Whambap

frontend/vec2.js

@@ -0,0 +1,164 @@
+export class Vector2i {
+    constructor(x = 0, y = 0) {
+        this.x = x | 0; // force int
+        this.y = y | 0;
+    }
+
+    clone() {
+        return new Vector2i(this.x, this.y);
+    }
+
+    // add another vector (mutates)
+    add(v) {
+        this.x = (this.x + v.x) | 0;
+        this.y = (this.y + v.y) | 0;
+        return this;
+    }
+
+    // subtract another vector (mutates)
+    sub(v) {
+        this.x = (this.x - v.x) | 0;
+        this.y = (this.y - v.y) | 0;
+        return this;
+    }
+
+    // multiply by scalar (mutates)
+    mul(s) {
+        this.x = (this.x * s) | 0;
+        this.y = (this.y * s) | 0;
+        return this;
+    }
+
+    // length squared (int-safe)
+    lengthSq() {
+        return (this.x * this.x + this.y * this.y) | 0;
+    }
+
+    // temporary result (non-mutating)
+    added(v) {
+        return this.clone().add(v);
+    }
+    subbed(v) {
+        return this.clone().sub(v);
+    }
+    mulled(s) {
+        return this.clone().mul(s);
+    }
+
+    // which cardinal direction are we in?
+    cardinalDirection() {
+        if (this.y === 0) {
+            if (this.x > 0) {
+                return 0;
+            }
+
+            if (this.x < 0) {
+                return 2;
+            }
+        }
+        if (this.x === 0) {
+            if (this.y > 0) {
+                return 1;
+            }
+
+            if (this.y < 0) {
+                return 3;
+            }
+        }
+    }
+
+    rotateCW(quarterTurns = 1) {
+        quarterTurns = (quarterTurns + 4) % 4;
+        if (quarterTurns === 0) {
+            return this;
+        }
+        if (quarterTurns === 1) {
+            return this.rotate270();
+        }
+        if (quarterTurns === 2) {
+            return this.rotate180();
+        }
+        if (quarterTurns === 3) {
+            return this.rotate90();
+        }
+
+        throw new Error("Logic error. How did we end up here?");
+    }
+    rotateCCW(quarterTurns = 1) {
+        quarterTurns = (quarterTurns + 4) % 4;
+        if (quarterTurns === 0) {
+            return this;
+        }
+
+        if (quarterTurns === 1) {
+            return this.rotate90();
+        }
+        if (quarterTurns === 2) {
+            return this.rotate180();
+        }
+        if (quarterTurns === 3) {
+            return this.rotate270();
+        }
+
+        throw new Error("Logic error. How did we end up here?");
+    }
+
+    // === rotations (mutating) ===
+    rotate90() {
+        // counter-clockwise
+        const x = this.x | 0;
+        this.x = -this.y | 0;
+        this.y = x | 0;
+        return this;
+    }
+
+    rotate180() {
+        this.x = -this.x | 0;
+        this.y = -this.y | 0;
+        return this;
+    }
+
+    rotate270() {
+        // clockwise
+        const x = this.x | 0;
+        this.x = this.y | 0;
+        this.y = -x | 0;
+        return this;
+    }
+
+    // === non-mutating versions ===
+    rotated90() {
+        return this.clone().rotate90();
+    }
+    rotated180() {
+        return this.clone().rotate180();
+    }
+    rotated270() {
+        return this.clone().rotate270();
+    }
+    rotatedCW(quarterTurns) {
+        return this.clone().rotateCW(quarterTurns);
+    }
+    rotatedCCW(quarterTurns) {
+        return this.clone().rotateCCW(quarterTurns);
+    }
+
+    angle() {
+        return Math.atan2(this.y, this.x); // radians
+    }
+
+    angleTo(v) {
+        const a = this.angle();
+        const b = v.angle();
+
+        let d = (b - a) % (2 * Math.PI);
+        if (d < -Math.PI) d += 2 * Math.PI;
+        if (d > Math.PI) d -= 2 * Math.PI;
+
+        return d;
+    }
+
+    toString() {
+        return `[${this.x} , ${this.y}]`;
+    }
+}