { x },
     } = entityBoundingBox;
 
-    let rads = rotation * (Math.PI / 180);
-    if (rads >= Math.PI) {
-      rads -= Math.PI; // we have symmetry so we can skip two cases
-    }
+    const outScribedRectangle = entityBoundingBox.getOutscribedBoxDims();
 
-    let boundedCollisionX = 0; // bounded x on the surface from width
-    let clippedX = 0; // x coordinate of the vertex below the surface
-    let outScribedRectangleHeight, dy, dx;
+    let rads = entityBoundingBox.getRotationInPiOfUnitCircle();
+    let dx = (width * Math.cos(rads) - height * Math.sin(rads)) / 2;
 
-    if (rads <= Math.PI / 2) {
-      dx = (width * Math.cos(rads) - height * Math.sin(rads)) / 2;
-      outScribedRectangleHeight =
-        width * Math.sin(rads) + height * Math.cos(rads);
-    } else if (rads <= Math.PI) {
+    if (rads >= Math.PI / 2) {
       rads -= Math.PI / 2;
       dx = (height * Math.cos(rads) - width * Math.sin(rads)) / 2;
-      outScribedRectangleHeight =
-        width * Math.cos(rads) + height * Math.sin(rads);
     }
 
+    const clippedX = x + dx; // x coordinate of the vertex below the surface (if existant)
+    let boundedCollisionX = 0; // bounded x on the surface from width
+
     if (x >= floorBoundingBox.center.x) {
-      clippedX = x + dx;
       boundedCollisionX = Math.min(
         floorBoundingBox.center.x + floorBoundingBox.dimension.width / 2,
-        clippedX
+        clippedX,
       );
       return (
-        outScribedRectangleHeight / 2 -
+        outScribedRectangle.height / 2 -
         Math.max((clippedX - boundedCollisionX) * Math.tan(rads), 0)
       );
     }
 
-    clippedX = x - dx;
     boundedCollisionX = Math.max(
       floorBoundingBox.center.x - floorBoundingBox.dimension.width / 2,
-      clippedX
+      clippedX,
     );
 
     return (
-      outScribedRectangleHeight / 2 -
-      Math.max((boundedCollisionX - clippedX) * Math.tan(rads), 0)
+      outScribedRectangle.height / 2 -
+      Math.max((boundedCollisionX - clippedX) * Math.tan(Math.PI / 2 - rads), 0)
     );
   }
 }
diff --git a/engine/systems/FacingDirection.ts b/engine/systems/FacingDirection.ts
index c6513ac..4426ab6 100644
--- a/engine/systems/FacingDirection.ts
+++ b/engine/systems/FacingDirection.ts
@@ -2,9 +2,9 @@ import {
   ComponentNames,
   Velocity,
   FacingDirection as FacingDirectionComponent,
+  Control,
 } from "../components";
 import { Game } from "../Game";
-import type { Entity } from "../entities";
 import { System, SystemNames } from "./";
 
 export class FacingDirection extends System {
@@ -13,24 +13,31 @@ export class FacingDirection extends System {
   }
 
   public update(_dt: number, game: Game) {
-    game.componentEntities
-      .get(ComponentNames.FacingDirection)
-      ?.forEach((entityId) => {
-        const entity = game.entities.get(entityId);
+    game.forEachEntityWithComponent(
+      ComponentNames.FacingDirection,
+      (entity) => {
         if (!entity.hasComponent(ComponentNames.Velocity)) {
           return;
         }
 
+        const totalVelocity: Velocity = new Velocity();
+        const control = entity.getComponent<Control>(ComponentNames.Control);
         const velocity = entity.getComponent<Velocity>(ComponentNames.Velocity);
+        totalVelocity.add(velocity);
+        if (control) {
+          totalVelocity.add(control.controlVelocity);
+        }
+
         const facingDirection = entity.getComponent<FacingDirectionComponent>(
-          ComponentNames.FacingDirection
+          ComponentNames.FacingDirection,
         );
 
