From Mathias Froehlich, "If you want to have that qfont plugin loader, this is the updated

implementation which uses osgQt and includes the changes to make fonts load
without a file on disk."

src/osgPlugins/CMakeLists.txt

@@ -221,6 +221,10 @@ IF(FREETYPE_FOUND)
     ADD_SUBDIRECTORY(freetype)
 ENDIF()
 
+IF (QT4_FOUND)
+    ADD_SUBDIRECTORY(qfont)
+ENDIF()
+
 IF(ZLIB_FOUND)
     ADD_SUBDIRECTORY(zip)
 ENDIF()

src/osgPlugins/qfont/CMakeLists.txt

@@ -0,0 +1,6 @@
+INCLUDE_DIRECTORIES(${QT_INCLUDE_DIR})
+SET(TARGET_SRC ReaderQFont.cpp)
+SET(TARGET_ADDED_LIBRARIES osgText osgQt)
+
+SET(TARGET_LIBRARIES_VARS ${QT_QTCORE_LIBRARY_RELEASE} ${QT_QTGUI_LIBRARY_RELEASE})
+SETUP_PLUGIN(qfont)

src/osgPlugins/qfont/ReaderQFont.cpp

@@ -0,0 +1,66 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 2009-2010 Mathias Froehlich
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+#include <osgDB/FileNameUtils>
+#include <osgDB/Registry>
+#include <osgText/Font>
+
+#include <QtCore/QThread>
+#include <QtGui/QApplication>
+#include <QtGui/QFont>
+#include <QtGui/QFontDatabase>
+
+#include <osgQt/QFontImplementation>
+
+namespace osgQFont {
+
+class ReaderQFont : public osgDB::ReaderWriter
+{
+    public:
+        ReaderQFont()
+        {
+            supportsExtension("qfont", "Qt font meta loader");
+        }
+        
+        virtual const char* className() const { return "QFont Font Reader"; }
+        
+        virtual ReadResult readObject(const std::string& file, const osgDB::ReaderWriter::Options* options) const
+        {
+            if (!acceptsExtension(osgDB::getLowerCaseFileExtension(file)))
+                return ReadResult::FILE_NOT_HANDLED;
+
+            if (!QApplication::instance())
+            {
+                osg::notify(osg::WARN) << "Trying to load qfont \"" << file << "\" from within a non qt application!" << std::endl;
+                return ReadResult::FILE_NOT_FOUND;
+            }
+
+            if (!QFontDatabase::supportsThreadedFontRendering() && QApplication::instance()->thread() != QThread::currentThread())
+            {
+                osg::notify(osg::WARN) << "Trying to load qfont \"" << file << "\" from a non gui thread "
+                    "within qt application without threaded font rendering!" << std::endl;
+                return ReadResult::FILE_NOT_FOUND;
+            }
+
+            QFont font;
+            if (!font.fromString(QString::fromStdString(osgDB::getNameLessExtension(file))))
+                return ReadResult::FILE_NOT_FOUND;
+
+            return new osgText::Font(new osgQt::QFontImplementation(font));
+        }
+};
+
+// now register with Registry to instantiate the above
+// reader/writer.
+REGISTER_OSGPLUGIN(qfont, ReaderQFont)
+
+}

src/osgText/Font.cpp

@@ -83,16 +83,17 @@ std::string osgText::findFontFile(const std::string& str)
     }
 
     // Not found, return empty string
-    osg::notify(osg::WARN)<<"Warning: font file \""<<str<<"\" not found."<<std::endl;    
+    osg::notify(osg::INFO)<<"Warning: font file \""<<str<<"\" not found."<<std::endl;    
     return std::string();
 }
 
 osgText::Font* osgText::readFontFile(const std::string& filename, const osgDB::ReaderWriter::Options* userOptions)
 {
-    if (filename=="") return 0;
+    if (filename.empty()) return 0;
 
     std::string foundFile = findFontFile(filename);
-    if (foundFile.empty()) return 0;
+    if (foundFile.empty())
+        foundFile = filename;
     
     OpenThreads::ScopedLock<OpenThreads::Mutex> lock(s_FontFileMutex);
 
@@ -149,10 +150,11 @@ osgText::Font* osgText::readFontStream(std::istream& stream, const osgDB::Reader
 
 osg::ref_ptr<Font> osgText::readRefFontFile(const std::string& filename, const osgDB::ReaderWriter::Options* userOptions)
 {
-    if (filename=="") return 0;
+    if (filename.empty()) return 0;
 
     std::string foundFile = findFontFile(filename);
-    if (foundFile.empty()) return 0;
+    if (foundFile.empty())
+        foundFile = filename;
     
     OpenThreads::ScopedLock<OpenThreads::Mutex> lock(s_FontFileMutex);
 
@@ -252,7 +254,7 @@ const Font::FontImplementation* Font::getImplementation() const
 std::string Font::getFileName() const
 {
     if (_implementation.valid()) return _implementation->getFileName();
-    return "";
+    return std::string();
 }
 
 void Font::setGlyphImageMargin(unsigned int margin)