Show warning when placing too many buildings

src/js/game/hud/hud.js

@@ -45,6 +45,7 @@ import { HUDLeverToggle } from "./parts/lever_toggle";
 import { HUDLayerPreview } from "./parts/layer_preview";
 import { HUDMinerHighlight } from "./parts/miner_highlight";
 import { HUDBetaOverlay } from "./parts/beta_overlay";
+import { HUDPerformanceWarning } from "./parts/performance_warning";
 
 export class GameHUD {
     /**
@@ -85,6 +86,7 @@ export class GameHUD {
             layerPreview: new HUDLayerPreview(this.root),
 
             minerHighlight: new HUDMinerHighlight(this.root),
+            performanceWarning: new HUDPerformanceWarning(this.root),
 
             // Typing hints
             /* typehints:start */

src/js/game/hud/parts/performance_warning.js

@@ -0,0 +1,16 @@
+import { T } from "../../../translations";
+import { BaseHUDPart } from "../base_hud_part";
+
+export class HUDPerformanceWarning extends BaseHUDPart {
+    initialize() {
+        this.warningShown = false;
+        this.root.signals.entityManuallyPlaced.add(this.checkAfterPlace, this);
+    }
+
+    checkAfterPlace() {
+        if (!this.warningShown && this.root.entityMgr.entities.length > 10000) {
+            this.root.hud.parts.dialogs.showInfo(T.dialogs.entityWarning.title, T.dialogs.entityWarning.desc);
+            this.warningShown = true;
+        }
+    }
+}