-        if (velocity.dCartesian.dx > 0) {
+        if (totalVelocity.dCartesian.dx > 0) {
           entity.addComponent(facingDirection.facingRightSprite);
-        } else if (velocity.dCartesian.dx < 0) {
+        } else if (totalVelocity.dCartesian.dx < 0) {
           entity.addComponent(facingDirection.facingLeftSprite);
         }
-      });
+      },
+    );
   }
 }
diff --git a/engine/systems/Input.ts b/engine/systems/Input.ts
index 4272ec8..4aa9844 100644
--- a/engine/systems/Input.ts
+++ b/engine/systems/Input.ts
@@ -1,21 +1,16 @@
 import {
   Jump,
   Forces,
-  Acceleration,
   ComponentNames,
   Velocity,
   Mass,
+  Control,
 } from "../components";
 import { Game } from "../Game";
 import { KeyConstants, PhysicsConstants } from "../config";
-import type { Entity } from "../entities";
 import { Action } from "../interfaces";
 import { System, SystemNames } from "./";
 
-/**
- * TODO: Make velocities reset on each game loop (as similar to acceleration)
- *   - Then, we can add / remove velocity on update instead of just setting it and praying it's not modified externally
- */
 export class Input extends System {
   private keys: Set<string>;
   private actionTimeStamps: Map<Action, number>;
@@ -23,7 +18,7 @@ export class Input extends System {
   constructor() {
     super(SystemNames.Input);
 
-    this.keys = new Set<number>();
+    this.keys = new Set<string>();
     this.actionTimeStamps = new Map<Action, number>();
   }
 
@@ -35,51 +30,52 @@ export class Input extends System {
     this.keys.delete(key);
   }
 
-  private hasSomeKey(keys: string[]): boolean {
-    return keys.some((key) => this.keys.has(key));
+  private hasSomeKey(keys?: string[]): boolean {
+    if (keys) {
+      return keys.some((key) => this.keys.has(key));
+    }
+    return false;
   }
 
-  public update(dt: number, game: Game) {
-    game.componentEntities.get(ComponentNames.Control)?.forEach((entityId) => {
-      const entity = game.entities.get(entityId);
-      if (!entity.hasComponent(ComponentNames.Velocity)) {
-        return;
-      }
-
-      const velocity = entity.getComponent<Velocity>(ComponentNames.Velocity);
+  public update(_dt: number, game: Game) {
+    game.forEachEntityWithComponent(ComponentNames.Control, (entity) => {
+      const control = entity.getComponent<Control>(ComponentNames.Control);
 
       if (this.hasSomeKey(KeyConstants.ActionKeys.get(Action.MOVE_RIGHT))) {
-        velocity.dCartesian.dx = PhysicsConstants.PLAYER_MOVE_VEL;
-      } else if (
-        this.hasSomeKey(KeyConstants.ActionKeys.get(Action.MOVE_LEFT))
-      ) {
-        velocity.dCartesian.dx = -PhysicsConstants.PLAYER_MOVE_VEL;
-      } else {
-        velocity.dCartesian.dx = 0;
+        control.controlVelocity.dCartesian.dx +=
+          PhysicsConstants.PLAYER_MOVE_VEL;
       }
-    });
 
-    game.componentEntities.get(ComponentNames.Jump)?.forEach((entityId) => {
-      const entity = game.entities.get(entityId);
-      const jump = entity.getComponent<Jump>(ComponentNames.Jump);
-      const velocity = entity.getComponent<Velocity>(ComponentNames.Velocity);
+      if (this.hasSomeKey(KeyConstants.ActionKeys.get(Action.MOVE_LEFT))) {
+        control.controlVelocity.dCartesian.dx +=
+          -PhysicsConstants.PLAYER_MOVE_VEL;
+      }
 
-      if (this.hasSomeKey(KeyConstants.ActionKeys.get(Action.JUMP))) {
-        if (jump.canJump) {
-          this.actionTimeStamps.set(Action.JUMP, performance.now());
+      if (entity.hasComponent(ComponentNames.Jump)) {
+        const velocity = entity.getComponent<Velocity>(ComponentNames.Velocity);
+        const jump = entity.getComponent<Jump>(ComponentNames.Jump);
 
