Initial commit: Siege Protocol

Inverted tower-defense browser game — deploy enemies yourself, tower auto-kills them, pocket credits, upgrade weapons. HTML + Canvas + vanilla JS, no build step.

Co-Authored-By: claude-flow <ruv@ruv.net>

js/utils.js

@@ -0,0 +1,59 @@
+// ═══ utils.js ═══
+// ============================================================
+//  UTILS — shared pure helpers
+// ============================================================
+
+function distSq(ax, ay, bx, by) {
+  const dx = ax - bx;
+  const dy = ay - by;
+  return dx * dx + dy * dy;
+}
+
+function normalizeAngle(angle) {
+  while (angle > Math.PI) angle -= Math.PI * 2;
+  while (angle < -Math.PI) angle += Math.PI * 2;
+  return angle;
+}
+
+function shortestAngleDelta(from, to) {
+  return normalizeAngle(to - from);
+}
+
+function stepTowardAngle(current, desired, maxStep) {
+  const delta = shortestAngleDelta(current, desired);
+  if (Math.abs(delta) <= maxStep) return normalizeAngle(desired);
+  return normalizeAngle(current + Math.sign(delta) * maxStep);
+}
+
+function compactLiveArray(items, isLive) {
+  let write = 0;
+  for (let i = 0; i < items.length; i++) {
+    const item = items[i];
+    if (isLive(item)) items[write++] = item;
+  }
+  items.length = write;
+}
+
+function clamp(value, min, max) {
+  return Math.max(min, Math.min(max, value));
+}
+
+function cheapestEnemyCost() {
+  return ENEMY_DEFS.reduce((min, d) => Math.min(min, d.cost), Infinity);
+}
+
+function countAliveEnemies() {
+  let count = 0;
+  for (const e of G.enemies) if (e.alive) count++;
+  return count;
+}
+
+function getEquippedWeapons() {
+  return G.weapons.slice(0, G.tower.weaponSlots).filter(Boolean);
+}
+
+function findWeaponInstance(instanceId) {
+  for (const w of G.weapons) if (w && w.instanceId === instanceId) return w;
+  return null;
+}
+