From 7916dfb61d96988689b134cdd303edce879c6ca3 Mon Sep 17 00:00:00 2001
From: Stuart Buchanan <stuart_d_buchanan@yahoo.co.uk>
Date: Wed, 20 Oct 2021 23:37:59 +0100
Subject: [PATCH] WS30 Move VPB tile loading to the tile manager

Previously VPB tiles were loaded by the STG file handler.
Now they are loaded directly by the tile manager, allowing
better management of tile loading.
---
 simgear/bucket/newbucket.hxx           | 14 ++++++++++++++
 simgear/scene/tgdb/ReaderWriterSTG.cxx | 22 ----------------------
 simgear/scene/tgdb/ReaderWriterSTG.hxx |  4 ----
 3 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/simgear/bucket/newbucket.hxx b/simgear/bucket/newbucket.hxx
index 92b0297d..6243b146 100644
--- a/simgear/bucket/newbucket.hxx
+++ b/simgear/bucket/newbucket.hxx
@@ -182,6 +182,20 @@ public:
 	    return ((lon + 180) << 14) + ((lat + 90) << 6) + static_cast<unsigned char>(y << 3) + x;
     }
 
+    /**
+     * Generate a tile index for this bucket shared with all other buckets with the same lat/lon.
+     * Used as an index for VPB tiles, which are 1x1 in size.
+     *
+     * The index is constructed as follows:
+     * 
+     * 9 bits - to represent 360 degrees of longitude (-180 to 179)
+     * 8 bits - to represent 180 degrees of latitude (-90 to 89)
+     * @return tile index
+     */
+    inline long int gen_vpb_index() const {
+	    return ((lon + 180) << 8) + (lat + 90);
+    }
+
     /**
      * Generate the unique scenery tile index for this bucket in ascii
      * string form.
diff --git a/simgear/scene/tgdb/ReaderWriterSTG.cxx b/simgear/scene/tgdb/ReaderWriterSTG.cxx
index 75ca6a30..3bab4097 100644
--- a/simgear/scene/tgdb/ReaderWriterSTG.cxx
+++ b/simgear/scene/tgdb/ReaderWriterSTG.cxx
@@ -765,7 +765,6 @@ struct ReaderWriterSTG::_ModelBin {
     osg::Node* load(const SGBucket& bucket, const osgDB::Options* opt)
     {
         osg::ref_ptr<SGReaderWriterOptions> options;
-        osg::ref_ptr<osg::Node> vpb_node;
         options = SGReaderWriterOptions::copyOrCreate(opt);
         float pagedLODExpiry = atoi(options->getPluginStringData("SimGear::PAGED_LOD_EXPIRY").c_str());
 
@@ -819,27 +818,6 @@ struct ReaderWriterSTG::_ModelBin {
                 VPBTechnique::addCoastlineList(bucket, coastFeatures);
             }
 
-            std::string filename = "vpb/" + bucket.gen_vpb_base() + ".osgb";
-
-            // Lock for this scope
-            {
-                const std::lock_guard<std::mutex> lock(ReaderWriterSTG::_tileMapMutex); 
-
-                if (_tileMap.count(filename) == 0) {
-                    vpb_node = osgDB::readRefNodeFile(filename, options);
-                    if (!vpb_node.valid()) {
-                        SG_LOG(SG_TERRAIN, SG_WARN, "Failure to load: " <<filename);
-                    }
-                    else {
-                        terrainGroup->addChild(vpb_node);
-                        _tileMap[filename] = vpb_node;
-                        SG_LOG(SG_TERRAIN, SG_INFO, "Loading: " << filename);
-                    }
-                } else {
-                    vpb_node = _tileMap[filename];
-                }
-            }
-
             // OBJECTs include airports
             for (auto stgObject : _objectList) {
                 osg::ref_ptr<osg::Node> node;
diff --git a/simgear/scene/tgdb/ReaderWriterSTG.hxx b/simgear/scene/tgdb/ReaderWriterSTG.hxx
index 9fa1354d..bbf3ebbb 100644
--- a/simgear/scene/tgdb/ReaderWriterSTG.hxx
+++ b/simgear/scene/tgdb/ReaderWriterSTG.hxx
@@ -50,10 +50,6 @@ public:
     static void removeSTGObjectHandler(const std::string &token, STGObjectCallback callback);
 private:
     struct _ModelBin;
-
-    inline static std::map<std::string, osg::ref_ptr<osg::Node> > _tileMap;
-    inline static std::mutex _tileMapMutex;  // protects the _lineFeatureLists;
-
 };
 
 }