-          velocity.dCartesian.dy = PhysicsConstants.PLAYER_JUMP_INITIAL_VEL;
-          jump.canJump = false;
-        }
+        if (this.hasSomeKey(KeyConstants.ActionKeys.get(Action.JUMP))) {
+          if (jump.canJump) {
+            this.actionTimeStamps.set(Action.JUMP, performance.now());
 
-        if (
-          performance.now() - this.actionTimeStamps.get(Action.JUMP) <
-          PhysicsConstants.MAX_JUMP_TIME_MS
-        ) {
-          const mass = entity.getComponent<Mass>(ComponentNames.Mass).mass;
-          entity.getComponent<Forces>(ComponentNames.Forces)?.forces.push({
-            fCartesian: { fy: mass * PhysicsConstants.PLAYER_JUMP_ACC },
-          });
+            velocity.dCartesian.dy += PhysicsConstants.PLAYER_JUMP_INITIAL_VEL;
+            jump.canJump = false;
+          }
+
+          if (
+            performance.now() - (this.actionTimeStamps.get(Action.JUMP) || 0) <
+            PhysicsConstants.MAX_JUMP_TIME_MS
+          ) {
+            const mass = entity.getComponent<Mass>(ComponentNames.Mass).mass;
+            entity.getComponent<Forces>(ComponentNames.Forces)?.forces.push({
+              fCartesian: {
+                fy: mass * PhysicsConstants.PLAYER_JUMP_ACC,
+                fx: 0,
+              },
+              torque: 0,
+            });
+          }
         }
       }
     });
diff --git a/engine/systems/Physics.ts b/engine/systems/Physics.ts
index 7edeb41..38962a6 100644
--- a/engine/systems/Physics.ts
+++ b/engine/systems/Physics.ts
@@ -1,6 +1,5 @@
 import { System, SystemNames } from ".";
 import {
-  Acceleration,
   BoundingBox,
   ComponentNames,
   Forces,
@@ -8,9 +7,10 @@ import {
   Velocity,
   Mass,
   Jump,
+  Moment,
+  Control,
 } from "../components";
 import { PhysicsConstants } from "../config";
-import type { Entity } from "../entities";
 import type { Force2D } from "../interfaces";
 import { Game } from "../Game";
 
@@ -20,14 +20,12 @@ export class Physics extends System {
   }
 
   public update(dt: number, game: Game): void {
-    game.componentEntities.get(ComponentNames.Forces)?.forEach((entityId) => {
-      const entity = game.entities.get(entityId);
-
+    game.forEachEntityWithComponent(ComponentNames.Forces, (entity) => {
       const mass = entity.getComponent<Mass>(ComponentNames.Mass).mass;
       const forces = entity.getComponent<Forces>(ComponentNames.Forces).forces;
       const velocity = entity.getComponent<Velocity>(ComponentNames.Velocity);
       const inertia = entity.getComponent<Moment>(
-        ComponentNames.Moment
+        ComponentNames.Moment,
       ).inertia;
 
       // F_g = mg, applied only until terminal velocity is reached
@@ -37,7 +35,9 @@ export class Physics extends System {
           forces.push({
             fCartesian: {
               fy: mass * PhysicsConstants.GRAVITY,
+              fx: 0,
             },
+            torque: 0,
           });
         }
       }
@@ -51,7 +51,7 @@ export class Physics extends System {
           },
           torque: accum.torque + (torque ?? 0),
         }),
-        { fCartesian: { fx: 0, fy: 0 }, torque: 0 }
+        { fCartesian: { fx: 0, fy: 0 }, torque: 0 },
       );
 
       // integrate accelerations
@@ -62,6 +62,7 @@ export class Physics extends System {
       velocity.dCartesian.dx += ddx * dt;
       velocity.dCartesian.dy += ddy * dt;
       velocity.dTheta += (sumOfForces.torque * dt) / inertia;
+
       // clear the forces
       entity.getComponent<Forces>(ComponentNames.Forces).forces = [];
 
