[game] Walk controls (unbound)

game/vector.ts

@@ -0,0 +1,49 @@
+export interface Vec2 {
+  x: number;
+  y: number;
+}
+
+export function new_v2(x: number, y: number | undefined = undefined): Vec2 {
+  y = y || x;
+  return { x, y };
+}
+
+function vecargs(v: Vec2 | number): Vec2 {
+  if (typeof v == "number") {
+    return new_v2(v, v);
+  } else {
+    return v;
+  }
+}
+
+export function vadd(a: Vec2, b: Vec2 | number): Vec2 {
+  b = vecargs(b);
+  return { x: a.x + b.x, y: a.y + b.y };
+}
+
+export function vsub(a: Vec2, b: Vec2 | number): Vec2 {
+  b = vecargs(b);
+  return { x: a.x - b.x, y: a.y - b.y };
+}
+
+export function vmul(a: Vec2, b: Vec2 | number): Vec2 {
+  b = vecargs(b);
+  return { x: a.x * b.x, y: a.y * b.y };
+}
+
+export function vdiv(a: Vec2, b: Vec2 | number): Vec2 {
+  b = vecargs(b);
+  return { x: a.x / b.x, y: a.y / b.y };
+}
+
+export function vlen(a: Vec2): number {
+  return Math.sqrt(a.x * a.x + a.y * a.y);
+}
+
+export function vnorm(a: Vec2) {
+  const length = vlen(a);
+  if (length > 0) {
+    a.x /= length;
+    a.y /= length;
+  }
+}