a bit of refactoring; importing engine into bun for server

16 files changed, 342 insertions, 0 deletions

diff --git a/engine/components/BoundingBox.ts b/engine/components/BoundingBox.ts
new file mode 100644
index 0000000..2b1d648
--- /dev/null
+++ b/engine/components/BoundingBox.ts
@@ -0,0 +1,97 @@
+import { Component, ComponentNames } from ".";
+import type { Coord2D, Dimension2D } from "../interfaces";
+import { dotProduct, rotateVector, normalizeVector } from "../utils";
+
+export class BoundingBox extends Component {
+  public center: Coord2D;
+  public dimension: Dimension2D;
+  public rotation: number;
+
+  constructor(center: Coord2D, dimension: Dimension2D, rotation?: number) {
+    super(ComponentNames.BoundingBox);
+
+    this.center = center;
+    this.dimension = dimension;
+    this.rotation = rotation ?? 0;
+  }
+
+  public isCollidingWith(box: BoundingBox): boolean {
+    const boxes = [this.getVertices(), box.getVertices()];
+    for (const poly of boxes) {
+      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 };
+
+        const [[minThis, maxThis], [minBox, maxBox]] = boxes.map((box) =>
+          box.reduce(
+            ([min, max], vertex) => {
+              const projection = dotProduct(normal, vertex);
+              return [Math.min(min, projection), Math.max(max, projection)];
+            },
+            [Infinity, -Infinity]
+          )
+        );
+
+        if (maxThis < minBox || maxBox < minThis) return false;
+      }
+    }
+
+    return true;
+  }
+
+  public getVertices(): Coord2D[] {
+    return [
+      { x: -this.dimension.width / 2, y: -this.dimension.height / 2 },
+      { x: -this.dimension.width / 2, y: this.dimension.height / 2 },
+      { x: this.dimension.width / 2, y: this.dimension.height / 2 },
+      { x: this.dimension.width / 2, y: -this.dimension.height / 2 },
+    ]
+      .map((vertex) => rotateVector(vertex, this.rotation))
+      .map((vertex) => {
+        return {
+          x: vertex.x + this.center.x,
+          y: vertex.y + this.center.y,
+        };
+      });
+  }
+
+  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),
+        })
+      );
+    }
+
+    return axes;
+  }
+
+  private project(axis: Coord2D): [number, number] {
+    const corners = this.getCornersRelativeToCenter();
+    let [min, max] = [Infinity, -Infinity];
+
+    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,
+      };
+      const projection = dotProduct(translated, axis);
+
+      min = Math.min(projection, min);
+      max = Math.max(projection, max);
+    }
+
+    return [min, max];
+  }
+}
diff --git a/engine/components/Collide.ts b/engine/components/Collide.ts
new file mode 100644
index 0000000..889ecf8
--- /dev/null
+++ b/engine/components/Collide.ts
@@ -0,0 +1,7 @@
+import { Component, ComponentNames } from ".";
+
+export class Collide extends Component {
+  constructor() {
+    super(ComponentNames.Collide);
+  }
+}
diff --git a/engine/components/Component.ts b/engine/components/Component.ts
new file mode 100644
index 0000000..7331982
--- /dev/null
+++ b/engine/components/Component.ts
@@ -0,0 +1,7 @@
+export abstract class Component {
+  public readonly name: string;
+
+  constructor(name: string) {
+    this.name = name;
+  }
+}
diff --git a/engine/components/Control.ts b/engine/components/Control.ts
new file mode 100644
index 0000000..094ef1c
--- /dev/null
+++ b/engine/components/Control.ts
@@ -0,0 +1,7 @@
+import { Component, ComponentNames } from ".";
+
+export class Control extends Component {
+  constructor() {
+    super(ComponentNames.Control);
+  }
+}
diff --git a/engine/components/FacingDirection.ts b/engine/components/FacingDirection.ts
new file mode 100644
index 0000000..1c701a3
--- /dev/null
+++ b/engine/components/FacingDirection.ts
@@ -0,0 +1,13 @@
+import { Component, ComponentNames, Sprite } from ".";
+
+export class FacingDirection extends Component {
+  public readonly facingLeftSprite: Sprite;
+  public readonly facingRightSprite: Sprite;
+
+  constructor(facingLeftSprite: Sprite, facingRightSprite: Sprite) {
+    super(ComponentNames.FacingDirection);
+
+    this.facingLeftSprite = facingLeftSprite;
+    this.facingRightSprite = facingRightSprite;
+  }
+}
diff --git a/engine/components/Forces.ts b/engine/components/Forces.ts
new file mode 100644
index 0000000..bf540a1
--- /dev/null
+++ b/engine/components/Forces.ts
@@ -0,0 +1,17 @@
+import type { Accel2D, Force2D } from "../interfaces";
+import { Component } from "./Component";
+import { ComponentNames } from ".";
+
+/**
+ * A list of forces and torque, (in newtons, and newton-meters respectively)
+ * to apply on one Physics system update (after which, they are cleared).
