the great engine refactor

1 files changed, 22 insertions, 35 deletions

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)),
+    };
   }
 }