From 56996cc01ae82dbdb40b1e720b91092d93247e25 Mon Sep 17 00:00:00 2001
From: Stuart Buchanan <stuart_d_buchanan@yahoo.co.uk>
Date: Thu, 1 Dec 2022 16:43:23 +0000
Subject: [PATCH] WS30 - Clear WS30 data on tile unload

Previously WS30 data from STG files - in particular road/rail/river
data - was kept permanently.

This change unloads it with the STG-level tile.  This is the right
level to do so, as it will be reloaded from tile when the STG file
is loaded again.
---
 src/Scenery/tilemgr.cxx | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Scenery/tilemgr.cxx b/src/Scenery/tilemgr.cxx
index 7a94bb3f7..97637b277 100644
--- a/src/Scenery/tilemgr.cxx
+++ b/src/Scenery/tilemgr.cxx
@@ -36,6 +36,7 @@
 #include <simgear/structure/exception.hxx>
 #include <simgear/scene/model/modellib.hxx>
 #include <simgear/scene/util/SGReaderWriterOptions.hxx>
+#include <simgear/scene/tgdb/VPBTechnique.hxx>
 #include <simgear/scene/tsync/terrasync.hxx>
 #include <simgear/misc/strutils.hxx>
 #include <simgear/scene/material/matlib.hxx>
@@ -497,6 +498,11 @@ void FGTileMgr::update_queues(bool& isDownloadingScenery)
 
             tile_cache.clear_entry(drop_index);
 
+            if (_use_vpb) {
+                // Clear out any VPB data - e.g. roads
+                simgear::VPBTechnique::unloadFeatures(old->get_tile_bucket());
+            }
+
             osg::ref_ptr<osg::Object> subgraph = old->getNode();
             old->removeFromSceneGraph();
             delete old;