From b10ddf976217c511a1f4dbeb6a0dd1b35dd31d03 Mon Sep 17 00:00:00 2001
From: "s0wlz (Matthias Puchstein)" <matthias@puchstein.lu>
Date: Wed, 11 Feb 2026 00:35:39 +0100
Subject: [PATCH] Prioritize boundary inflow over boundary outflow on ghost
 cells

---
 .../Networking/Server/SweServerRuntime.cs     | 25 ++++++++++++++++---
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/Assets/Scripts/Networking/Server/SweServerRuntime.cs b/Assets/Scripts/Networking/Server/SweServerRuntime.cs
index 8db30f212..5eb3fa065 100644
--- a/Assets/Scripts/Networking/Server/SweServerRuntime.cs
+++ b/Assets/Scripts/Networking/Server/SweServerRuntime.cs
@@ -753,7 +753,9 @@ namespace FloodSWE.Networking
             var ghostIndices = new List<int>(128);
             var ghostLevels = new List<float>(128);
             var ghostVelocities = new List<Vector2>(128);
+            var ghostInflowCells = new HashSet<int>();
             var ghostOutflowCells = new HashSet<int>();
+            var suppressedOutflowCells = new HashSet<int>();
             var boundarySinkIdsWithGhostOutflow = new HashSet<int>();
 
             foreach (var pair in activeBoundaryInflowGhostCells)
@@ -778,9 +780,16 @@ namespace FloodSWE.Networking
                 Vector2 velocity = new Vector2(profile.velocityUMps, profile.velocityVMps);
                 for (int i = 0; i < cells.Length; i++)
                 {
-                    ghostIndices.Add(cells[i]);
+                    int idx = cells[i];
+                    if (idx < 0)
+                    {
+                        continue;
+                    }
+
+                    ghostIndices.Add(idx);
                     ghostLevels.Add(level);
                     ghostVelocities.Add(velocity);
+                    ghostInflowCells.Add(idx);
                 }
             }
 
@@ -817,10 +826,18 @@ namespace FloodSWE.Networking
                 for (int i = 0; i < cells.Length; i++)
                 {
                     int idx = cells[i];
-                    if (idx >= 0)
+                    if (idx < 0)
                     {
-                        ghostOutflowCells.Add(idx);
+                        continue;
                     }
+
+                    if (ghostInflowCells.Contains(idx))
+                    {
+                        suppressedOutflowCells.Add(idx);
+                        continue;
+                    }
+
+                    ghostOutflowCells.Add(idx);
                 }
             }
 
@@ -988,7 +1005,7 @@ namespace FloodSWE.Networking
             if (verboseDiagnostics)
             {
                 Debug.Log(
-                    $"SweServerRuntime: forcing applied status={lastForcingStatus} ghost={ghostIndices.Count} depth={forcedDepthCells} freeOutflow={ghostOutflowCells.Count}");
+                    $"SweServerRuntime: forcing applied status={lastForcingStatus} ghost={ghostIndices.Count} depth={forcedDepthCells} freeOutflow={ghostOutflowCells.Count} suppressedOutflowByInflow={suppressedOutflowCells.Count}");
             }
         }