Fix render distance issues (#5381)

* Potentially fix render distance issues

* AGGRESSIVE fix render distance issues

---------

Co-authored-by: Camotoy <[email protected]>

Author: onebeastchris

core/src/main/java/org/geysermc/geyser/session/GeyserSession.java

@@ -341,7 +341,6 @@ public class GeyserSession implements GeyserConnection, GeyserCommandSource {
 
     @Setter
     private Vector2i lastChunkPosition = null;
-    @Setter
     private int clientRenderDistance = -1;
     private int serverRenderDistance = -1;
 
@@ -1453,11 +1452,31 @@ public void sendCommand(String command) {
         sendDownstreamGamePacket(new ServerboundChatCommandSignedPacket(command, Instant.now().toEpochMilli(), 0L, Collections.emptyList(), 0, new BitSet()));
     }
 
+    public void setClientRenderDistance(int clientRenderDistance) {
+        boolean oldSquareToCircle = this.clientRenderDistance < this.serverRenderDistance;
+        this.clientRenderDistance = clientRenderDistance;
+        boolean newSquareToCircle = this.clientRenderDistance < this.serverRenderDistance;
+
+        if (this.serverRenderDistance != -1 && oldSquareToCircle != newSquareToCircle) {
+            recalculateBedrockRenderDistance();
+        }
+    }
+
     public void setServerRenderDistance(int renderDistance) {
         // Ensure render distance is not above 96 as sending a larger value at any point crashes mobile clients and 96 is the max of any bedrock platform
         renderDistance = Math.min(renderDistance, 96);
         this.serverRenderDistance = renderDistance;
 
+        recalculateBedrockRenderDistance();
+    }
+
+    /**
+     * Ensures that the ChunkRadiusUpdatedPacket uses the correct render distance for whatever the client distance is set as.
+     * If the server render distance is larger than the client's, then account for this and add some extra padding.
+     * We don't want to apply this for every render distance, if at all possible, because
+     */
+    private void recalculateBedrockRenderDistance() {
+        int renderDistance = ChunkUtils.squareToCircle(this.serverRenderDistance);
         ChunkRadiusUpdatedPacket chunkRadiusUpdatedPacket = new ChunkRadiusUpdatedPacket();
         chunkRadiusUpdatedPacket.setRadius(renderDistance);
         upstream.sendPacket(chunkRadiusUpdatedPacket);

core/src/main/java/org/geysermc/geyser/util/ChunkUtils.java

@@ -99,13 +99,20 @@ public static void updateChunkPosition(GeyserSession session, Vector3i position)
             chunkPublisherUpdatePacket.setPosition(position);
             // Mitigates chunks not loading on 1.17.1 Paper and 1.19.3 Fabric. As of Bedrock 1.19.60.
             // https://github.com/GeyserMC/Geyser/issues/3490
-            chunkPublisherUpdatePacket.setRadius(GenericMath.ceil((session.getServerRenderDistance() + 1) * MathUtils.SQRT_OF_TWO) << 4);
+            chunkPublisherUpdatePacket.setRadius(squareToCircle(session.getServerRenderDistance()) << 4);
             session.sendUpstreamPacket(chunkPublisherUpdatePacket);
 
             session.setLastChunkPosition(newChunkPos);
         }
     }
 
+    /**
+     * Converts a Java render distance number to the equivalent in Bedrock.
+     */
+    public static int squareToCircle(int renderDistance) {
+        return GenericMath.ceil((renderDistance + 1) * MathUtils.SQRT_OF_TWO);
+    }
+
     /**
      * Sends a block update to the Bedrock client. If the platform is not Spigot, this also
      * adds that block to the cache.