@@ -71,11 +72,17 @@ export class Physics extends System {
       }
     });
 
-    game.componentEntities.get(ComponentNames.Velocity)?.forEach((entityId) => {
-      const entity = game.entities.get(entityId);
-      const velocity = entity.getComponent<Velocity>(ComponentNames.Velocity);
+    game.forEachEntityWithComponent(ComponentNames.Velocity, (entity) => {
+      const velocity: Velocity = new Velocity();
+      const control = entity.getComponent<Control>(ComponentNames.Control);
+
+      velocity.add(entity.getComponent<Velocity>(ComponentNames.Velocity));
+      if (control) {
+        velocity.add(control.controlVelocity);
+      }
+
       const boundingBox = entity.getComponent<BoundingBox>(
-        ComponentNames.BoundingBox
+        ComponentNames.BoundingBox,
       );
 
       // integrate velocity
@@ -86,6 +93,11 @@ export class Physics extends System {
         (boundingBox.rotation < 0
           ? 360 + boundingBox.rotation
           : boundingBox.rotation) % 360;
+
+      // clear the control velocity
+      if (control) {
+        control.controlVelocity = new Velocity();
+      }
     });
   }
 }
diff --git a/engine/systems/Render.ts b/engine/systems/Render.ts
index b5479e1..9bb4091 100644
--- a/engine/systems/Render.ts
+++ b/engine/systems/Render.ts
@@ -1,8 +1,6 @@
 import { System, SystemNames } from ".";
 import { BoundingBox, ComponentNames, Sprite } from "../components";
-import type { Entity } from "../entities";
 import { Game } from "../Game";
-import type { DrawArgs } from "../interfaces";
 import { clamp } from "../utils";
 
 export class Render extends System {
@@ -16,39 +14,36 @@ export class Render extends System {
   public update(dt: number, game: Game) {
     this.ctx.clearRect(0, 0, this.ctx.canvas.width, this.ctx.canvas.height);
 
-    game.componentEntities.get(ComponentNames.Sprite)?.forEach((entityId) => {
-      const entity = game.entities.get(entityId);
+    game.forEachEntityWithComponent(ComponentNames.Sprite, (entity) => {
       const sprite = entity.getComponent<Sprite>(ComponentNames.Sprite);
       sprite.update(dt);
 
-      let drawArgs: DrawArgs;
-      if (entity.hasComponent(ComponentNames.BoundingBox)) {
-        const boundingBox = entity.getComponent<BoundingBox>(
-          ComponentNames.BoundingBox
-        );
+      const boundingBox = entity.getComponent<BoundingBox>(
+        ComponentNames.BoundingBox,
+      );
 
-        // don't render if we're outside the screen
-        if (
-          clamp(
-            boundingBox.center.y,
-            -boundingBox.dimension.height / 2,
-            this.ctx.canvas.height + boundingBox.dimension.height / 2
-          ) != boundingBox.center.y ||
-          clamp(
-            boundingBox.center.x,
-            -boundingBox.dimension.width / 2,
-            this.ctx.canvas.width + boundingBox.dimension.width / 2
-          ) != boundingBox.center.x
-        ) {
-          return;
-        }
-
-        drawArgs = {
-          center: boundingBox.center,
-          dimension: boundingBox.dimension,
-          rotation: boundingBox.rotation,
-        };
+      // don't render if we're outside the screen
+      if (
+        clamp(
+          boundingBox.center.y,
+          -boundingBox.dimension.height / 2,
+          this.ctx.canvas.height + boundingBox.dimension.height / 2,
+        ) != boundingBox.center.y ||
+        clamp(
+          boundingBox.center.x,
+          -boundingBox.dimension.width / 2,
+          this.ctx.canvas.width + boundingBox.dimension.width / 2,
+        ) != boundingBox.center.x
+      ) {
+        return;
       }
+
+      const drawArgs = {
+        center: boundingBox.center,
+        dimension: boundingBox.dimension,
+        rotation: boundingBox.rotation,
+      };
+
       sprite.draw(this.ctx, drawArgs);
     });
   }
diff --git a/engine/systems/System.ts b/engine/systems/System.ts
index 1aad285..8b00dc5 100644
--- a/engine/systems/System.ts
+++ b/engine/systems/System.ts
@@ -1,4 +1,3 @@
-import { Entity } from "../entities";
 import { Game } from "../Game";
 
