WS30: Landclass to material mapping

Using indirection in materials.xml

<landclass-mapping>
  <map>
    <description>111 - Continuous urban fabric</description>
    <landclass>1</landclass>
    <material-name>Urban</material-name>
  </map>
</landclass-mapping>

simgear/scene/material/matlib.cxx

@@ -51,7 +51,6 @@
 
 using std::string;
 
-
 class SGMaterialLib::MatLibPrivate
 {
 public:
@@ -127,8 +126,7 @@ bool SGMaterialLib::load( const SGPath &fg_root, const SGPath& mpath,
 		}
 
 		// Now build all the materials for this set of areas and conditions
-
-                const std::string region = node->getStringValue("name");
+        const std::string region = node->getStringValue("name");
 		const simgear::PropertyList materials = node->getChildren("material");
 		simgear::PropertyList::const_iterator materials_iter = materials.begin();
 		for (; materials_iter != materials.end(); materials_iter++) {
@@ -148,6 +146,23 @@ bool SGMaterialLib::load( const SGPath &fg_root, const SGPath& mpath,
 		}
     }
 
+    simgear::PropertyList landclasses = materialblocks.getNode("landclass-mapping", true)->getChildren("map");
+    simgear::PropertyList::const_iterator lc_iter = landclasses.begin();
+
+    for (; lc_iter != landclasses.end(); lc_iter++) {
+    	SGPropertyNode_ptr node = lc_iter->get();
+		int lc = node->getIntValue("landclass");
+		const std::string mat = node->getStringValue("material-name");
+        
+        // Verify that the landclass mapping exists before creating the mapping
+        const_material_map_iterator it = matlib.find( mat );
+        if ( it == end() ) {
+            SG_LOG(SG_TERRAIN, SG_ALERT, "Unable to find material " << mat << " for landclass " << lc);
+        } else {
+            landclasslib[lc] = mat;
+        }
+    }
+
     return true;
 }
 
@@ -174,6 +189,16 @@ SGMaterial *SGMaterialLib::find( const string& material, const SGVec2f center )
     return NULL;
 }
 
+SGMaterial *SGMaterialLib::find( int lc, const SGVec2f center ) const
+{
+    const_landclass_map_iterator it = landclasslib.find( lc );
+    if (it != landclasslib.end()) {
+        return find(it->second, center);
+    } else {
+        return NULL;
+    }
+}
+
 // find a material record by material name and tile center
 SGMaterial *SGMaterialLib::find( const string& material, const SGGeod& center ) const
 {
@@ -181,6 +206,17 @@ SGMaterial *SGMaterialLib::find( const string& material, const SGGeod& center )
 	return find(material, c);
 }
 
+// find a material record by material name and tile center
+SGMaterial *SGMaterialLib::find( int lc, const SGGeod& center ) const
+{
+    const_landclass_map_iterator it = landclasslib.find( lc );
+    if (it != landclasslib.end()) {
+        return find(it->second, center);
+    } else {
+        return NULL;
+    }
+}
+
 SGMaterialCache *SGMaterialLib::generateMatCache(SGVec2f center)
 {
 	SGMaterialCache* newCache = new SGMaterialCache();
@@ -189,6 +225,12 @@ SGMaterialCache *SGMaterialLib::generateMatCache(SGVec2f center)
         newCache->insert(it->first, find(it->first, center));
     }
 
+    // Collapse down the mapping from landclasses to materials.
+    const_landclass_map_iterator lc_iter = landclasslib.begin();
+    for (; lc_iter != landclasslib.end(); ++lc_iter) {
+        newCache->insert(lc_iter->first, find(lc_iter->second, center));
+    }
+
     return newCache;
 }
 
@@ -232,6 +274,11 @@ void SGMaterialCache::insert(const std::string& name, SGSharedPtr<SGMaterial> ma
 	cache[name] = material;    
 }
 
+void SGMaterialCache::insert(int lc, SGSharedPtr<SGMaterial> material) {
+	cache[getNameFromLandclass(lc)] = material;
+}
+
+
 // Search of the material cache
 SGMaterial *SGMaterialCache::find(const string& material) const
 {
@@ -242,6 +289,12 @@ SGMaterial *SGMaterialCache::find(const string& material) const
     return it->second;
 }
 
+// Search of the material cache for a material code as an integer (e.g. from a VPB landclass texture).
+SGMaterial *SGMaterialCache::find(int lc) const
+{
+    return find(getNameFromLandclass(lc));
+}
+
 // Destructor
 SGMaterialCache::~SGMaterialCache ( void ) {
     SG_LOG( SG_TERRAIN, SG_DEBUG, "SGMaterialCache::~SGMaterialCache() size=" << cache.size());

simgear/scene/material/matlib.hxx

@@ -50,15 +50,21 @@ private:
     typedef std::map < std::string, SGSharedPtr<SGMaterial> > material_cache;
     material_cache cache;
 
+    const std::string getNameFromLandclass(int lc) const {
+        return std::string("WS30_").append(std::to_string(lc));
+    }
+
 public:
     // Constructor
     SGMaterialCache ( void );
 
     // Insertion
     void insert( const std::string& name, SGSharedPtr<SGMaterial> material );
+    void insert( int lc, SGSharedPtr<SGMaterial> material );
 
     // Lookup
     SGMaterial *find( const std::string& material ) const;
+    SGMaterial *find( int material ) const;
 
     // Destructor
     ~SGMaterialCache ( void );
@@ -80,7 +86,12 @@ private:
     typedef material_map::iterator material_map_iterator;
     typedef material_map::const_iterator const_material_map_iterator;
 
+    typedef std::map < int, std::string> landclass_map;
+    typedef landclass_map::iterator landclass_map_iterator;
+    typedef landclass_map::const_iterator const_landclass_map_iterator;
+
     material_map matlib;
+    landclass_map landclasslib;
     
 public:
 
@@ -93,6 +104,8 @@ public:
     // find a material record by material name
     SGMaterial *find( const std::string& material, SGVec2f center ) const;
     SGMaterial *find( const std::string& material, const SGGeod& center ) const;
+    SGMaterial *find( const int lc, SGVec2f center ) const;
+    SGMaterial *find( const int lc, const SGGeod& center ) const;
 
     /**
      * Material lookup involves evaluation of position and SGConditions to