+ */
+export class Forces extends Component {
+  public forces: Force2D[];
+
+  constructor(forces?: Force2D[]) {
+    super(ComponentNames.Forces);
+
+    this.forces = forces ?? [];
+  }
+}
diff --git a/engine/components/Gravity.ts b/engine/components/Gravity.ts
new file mode 100644
index 0000000..89fcb67
--- /dev/null
+++ b/engine/components/Gravity.ts
@@ -0,0 +1,13 @@
+import { ComponentNames, Component } from ".";
+
+export class Gravity extends Component {
+  private static DEFAULT_TERMINAL_VELOCITY = 5;
+
+  public terminalVelocity: number;
+
+  constructor(terminalVelocity?: number) {
+    super(ComponentNames.Gravity);
+    this.terminalVelocity =
+      terminalVelocity ?? Gravity.DEFAULT_TERMINAL_VELOCITY;
+  }
+}
diff --git a/engine/components/Jump.ts b/engine/components/Jump.ts
new file mode 100644
index 0000000..0b40767
--- /dev/null
+++ b/engine/components/Jump.ts
@@ -0,0 +1,10 @@
+import { Component, ComponentNames } from ".";
+
+export class Jump extends Component {
+  public canJump: boolean;
+
+  constructor() {
+    super(ComponentNames.Jump);
+    this.canJump = false;
+  }
+}
diff --git a/engine/components/Mass.ts b/engine/components/Mass.ts
new file mode 100644
index 0000000..daa2d71
--- /dev/null
+++ b/engine/components/Mass.ts
@@ -0,0 +1,10 @@
+import { Component, ComponentNames } from ".";
+
+export class Mass extends Component {
+  public mass: number;
+
+  constructor(mass: number) {
+    super(ComponentNames.Mass);
+    this.mass = mass;
+  }
+}
diff --git a/engine/components/Moment.ts b/engine/components/Moment.ts
new file mode 100644
index 0000000..3d0dd2f
--- /dev/null
+++ b/engine/components/Moment.ts
@@ -0,0 +1,10 @@
+import { Component, ComponentNames } from ".";
+
+export class Moment extends Component {
+  public inertia: number;
+
+  constructor(inertia: number) {
+    super(ComponentNames.Moment);
+    this.inertia = inertia;
+  }
+}
diff --git a/engine/components/Sprite.ts b/engine/components/Sprite.ts
new file mode 100644
index 0000000..90e1389
--- /dev/null
+++ b/engine/components/Sprite.ts
@@ -0,0 +1,92 @@
+import { Component, ComponentNames } from ".";
+import type { Dimension2D, DrawArgs, Coord2D } from "../interfaces";
+
+export class Sprite extends Component {
+  private sheet: HTMLImageElement;
+
+  private spriteImgPos: Coord2D;
+  private spriteImgDimensions: Dimension2D;
+
+  private msPerFrame: number;
+  private msSinceLastFrame: number;
+  private currentFrame: number;
+  private numFrames: number;
+
+  constructor(
+    sheet: HTMLImageElement,
+    spriteImgPos: Coord2D,
+    spriteImgDimensions: Dimension2D,
+    msPerFrame: number,
+    numFrames: number
+  ) {
+    super(ComponentNames.Sprite);
+
+    this.sheet = sheet;
+    this.spriteImgPos = spriteImgPos;
+    this.spriteImgDimensions = spriteImgDimensions;
+    this.msPerFrame = msPerFrame;
+    this.numFrames = numFrames;
+
+    this.msSinceLastFrame = 0;
+    this.currentFrame = 0;
+  }
+
+  public update(dt: number) {
+    this.msSinceLastFrame += dt;
+    if (this.msSinceLastFrame >= this.msPerFrame) {
+      this.currentFrame = (this.currentFrame + 1) % this.numFrames;
+      this.msSinceLastFrame = 0;
+    }
+  }
+
+  public draw(ctx: CanvasRenderingContext2D, drawArgs: DrawArgs) {
+    const { center, rotation, tint, opacity } = drawArgs;
+
+    ctx.save();
+    ctx.translate(center.x, center.y);
+    if (rotation != 0) {
+      ctx.rotate(rotation * (Math.PI / 180));
+    }
+    ctx.translate(-center.x, -center.y);
+
+    if (opacity) {
+      ctx.globalAlpha = opacity;
+    }
