From 7286f77e83ebea2a1e52dec87e345f0545b47e9e Mon Sep 17 00:00:00 2001
From: "seer-by-sentry[bot]"
 <157164994+seer-by-sentry[bot]@users.noreply.github.com>
Date: Thu, 23 Apr 2026 20:39:54 +0000
Subject: [PATCH] bugfix(partitioning): Correct cell world coordinate
 calculation for overlap checks

---
 .../Source/GameLogic/Object/PartitionManager.cpp       | 10 ++++++++--
 .../Source/GameLogic/Object/PartitionManager.cpp       | 10 ++++++++--
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/Generals/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp b/Generals/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
index c954025becd..7f8f5f593cf 100644
--- a/Generals/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
+++ b/Generals/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
@@ -1887,13 +1887,19 @@ void PartitionData::doCircleFillPrecise(Real centerX, Real centerY, Real radius)
 	ThePartitionManager->worldToCell(centerX + radius, centerY + radius, &maxCellX, &maxCellY);
 
 	Real cellSize = ThePartitionManager->getCellSize();
+	Real halfCellSize = cellSize * 0.5f;
 
 	for (Int x = minCellX; x <= maxCellX; ++x)
 	{
 		for (Int y = minCellY; y <= maxCellY; ++y)
 		{
-			Real cellWorldX = x * cellSize;
-			Real cellWorldY = y * cellSize;
+			// getCellCenterPos returns the world-space center of the cell, accounting for
+			// m_worldExtents.lo offset. Subtracting halfCellSize gives the lower-left corner,
+			// which is what doesCircleOverlapCell expects.
+			Real cellWorldX, cellWorldY;
+			ThePartitionManager->getCellCenterPos(x, y, cellWorldX, cellWorldY);
+			cellWorldX -= halfCellSize;
+			cellWorldY -= halfCellSize;
 
 			if (doesCircleOverlapCell(centerX, centerY, radius, cellWorldX, cellWorldY, cellSize))
 			{
diff --git a/GeneralsMD/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp b/GeneralsMD/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
index b5e7985605e..ac51a43f5a3 100644
--- a/GeneralsMD/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
+++ b/GeneralsMD/Code/GameEngine/Source/GameLogic/Object/PartitionManager.cpp
@@ -1891,13 +1891,19 @@ void PartitionData::doCircleFillPrecise(Real centerX, Real centerY, Real radius)
 	ThePartitionManager->worldToCell(centerX + radius, centerY + radius, &maxCellX, &maxCellY);
 
 	Real cellSize = ThePartitionManager->getCellSize();
+	Real halfCellSize = cellSize * 0.5f;
 
 	for (Int x = minCellX; x <= maxCellX; ++x)
 	{
 		for (Int y = minCellY; y <= maxCellY; ++y)
 		{
-			Real cellWorldX = x * cellSize;
-			Real cellWorldY = y * cellSize;
+			// getCellCenterPos returns the world-space center of the cell, accounting for
+			// m_worldExtents.lo offset. Subtracting halfCellSize gives the lower-left corner,
+			// which is what doesCircleOverlapCell expects.
+			Real cellWorldX, cellWorldY;
+			ThePartitionManager->getCellCenterPos(x, y, cellWorldX, cellWorldY);
+			cellWorldX -= halfCellSize;
+			cellWorldY -= halfCellSize;
 
 			if (doesCircleOverlapCell(centerX, centerY, radius, cellWorldX, cellWorldY, cellSize))
 			{