From 2c266d2495d4e70f23e59572d5baefcc635e3286 Mon Sep 17 00:00:00 2001
From: James Seibel <jeseibel@gondtc.com>
Date: Sun, 19 Apr 2026 21:48:26 -0500
Subject: [PATCH] Fix LODs loading outside render distance

Fixes !1233
---
 .../core/render/QuadTree/LodQuadTree.java     | 25 +++++++-
 .../core/util/objects/quadTree/QuadTree.java  | 63 +++++++++++++++----
 2 files changed, 74 insertions(+), 14 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 1867601ea..4cf96dc4f 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
@@ -245,7 +245,7 @@ public class LodQuadTree extends QuadTree<LodRenderSection> implements IDebugRen
 		//===================//
 		//region
 		
-		// remove out of bounds sections
+		// remove out of bound sections
 		this.setCenterBlockPos(playerPos, (renderSection) ->
 		{
 			if (renderSection != null)
@@ -497,7 +497,7 @@ public class LodQuadTree extends QuadTree<LodRenderSection> implements IDebugRen
 		
 		// create the node
 		if (quadNode == null)
-		{   
+		{
 			rootNode.setValue(sectionPos, new LodRenderSection(sectionPos, this, this.level, this.fullDataSourceProvider));
 			quadNode = rootNode.getNode(sectionPos);
 		}
@@ -506,6 +506,16 @@ public class LodQuadTree extends QuadTree<LodRenderSection> implements IDebugRen
 			LodUtil.assertNotReach("Unable to add node with pos ["+DhSectionPos.toString(sectionPos)+"] to tree root ["+rootNode+"].");
 		}
 		
+		
+		// Skip sections that are out-of-bounds.
+		// If not done some sections will appear and/or generate 
+		// outside the desired render distance
+		if (!this.isSectionPosInBounds(quadNode.sectionPos))
+		{
+			return;
+		}
+		
+		
 		// make sure the render section is created (shouldn't be necessary, but just in case)
 		LodRenderSection renderSection = quadNode.value;
 		if (renderSection == null)
@@ -1121,6 +1131,17 @@ public class LodQuadTree extends QuadTree<LodRenderSection> implements IDebugRen
 	{
 		this.populateListWithEnabledRenderSections(this.debugNodeList);
 		
+		//// can be uncommented for debugging/finding a specific position
+		//debugRenderer.makeParticle(
+		//	new AbstractDebugWireframeRenderer.BoxParticle(
+		//		new AbstractDebugWireframeRenderer.Box(
+		//			DhSectionPos.encode((byte)7, 3,-1)
+		//			, -64, 400,
+		//			0.1f, 
+		//			Color.YELLOW),
+		//		0.5, 0f
+		//	));
+		
 		for (int i = 0; i < this.debugNodeList.size(); i++)
 		{
 			LodRenderSection renderSection = this.debugNodeList.get(i);
diff --git a/core/src/main/java/com/seibel/distanthorizons/core/util/objects/quadTree/QuadTree.java b/core/src/main/java/com/seibel/distanthorizons/core/util/objects/quadTree/QuadTree.java
index e6ec31034..67f6614cc 100644
--- a/core/src/main/java/com/seibel/distanthorizons/core/util/objects/quadTree/QuadTree.java
+++ b/core/src/main/java/com/seibel/distanthorizons/core/util/objects/quadTree/QuadTree.java
@@ -359,19 +359,11 @@ public class QuadTree<T>
 	{
 		this.centerBlockPos = newCenterPos;
 		
-		MovableGridRingList.Pos2D expectedCenterPos = new MovableGridRingList.Pos2D(
-				BitShiftUtil.divideByPowerOfTwo(this.centerBlockPos.x, this.treeRootDetailLevel),
-				BitShiftUtil.divideByPowerOfTwo(this.centerBlockPos.z, this.treeRootDetailLevel));
+		int newCenterPosX = BitShiftUtil.divideByPowerOfTwo(this.centerBlockPos.x, this.treeRootDetailLevel);
+		int newCenterPosZ = BitShiftUtil.divideByPowerOfTwo(this.centerBlockPos.z, this.treeRootDetailLevel);
 		
-		if (this.topRingList.getCenter().equals(expectedCenterPos))
-		{
-			// tree doesn't need to be moved
-			return;
-		}
-		
-		
-		// remove out of bounds root nodes
-		this.topRingList.moveTo(expectedCenterPos.getX(), expectedCenterPos.getY(), (quadNode) ->
+		// remove out of bound root nodes
+		this.topRingList.moveTo(newCenterPosX, newCenterPosZ, (quadNode) ->
 		{
 			if (quadNode != null)
 			{
@@ -383,6 +375,53 @@ public class QuadTree<T>
 				}
 			}
 		});
+		
+		// remove out of bound child nodes
+		this.topRingList.forEach((rootNode) ->
+		{
+			this.recursivelyClearOutOfBoundNodes(rootNode, removedItemConsumer);
+		});
+		
+	}
+	private void recursivelyClearOutOfBoundNodes(@Nullable QuadNode<T> quadNode, @Nullable Consumer<? super T> removedItemConsumer)
+	{
+		// nodes shouldn't be null, but just in case
+		if (quadNode == null)
+		{
+			return;
+		}
+		
+		// go over each child node
+		for (int i = 0; i < 4; i++)
+		{
+			QuadNode<T> childNode = quadNode.getChildByIndex(i);
+			if (childNode == null
+				|| childNode.value == null)
+			{
+				// no need to go any deeper if this node is already empty
+				continue;
+			}
+			
+			// clear nodes from the bottom up
+			this.recursivelyClearOutOfBoundNodes(childNode, removedItemConsumer);
+			
+			// clear this node if out of bounds
+			if (!this.isSectionPosInBounds(childNode.sectionPos))
+			{
+				T oldValue = childNode.value;
+				
+				// We don't remove the node until the root is removed since there isn't an
+				// easy way to do so.
+				// However, from outside the tree a null value is equivalent to the node 
+				// not existing, so it should work fine.
+				childNode.value = null;
+				
+				if (removedItemConsumer != null)
+				{
+					removedItemConsumer.accept(oldValue);
+				}
+			}
+		}
 	}
 	
 	public final DhBlockPos2D getCenterBlockPos() { return this.centerBlockPos; }