From 6ca06a6f6ff58dbf37a8927193575be89bb67dc0 Mon Sep 17 00:00:00 2001
From: TKTK123456 <103334266+TKTK123456@users.noreply.github.com>
Date: Mon, 1 Jun 2026 20:39:52 -0400
Subject: [PATCH] Sam/factory radius ghost upgrade fix (#4104)
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> **Before opening a PR:** discuss new features on
[Discord](https://discord.gg/K9zernJB5z) first, and file bugs or small
improvements as
[issues](https://github.com/openfrontio/OpenFrontIO/issues/new/choose).
You must be assigned to an `approved` issue — unsolicited PRs will be
auto-closed.

**Add approved & assigned issue number here:**

Resolves #4059

## Description:

Makes ghost radius centred on building being upgrading (if upgrading
building)
<img width="1920" height="1080" alt="Screenshot from 2026-06-01
15-45-37"
src="https://github.com/user-attachments/assets/9cf19e59-0e20-4b43-b65f-35eebb37fa8e"
/>
<img width="1920" height="1080" alt="Screenshot from 2026-06-01
15-45-24"
src="https://github.com/user-attachments/assets/1953238f-5156-4bf7-aa18-8278c27d1a68"
/>


## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory

## Please put your Discord username so you can be contacted if a bug or
regression is found:

tktk123456
---
 src/client/controllers/BuildPreviewController.ts | 12 ++++++++++++
 src/client/render/gl/passes/RangeCirclePass.ts   |  4 ++--
 src/client/render/types/Renderer.ts              |  2 ++
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/client/controllers/BuildPreviewController.ts b/src/client/controllers/BuildPreviewController.ts
index 3a9de6cdb..26a55b1b3 100644
--- a/src/client/controllers/BuildPreviewController.ts
+++ b/src/client/controllers/BuildPreviewController.ts
@@ -335,12 +335,24 @@ export class BuildPreviewController implements Controller {
         rangeRadius = this.game.config().defensePostRange();
         break;
     }
+    let radiusTileX = this.game.x(tileRef);
+    let radiusTileY = this.game.y(tileRef);
+    if (
+      rangeRadius > 0 &&
+      u.canUpgrade !== false &&
+      upgradeTargetTile !== null
+    ) {
+      radiusTileX = this.game.x(upgradeTargetTile);
+      radiusTileY = this.game.y(upgradeTargetTile);
+    }
 
     const cost = u.cost;
     return {
       ghostType: u.type,
       tileX: this.game.x(tileRef),
       tileY: this.game.y(tileRef),
+      radiusTileX,
+      radiusTileY,
       canBuild: u.canBuild !== false,
       canUpgrade: u.canUpgrade !== false,
       cost: Number(cost),
diff --git a/src/client/render/gl/passes/RangeCirclePass.ts b/src/client/render/gl/passes/RangeCirclePass.ts
index 8fbe41273..05351f95f 100644
--- a/src/client/render/gl/passes/RangeCirclePass.ts
+++ b/src/client/render/gl/passes/RangeCirclePass.ts
@@ -54,8 +54,8 @@ export class RangeCirclePass {
 
   updateGhostPreview(data: GhostPreviewData | null): void {
     if (data && data.rangeRadius > 0) {
-      this.centerX = data.tileX;
-      this.centerY = data.tileY;
+      this.centerX = data.radiusTileX;
+      this.centerY = data.radiusTileY;
       this.radius = data.rangeRadius;
       this.warning = data.rangeWarning;
     } else {
diff --git a/src/client/render/types/Renderer.ts b/src/client/render/types/Renderer.ts
index 652a5e338..355013ced 100644
--- a/src/client/render/types/Renderer.ts
+++ b/src/client/render/types/Renderer.ts
@@ -152,6 +152,8 @@ export interface GhostPreviewData {
   ghostType: string; // UnitType string ("City", "Port", etc.)
   tileX: number; // Hover tile X
   tileY: number; // Hover tile Y
+  radiusTileX: number;
+  radiusTileY: number;
   canBuild: boolean; // Valid placement?
   canUpgrade: boolean; // Upgrading existing structure?
   cost: number; // Gold cost