Use a custom 'findDataFile' method in key places, and hook this into a callback set on SGModelLib.

simgear/scene/material/makeEffect.cxx

@@ -128,7 +128,7 @@ Effect* makeEffect(const string& name,
     string effectFileName(name);
     effectFileName += ".eff";
     string absFileName
-        = osgDB::findDataFile(effectFileName, options);
+        = SGModelLib::findDataFile(effectFileName, options);
     if (absFileName.empty()) {
         SG_LOG(SG_INPUT, SG_ALERT, "can't find \"" << effectFileName << "\"");
         return 0;

simgear/scene/model/ModelRegistry.cxx

@@ -207,7 +207,7 @@ ModelRegistry::readImage(const string& fileName,
     {
         if (iter != imageCallbackMap.end() && iter->second.valid())
             return iter->second->readImage(fileName, opt);
-        string absFileName = findDataFile(fileName, opt);
+        string absFileName = SGModelLib::findDataFile(fileName, opt);
         if (!fileExists(absFileName)) {
             SG_LOG(SG_IO, SG_ALERT, "Cannot find image file \""
                    << fileName << "\"");
@@ -297,7 +297,7 @@ string OSGSubstitutePolicy::substitute(const string& name,
 {
     string fileSansExtension = getNameLessExtension(name);
     string osgFileName = fileSansExtension + ".osg";
-    string absFileName = findDataFile(osgFileName, opt);
+    string absFileName = SGModelLib::findDataFile(osgFileName, opt);
     return absFileName;
 }
 

simgear/scene/model/SGReaderWriterXML.cxx

@@ -202,21 +202,21 @@ sgLoad3DModel_internal(const string &path,
     SGSharedPtr<SGPropertyNode> prop_root;
     osg::Node *(*load_panel)(SGPropertyNode *)=0;
     osg::ref_ptr<SGModelData> data;
-
+    SGPath modelpath;
+        
     if (xmlOptions) {
         prop_root = xmlOptions->getPropRoot();
         load_panel = xmlOptions->getLoadPanel();
         data = xmlOptions->getModelData();
     }
+    
+    
+    modelpath = SGModelLib::findDataFile(path);
+    
     if (!prop_root) {
         prop_root = new SGPropertyNode;
     }
 
-    osgDB::FilePathList filePathList;
-    filePathList = osgDB::Registry::instance()->getDataFilePathList();
-    filePathList.push_front(std::string());
-
-    SGPath modelpath = osgDB::findFileInPath(path, filePathList);
     if (modelpath.str().empty()) {
         SG_LOG(SG_INPUT, SG_ALERT, "Failed to load file: \"" << path << "\"");
         return 0;
@@ -262,7 +262,7 @@ sgLoad3DModel_internal(const string &path,
     = new SGReaderWriterXMLOptions(*options_);
     options->setPropRoot(prop_root);
     options->setLoadPanel(load_panel);
-
+    
     // Assume that textures are in
     // the same location as the XML file.
     if (!model) {
@@ -345,6 +345,7 @@ sgLoad3DModel_internal(const string &path,
         options = new SGReaderWriterXMLOptions(*options_);
         options->setPropRoot(prop_root);
         options->setLoadPanel(load_panel);
+        
         try {
             submodel = sgLoad3DModel_internal(submodelpath.str(), options.get(),
                                               sub_props->getNode("overlay"));

simgear/scene/model/modellib.cxx

@@ -45,7 +45,10 @@ using namespace simgear;
 osgDB::RegisterReaderWriterProxy<SGReaderWriterXML> g_readerWriter_XML_Proxy;
 ModelRegistryCallbackProxy<LoadOnlyCallback> g_xmlCallbackProxy("xml");
 
-
+SGPropertyNode_ptr SGModelLib::static_propRoot;
+SGModelLib::panel_func SGModelLib::static_panelFunc = NULL;
+SGModelLib::resolve_func SGModelLib::static_resolver = NULL;
+
 ////////////////////////////////////////////////////////////////////////
 // Implementation of SGModelLib.
 ////////////////////////////////////////////////////////////////////////
@@ -54,6 +57,34 @@ void SGModelLib::init(const string &root_dir)
     osgDB::Registry::instance()->getDataFilePathList().push_front(root_dir);
 }
 