+
+    ctx.drawImage(
+      this.sheet,
+      ...this.getSpriteArgs(),
+      ...this.getDrawArgs(drawArgs)
+    );
+
+    if (tint) {
+      ctx.globalAlpha = 0.5;
+      ctx.globalCompositeOperation = "source-atop";
+      ctx.fillStyle = tint;
+      ctx.fillRect(...this.getDrawArgs(drawArgs));
+    }
+
+    ctx.restore();
+  }
+
+  private getSpriteArgs(): [sx: number, sy: number, sw: number, sh: number] {
+    return [
+      this.spriteImgPos.x + this.currentFrame * this.spriteImgDimensions.width,
+      this.spriteImgPos.y,
+      this.spriteImgDimensions.width,
+      this.spriteImgDimensions.height,
+    ];
+  }
+
+  private getDrawArgs({
+    center,
+    dimension,
+  }: DrawArgs): [dx: number, dy: number, dw: number, dh: number] {
+    return [
+      center.x - dimension.width / 2,
+      center.y - dimension.height / 2,
+      dimension.width,
+      dimension.height,
+    ];
+  }
+}
diff --git a/engine/components/TopCollidable.ts b/engine/components/TopCollidable.ts
new file mode 100644
index 0000000..7fb147d
--- /dev/null
+++ b/engine/components/TopCollidable.ts
@@ -0,0 +1,7 @@
+import { Component, ComponentNames } from ".";
+
+export class TopCollidable extends Component {
+  constructor() {
+    super(ComponentNames.TopCollidable);
+  }
+}
diff --git a/engine/components/Velocity.ts b/engine/components/Velocity.ts
new file mode 100644
index 0000000..119427d
--- /dev/null
+++ b/engine/components/Velocity.ts
@@ -0,0 +1,15 @@
+import type { Velocity2D } from "../interfaces";
+import { Component } from "./Component";
+import { ComponentNames } from ".";
+
+export class Velocity extends Component {
+  public dCartesian: Velocity2D;
+  public dTheta: number;
+
+  constructor(dCartesian: Velocity2D, dTheta: number) {
+    super(ComponentNames.Velocity);
+
+    this.dCartesian = dCartesian;
+    this.dTheta = dTheta;
+  }
+}
diff --git a/engine/components/WallBounded.ts b/engine/components/WallBounded.ts
new file mode 100644
index 0000000..5f787e1
--- /dev/null
+++ b/engine/components/WallBounded.ts
@@ -0,0 +1,7 @@
+import { Component, ComponentNames } from ".";
+
+export class WallBounded extends Component {
+  constructor() {
+    super(ComponentNames.WallBounded);
+  }
+}
diff --git a/engine/components/index.ts b/engine/components/index.ts
new file mode 100644
index 0000000..67f1259
--- /dev/null
+++ b/engine/components/index.ts
@@ -0,0 +1,15 @@
+export * from "./Component";
+export * from "./BoundingBox";
+export * from "./Velocity";
+export * from "./Forces";
+export * from "./Sprite";
+export * from "./FacingDirection";
+export * from "./Jump";
+export * from "./TopCollidable";
+export * from "./Collide";
+export * from "./Control";
+export * from "./WallBounded";
+export * from "./Gravity";
+export * from "./Mass";
+export * from "./Moment";
+export * from "./names";
diff --git a/engine/components/names.ts b/engine/components/names.ts
new file mode 100644
index 0000000..e2ee3d3
--- /dev/null
+++ b/engine/components/names.ts
@@ -0,0 +1,15 @@
+export namespace ComponentNames {
+  export const Sprite = "Sprite";
+  export const BoundingBox = "BoundingBox";
+  export const Velocity = "Velocity";
+  export const FacingDirection = "FacingDirection";
+  export const Control = "Control";
+  export const Jump = "Jump";
+  export const TopCollidable = "TopCollidable";
+  export const Collide = "Collide";
+  export const WallBounded = "WallBounded";
+  export const Gravity = "Gravity";
+  export const Forces = "Forces";
+  export const Mass = "Mass";
+  export const Moment = "Moment";
+}