 export abstract class System {
diff --git a/engine/systems/WallBounds.ts b/engine/systems/WallBounds.ts
index 6ea2267..a0d4a9c 100644
--- a/engine/systems/WallBounds.ts
+++ b/engine/systems/WallBounds.ts
@@ -14,23 +14,16 @@ export class WallBounds extends System {
   }
 
   public update(_dt: number, game: Game) {
-    game.componentEntities
-      .get(ComponentNames.WallBounded)
-      ?.forEach((entityId) => {
-        const entity = game.entities.get(entityId);
-        if (!entity.hasComponent(ComponentNames.BoundingBox)) {
-          return;
-        }
+    game.forEachEntityWithComponent(ComponentNames.WallBounded, (entity) => {
+      const boundingBox = entity.getComponent<BoundingBox>(
+        ComponentNames.BoundingBox,
+      );
 
-        const boundingBox = entity.getComponent<BoundingBox>(
-          ComponentNames.BoundingBox
-        );
-
-        boundingBox.center.x = clamp(
-          boundingBox.center.x,
-          boundingBox.dimension.width / 2,
-          this.screenWidth - boundingBox.dimension.width / 2
-        );
-      });
+      boundingBox.center.x = clamp(
+        boundingBox.center.x,
+        boundingBox.dimension.width / 2,
+        this.screenWidth - boundingBox.dimension.width / 2,
+      );
+    });
   }
 }
diff --git a/engine/utils/index.ts b/engine/utils/index.ts
index 4e465c2..82a0d05 100644
--- a/engine/utils/index.ts
+++ b/engine/utils/index.ts
@@ -1,4 +1,3 @@
 export * from "./rotateVector";
-export * from "./normalizeVector";
 export * from "./dotProduct";
 export * from "./clamp";
diff --git a/engine/utils/normalizeVector.ts b/engine/utils/normalizeVector.ts
deleted file mode 100644
index e6dfd7f..0000000
--- a/engine/utils/normalizeVector.ts
+++ /dev/null
@@ -1,8 +0,0 @@
-import type { Coord2D } from "../interfaces";
-
-export const normalizeVector = (vector: Coord2D): Coord2D => {
-  const { x, y } = vector;
-  const length = Math.sqrt(x * x + y * y);
-
-  return { x: x / length, y: y / length };
-};
diff --git a/server/src/server.ts b/server/src/server.ts
index f699ea9..74d901b 100644
--- a/server/src/server.ts
+++ b/server/src/server.ts
@@ -1,21 +1,17 @@
 import { Game } from "../../engine/Game";
 import { Floor, Player } from "../../engine/entities";
-import {
-  WallBounds,
-  FacingDirection,
-  Physics,
-  Input,
-  Collision,
-} from "../../engine/systems";
+import { WallBounds, Physics, Collision } from "../../engine/systems";
 import { Miscellaneous } from "../../engine/config";
 
 const TICK_RATE = 60 / 1000;
 
 const game = new Game();
 
-[new Physics(), new Collision(), new WallBounds(Miscellaneous.WIDTH)].forEach(
-  (system) => game.addSystem(system)
-);
+[
+  new Physics(),
+  new Collision({ width: Miscellaneous.WIDTH, height: Miscellaneous.HEIGHT }),
+  new WallBounds(Miscellaneous.WIDTH),
+].forEach((system) => game.addSystem(system));
 
 [new Floor(160), new Player()].forEach((entity) => game.addEntity(entity));