// ═══ renderer.js ═══
// ============================================================
//  RENDERER — draw order orchestration
// ============================================================

// ── MAIN RENDER ───────────────────────────────────────────────
function render() {
  const W = canvas.width, H = canvas.height;
  const cx = ARENA_CX, cy = ARENA_CY;

  // Rebuild bg cache if size changed
  if (!_bgCanvas || _bgW !== W || _bgH !== H) buildBackground(W, H);

  // Blit cached background — O(1)
  ctx.drawImage(_bgCanvas, 0, 0);

  // World layer — apply camera zoom centred on tower
  const _zoom = G.camera?.zoom ?? 1.0;
  ctx.save();
  ctx.translate(cx, cy);
  ctx.scale(_zoom, _zoom);
  ctx.translate(-cx, -cy);

  drawGrid(cx, cy);
  drawWeaponRanges(cx, cy);     // alt-hold: per-weapon range rings
  drawPortals();
  drawAoeZones();
  drawEnemyTrails();
  drawEnemies();
  drawProjectiles();
  drawChainArcs();
  drawBeams();
  drawTower(cx, cy);
  drawShield(cx, cy);
  drawParticles();
  drawFloaters();
  ctx.restore(); // end world layer

  // Mask/ring/streak operate in screen space — drawn AFTER world transform
  drawArenaMask(W, H, cx, cy, _zoom);
  drawArenaRing(cx, cy, _zoom);
  drawStreak(cx, cy);

  // UI layer — no camera transform
  clearHitRegions();
  _mountDropZones.length = 0;
  _bagDropZones.length   = 0;
  _dragRegions.length    = 0;
  drawHUD();
  drawBrokeWarning();
  drawSidePanel();
  drawInventoryOverlay();
  drawCommandOverlay();
  drawArmoryOverlay();
  drawWeaponDetailOverlay();
  checkSellHold();
  checkPrestigeHold();
  drawThreatPanel();
  drawPrestigeConfirm();
  if (G.gameOver) drawGameOverPanel();
  drawPauseOverlay();

  drawMountInteraction(cx, cy);

  drawDragGhost();   // follows cursor — screen space, no zoom
  drawTooltips();
}