Work around osg Registry path list problems

The OSG reader plugins overwrite the path list passed in options with the local
directory of the file being read, forcing you to set the path list in
the Registry. I think this a bug, but in the meantime here's a workaround.

diff --git a/simgear/scene/model/ModelRegistry.cxx b/simgear/scene/model/ModelRegistry.cxx
index b2dfa1b611d978d3e6e28967fa40a31c1fceba83..6ae694b8e6a9682355512d14c5617fbec287b3b4 100644 (file)
--- a/simgear/scene/model/ModelRegistry.cxx
+++ b/simgear/scene/model/ModelRegistry.cxx
@@ -198,6 +198,34 @@ public:
     material->setColorMode(Material::AMBIENT_AND_DIFFUSE);
   }
 };
+
+// Work around an OSG bug - the file loaders don't use the file path
+// in options while the file is being loaded.
+
+struct OptionsPusher {
+    FilePathList localPathList;
+    OptionsPusher(const ReaderWriter::Options* options)
+    {
+        Registry* registry = Registry::instance();
+        localPathList = registry->getDataFilePathList();
+        const FilePathList& regPathList = registry->getDataFilePathList();
+        const FilePathList& optionsPathList = options->getDatabasePathList();
+        for (FilePathList::const_iterator iter = optionsPathList.begin();
+             iter != optionsPathList.end();
+             ++iter) {
+            if (find(regPathList.begin(), regPathList.end(), *iter)
+                == regPathList.end())
+                localPathList.push_front(*iter);
+        }
+        // Save the current Registry path list and install the augmented one.
+        localPathList.swap(registry->getDataFilePathList());
+    }
+    ~OptionsPusher()
+    {
+        // Restore the old path list
+        localPathList.swap(Registry::instance()->getDataFilePathList());
+    }
+};
 } // namespace
 
 ReaderWriter::ReadResult
@@ -207,9 +235,11 @@ ModelRegistry::readImage(const string& fileName,
     OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(readerMutex);
     CallbackMap::iterator iter
         = imageCallbackMap.find(getFileExtension(fileName));
+    // XXX Workaround for OSG plugin bug
+    OptionsPusher pusher(opt);
     if (iter != imageCallbackMap.end() && iter->second.valid())
         return iter->second->readImage(fileName, opt);
-    string absFileName = findDataFile(fileName, opt);
+    string absFileName = findDataFile(fileName);
     if (!fileExists(absFileName)) {
         SG_LOG(SG_IO, SG_ALERT, "Cannot find image file \""
                << fileName << "\"");
@@ -360,6 +390,8 @@ ModelRegistry::readNode(const string& fileName,
                         const ReaderWriter::Options* opt)
 {
     OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(readerMutex);
+    // XXX Workaround for OSG plugin bug.
+    OptionsPusher pusher(opt);
     Registry* registry = Registry::instance();
     ReaderWriter::ReadResult res;
     Node* cached = 0;