+void SGModelLib::setPropRoot(SGPropertyNode* root)
+{
+  static_propRoot = root;
+}
+    
+void SGModelLib::setPanelFunc(panel_func pf)
+{
+  static_panelFunc = pf;
+}
+
+void SGModelLib::setResolveFunc(resolve_func rf)
+{
+  static_resolver = rf;
+}
+
+std::string SGModelLib::findDataFile(const std::string& file, 
+  const osgDB::ReaderWriter::Options* opts)
+{
+  if (static_resolver) {
+    SGPath p = static_resolver(file);
+    if (p.exists()) {
+      return p.str();
+    }
+  }
+  
+  return osgDB::findDataFile(file, opts);
+}
+
 SGModelLib::SGModelLib()
 {
 }
@@ -87,8 +118,10 @@ SGModelLib::loadModel(const string &path,
                        SGModelData *data)
 {
     osg::ref_ptr<SGReaderWriterXMLOptions> opt = new SGReaderWriterXMLOptions(*(osgDB::Registry::instance()->getOptions()));
-    opt->setPropRoot(prop_root);
+    opt->setPropRoot(prop_root ? prop_root: static_propRoot.get());
     opt->setModelData(data);
+    opt->setLoadPanel(static_panelFunc);
+    
     osg::Node *n = loadFile(path, opt.get());
     if (n && n->getName().empty())
         n->setName("Direct loaded model \"" + path + "\"");
@@ -96,17 +129,6 @@ SGModelLib::loadModel(const string &path,
 
 }
 
-osg::Node*
-SGModelLib::loadModel(const string &path,
-                                SGPropertyNode *prop_root,
-                                panel_func pf)
-{
-    osg::ref_ptr<SGReaderWriterXMLOptions> opt = new SGReaderWriterXMLOptions(*(osgDB::Registry::instance()->getOptions()));
-    opt->setPropRoot(prop_root);
-    opt->setLoadPanel(pf);
-    return loadFile(path, opt.get());
-}
-
 osg::Node*
 SGModelLib::loadPagedModel(const string &path,
                            SGPropertyNode *prop_root,
@@ -118,8 +140,10 @@ SGModelLib::loadPagedModel(const string &path,
     plod->setRange(0, 0.0, 50.0*SG_NM_TO_METER);
 
     osg::ref_ptr<SGReaderWriterXMLOptions> opt = new SGReaderWriterXMLOptions(*(osgDB::Registry::instance()->getOptions()));
-    opt->setPropRoot(prop_root);
+    opt->setPropRoot(prop_root ? prop_root: static_propRoot.get());
     opt->setModelData(data);
+    opt->setLoadPanel(static_panelFunc);
+    
     plod->setReaderWriterOptions(opt.get());
     return plod;
 }

simgear/scene/model/modellib.hxx

@@ -27,11 +27,10 @@
 #include <string>
 
 #include <osg/Node>
+#include <osgDB/ReaderWriter>
 
 #include <simgear/props/props.hxx>
-
+#include <simgear/misc/sg_path.hxx>
-using std::map;
-using std::string;
 
 namespace simgear {
 
@@ -45,33 +44,41 @@ class SGModelLib
 public:
     typedef osg::Node *(*panel_func)(SGPropertyNode *);
 
-    static void init(const string &root_dir);
+    typedef SGPath (*resolve_func)(const std::string& path);
+
+    static void init(const std::string &root_dir);
+
+    static void setPropRoot(SGPropertyNode* root);
+    
+    static void setPanelFunc(panel_func pf);
+    
+    static void setResolveFunc(resolve_func rf);
 
     // Load a 3D model (any format)
     // data->modelLoaded() will be called after the model is loaded
-    static osg::Node* loadModel(const string &path,
+    static osg::Node* loadModel(const std::string &path,
-                                SGPropertyNode *prop_root,
+                                SGPropertyNode *prop_root = NULL,
                                 SGModelData *data=0);
 
-    // Load a 3D model (any format)
-    // with a panel_func to load a panel
-    static osg::Node* loadModel(const string &path,
-                                SGPropertyNode *prop_root,
-                                panel_func pf);
-
     // Load a 3D model (any format) through the DatabasePager.
     // Most models should be loaded using this function!
     // This function will initially return an SGPagedLOD node.
     // data->modelLoaded() will be called after the model is loaded and
     // connected to the scene graph. See AIModelData on how to use this.
     // NOTE: AIModelData uses observer_ptr to avoid circular references.
-    static osg::Node* loadPagedModel(const string &path,
+    static osg::Node* loadPagedModel(const std::string &path,
-                                     SGPropertyNode *prop_root,
+                                     SGPropertyNode *prop_root = NULL,
                                      SGModelData *data=0);
 
+    static std::string findDataFile(const std::string& file, const osgDB::ReaderWriter::Options* opts = NULL); 
 protected:
     SGModelLib();
     ~SGModelLib ();
+    
+private:
+  static SGPropertyNode_ptr static_propRoot;
+  static panel_func static_panelFunc;
+  static resolve_func static_resolver;
 };
 
 
@@ -83,7 +90,7 @@ protected:
 class SGModelData : public osg::Referenced {
 public:
     virtual ~SGModelData() {}
-    virtual void modelLoaded(const string& path, SGPropertyNode *prop,
+    virtual void modelLoaded(const std::string& path, SGPropertyNode *prop,
                              osg::Node* branch) = 0;
 };