From cd5a3ce52b91cca240cf87b2ea68c8212f759382 Mon Sep 17 00:00:00 2001
From: James Seibel <jeseibel@gondtc.com>
Date: Sat, 14 Mar 2026 10:18:40 -0500
Subject: [PATCH] Try fix concurrency issue with render closing

---
 .../core/render/QuadTree/LodQuadTree.java     | 28 +++++++++++++------
 .../core/util/objects/quadTree/QuadNode.java  | 11 ++++++++
 2 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/core/src/main/java/com/seibel/distanthorizons/core/render/QuadTree/LodQuadTree.java b/core/src/main/java/com/seibel/distanthorizons/core/render/QuadTree/LodQuadTree.java
index 663df4b57..393e156a7 100644
--- a/core/src/main/java/com/seibel/distanthorizons/core/render/QuadTree/LodQuadTree.java
+++ b/core/src/main/java/com/seibel/distanthorizons/core/render/QuadTree/LodQuadTree.java
@@ -34,6 +34,7 @@ import com.seibel.distanthorizons.core.logging.DhLoggerBuilder;
 import com.seibel.distanthorizons.core.pos.blockPos.DhBlockPos2D;
 import com.seibel.distanthorizons.core.pos.DhSectionPos;
 import com.seibel.distanthorizons.core.render.RenderBufferHandler;
+import com.seibel.distanthorizons.core.render.RenderThreadTaskHandler;
 import com.seibel.distanthorizons.core.render.renderer.AbstractDebugWireframeRenderer;
 import com.seibel.distanthorizons.core.render.renderer.BeaconRenderHandler;
 import com.seibel.distanthorizons.core.render.renderer.IDebugRenderable;
@@ -371,16 +372,27 @@ public class LodQuadTree extends QuadTree<LodRenderSection> implements IDebugRen
 		
 		for (QuadNode<LodRenderSection> node : this.tickNodeHolder.getEnableDeleteChildrenNodes())
 		{
-			if (node == null || node.value == null) { continue; }
-			
-			node.deleteAllChildren((childRenderSection) ->
+			if (node == null
+				|| node.value == null
+				// only clear the children if there are children to clear
+				|| node.getDirectChildCount() == 0) 
 			{
-				if (childRenderSection != null)
+				continue; 
+			}
+			
+			// run this on the render thread to hopefully prevent
+			// closing render data while rendering is happening
+			RenderThreadTaskHandler.INSTANCE.queueRunningOnRenderThread("LodQuadTree delayed child cleanup", () -> 
+			{
+				node.deleteAllChildren((childRenderSection) ->
 				{
-					childRenderSection.setRenderingEnabled(false);
-					childRenderSection.tryDisableBeacons();
-					childRenderSection.close();
-				}
+					if (childRenderSection != null)
+					{
+						childRenderSection.setRenderingEnabled(false);
+						childRenderSection.tryDisableBeacons();
+						childRenderSection.close();
+					}
+				});
 			});
 		}
 		
diff --git a/core/src/main/java/com/seibel/distanthorizons/core/util/objects/quadTree/QuadNode.java b/core/src/main/java/com/seibel/distanthorizons/core/util/objects/quadTree/QuadNode.java
index dccc144eb..88382be63 100644
--- a/core/src/main/java/com/seibel/distanthorizons/core/util/objects/quadTree/QuadNode.java
+++ b/core/src/main/java/com/seibel/distanthorizons/core/util/objects/quadTree/QuadNode.java
@@ -86,6 +86,17 @@ public class QuadNode<T>
 	
 	
 	
+	/** @return the number of non-null direct child nodes */
+	public int getDirectChildCount()
+	{
+		int count = 0;
+		if (this.nwChild != null) { count++; }
+		if (this.neChild != null) { count++; }
+		if (this.swChild != null) { count++; }
+		if (this.seChild != null) { count++; }
+		return count;
+	}
+	
 	/**
 	 * Use {@link QuadNode#getNonNullChildCount()} if you want the number of non-null child values.
 	 *