TREE_LIST STG verb

Add a TREE_LIST STG analogous to the existing BUILDING_LIST verb

  TREE_LIST <filename> <material name> <lon> <lat> <elev>

where <filename> is a file containing a set of trees to generate
using the defined <material name> at the given location.

The referenced <filename> contains lines of the form

X Y Z A B C

Where:
- X,Y,Z are the cartesian coordinates of the tree. +X is East, +Y is North
- A,B,C is optional and represents the normal of the underlying terrain.  Used for shadows.  Defaults to (0,0,1)

simgear/scene/tgdb/ReaderWriterSTG.cxx

@@ -52,6 +52,7 @@
 #include <simgear/scene/tgdb/obj.hxx>
 #include <simgear/scene/material/matlib.hxx>
 #include <simgear/scene/tgdb/SGBuildingBin.hxx>
+#include <simgear/scene/tgdb/TreeBin.hxx>
 
 #include <simgear/scene/util/SGSceneFeatures.hxx>
 
@@ -64,6 +65,7 @@
 #define RAILWAY_ROUGH "OBJECT_RAILWAY_ROUGH"
 #define RAILWAY_DETAILED "OBJECT_RAILWAY_DETAILED"
 #define BUILDING_LIST "BUILDING_LIST"
+#define TREE_LIST "TREE_LIST"
 
 namespace simgear {
 
@@ -139,6 +141,13 @@ struct ReaderWriterSTG::_ModelBin {
       std::string _material_name;
       double _lon, _lat, _elev;
     };
+    struct _TreeList {
+      _TreeList() : _lon(0), _lat(0), _elev(0) { }
+      std::string _filename;
+      std::string _material_name;
+      double _lon, _lat, _elev;
+    };
+
 
     class DelayLoadReadFileCallback : public OptionsReadFileCallback {
 
@@ -258,6 +267,45 @@ struct ReaderWriterSTG::_ModelBin {
                 }
             }
 
+            if (!_treeList.empty()) {
+                SGMaterialLibPtr matlib = _options->getMaterialLib();
+
+                if (!matlib) {
+                    SG_LOG( SG_TERRAIN, SG_ALERT, "Unable to get materials definition for buildings");
+                } else {
+                    for (const auto& b : _treeList) {
+                        // Build buildings for each list of buildings
+                        SGGeod geodPos = SGGeod::fromDegM(b._lon, b._lat, 0.0);
+                        SGSharedPtr<SGMaterial> mat = matlib->find(b._material_name, geodPos);
+
+                        // trying to avoid crash on null material, see:
+                        // https://sentry.io/organizations/flightgear/issues/1867075869
+                        if (!mat) {
+                            SG_LOG(SG_TERRAIN, SG_ALERT, "Tree list specifies unknown material: " << b._filename << " " << b._material_name);
+                            continue;
+                        }
+
+                        const auto path = SGPath(b._filename);
+                        TreeBin* treeBin = new TreeBin(path, mat);
+
+                        SGTreeBinList treeList;
+                        treeList.push_back(treeBin);
+                        SG_LOG(SG_TERRAIN, SG_ALERT, "Making trees " << b._material_name);
+
+                        osg::MatrixTransform* matrixTransform;
+                        matrixTransform = new osg::MatrixTransform(makeZUpFrame(SGGeod::fromDegM(b._lon, b._lat, b._elev)));
+                        matrixTransform->setName("rotateTrees");
+                        matrixTransform->setDataVariance(osg::Object::STATIC);
+                        matrixTransform->addChild(createForest(treeList, osg::Matrix::identity(), _options));
+                        group->addChild(matrixTransform);
+
+                        std::for_each(treeList.begin(), treeList.end(), [](TreeBin* bb) {
+                            delete bb;
+                        });
+                    }
+                }
+            }
+
             return group.release();
         }
 
@@ -265,6 +313,7 @@ struct ReaderWriterSTG::_ModelBin {
         std::list<_ObjectStatic> _objectStaticList;
         std::list<_Sign> _signList;
         std::list<_BuildingList> _buildingList;
+        std::list<_TreeList> _treeList;
 
         /// The original options to use for this bunch of models
         osg::ref_ptr<SGReaderWriterOptions> _options;
@@ -554,7 +603,12 @@ struct ReaderWriterSTG::_ModelBin {
                   in >> buildinglist._material_name >> buildinglist._lon >> buildinglist._lat >> buildinglist._elev;
                   checkInsideBucket(absoluteFileName, buildinglist._lon, buildinglist._lat);
                   _buildingListList.push_back(buildinglist);
-                  //SG_LOG(SG_TERRAIN, SG_ALERT, "Building list: " << buildinglist._filename << " " << buildinglist._material_name << " " << buildinglist._lon << " " << buildinglist._lat);
+                } else if (token == TREE_LIST) {
+                  _TreeList treelist;
+                  treelist._filename = path.utf8Str();
+                  in >> treelist._material_name >> treelist._lon >> treelist._lat >> treelist._elev;
+                  checkInsideBucket(absoluteFileName, treelist._lon, treelist._lat);
+                  _treeListList.push_back(treelist);
                 } else {
                     // Check registered callback for token. Keep lock until callback completed to make sure it will not be
                     // executed after a thread successfully executed removeSTGObjectHandler()
@@ -640,7 +694,7 @@ struct ReaderWriterSTG::_ModelBin {
             i->_elev += elevation(*terrainGroup, SGGeod::fromDeg(i->_lon, i->_lat));
         }
 
-        if (_objectStaticList.empty() && _signList.empty() && (_buildingListList.size() == 0)) {
+        if (_objectStaticList.empty() && _signList.empty() && (_buildingListList.size() == 0) && (_treeListList.size() == 0)) {
             // The simple case, just return the terrain group
             return terrainGroup.release();
         } else {
@@ -656,6 +710,7 @@ struct ReaderWriterSTG::_ModelBin {
             osg::ref_ptr<DelayLoadReadFileCallback> readFileCallback = new DelayLoadReadFileCallback;
             readFileCallback->_objectStaticList = _objectStaticList;
             readFileCallback->_buildingList = _buildingListList;
+            readFileCallback->_treeList = _treeListList;
             readFileCallback->_signList = _signList;
             readFileCallback->_options = options;
             readFileCallback->_bucket = bucket;
@@ -683,6 +738,7 @@ struct ReaderWriterSTG::_ModelBin {
     std::list<_ObjectStatic> _objectStaticList;
     std::list<_Sign> _signList;
     std::list<_BuildingList> _buildingListList;
+    std::list<_TreeList> _treeListList;
 };
 
 ReaderWriterSTG::ReaderWriterSTG()

simgear/scene/tgdb/TreeBin.cxx

@@ -39,6 +39,7 @@
 #include <osgDB/FileUtils>
 
 #include <simgear/debug/logstream.hxx>
+#include <simgear/io/iostreams/sgstream.hxx>
 #include <simgear/math/sg_random.h>
 #include <simgear/misc/sg_path.hxx>
 #include <simgear/scene/material/Effect.hxx>
@@ -442,5 +443,70 @@ osg::Group* createForest(SGTreeBinList& forestList, const osg::Matrix& transform
     return mt;
 }
 
+TreeBin::TreeBin(const SGMaterial *mat)
+{
+    texture_varieties = mat->get_tree_varieties();
+    range = mat->get_tree_range();
+    height = mat->get_tree_height();
+    width = mat->get_tree_width();
+    texture = mat->get_tree_texture();
+    teffect = mat->get_tree_effect();
+};
+
+
+TreeBin::TreeBin(const SGPath& absoluteFileName, const SGMaterial *mat) : 
+TreeBin(mat)
+{
+    if (!absoluteFileName.exists()) {
+        SG_LOG(SG_TERRAIN, SG_ALERT, "Tree list file " << absoluteFileName << " does not exist.");
+        return;
+    }
+
+    sg_gzifstream stream(absoluteFileName);
+    if (!stream.is_open()) {
+        SG_LOG(SG_TERRAIN, SG_ALERT, "Unable to open " << absoluteFileName);
+        return;
+    }
+
+    while (!stream.eof()) {
+        // read a line.  Each line defines a single tree position, and may have
+        // a comment, starting with #
+        std::string line;
+        std::getline(stream, line);
+
+        // strip comments
+        std::string::size_type hash_pos = line.find('#');
+        if (hash_pos != std::string::npos)
+            line.resize(hash_pos);
+
+        // and process further
+        std::stringstream in(line);
+
+        // Line format is X Y Z A B C
+        // where:
+        // X,Y,Z are the cartesian coordinates of the center tree
+        // A,B,C is the normal of the underlying terrain, defaulting to 0,0,1
+        float x = 0.0f, y = 0.0f, z = 0.0f, a = 0.0f, b = 0.0f, c = 1.0f;
+        in >> x >> y >> z;
+
+        if (in.bad() || in.fail()) {
+            SG_LOG(SG_TERRAIN, SG_WARN, "Error parsing tree entry in: " << absoluteFileName << " line: \"" << line << "\"");
+            continue;
+        }
+
+        // these might fail, so check them after we look at failbit
+        in >> a >> b >> c;
+
+        SGVec3f loc = SGVec3f(x,y,z);
+        SGVec3f norm = SGVec3f(a,b,c);
+
+        SG_LOG(SG_TERRAIN, SG_ALERT, "Adding tree " << x << " " << y << " " << z);
+
+        insert(Tree(loc, norm));
+    }
+
+    stream.close();
+};
+
 
 }

simgear/scene/tgdb/TreeBin.hxx

@@ -35,6 +35,10 @@ namespace simgear
 {
 class TreeBin {
 public:
+    TreeBin() = default;
+    TreeBin(const SGMaterial *mat);
+    TreeBin(const SGPath& absoluteFileName, const SGMaterial *mat);
+
     ~TreeBin() = default;
 
     struct Tree {