use utility class for image conversion

libs_required/ACG/GL/globjects.cc

@@ -51,6 +51,7 @@
 #include <ACG/GL/globjects.hh>
 #include <ACG/GL/GLFormatInfo.hh>
 #include <ACG/ShaderUtils/GLSLShader.hh>
+#include <ACG/Utils/ImageConversion.hh>
 
 #include <QImage>
 #include <QGLWidget>
@@ -640,7 +641,7 @@ bool Texture2D::loadFromFile( const std::string& _filename, GLenum _minFilter, G
       if (mipmaps)
         autogenerateMipMaps();
 
-      QImage gltex = QGLWidget::convertToGLFormat ( qtex );
+      QImage gltex = ACG::Util::convertToGLFormat(gltex);
 
       setData(0, GL_RGBA, gltex.width(), gltex.height(), GL_RGBA, GL_UNSIGNED_BYTE, gltex.bits());
     }

libs_required/ACG/Scenegraph/TextNode.cc

@@ -63,6 +63,7 @@
 #include <ACG/GL/acg_glew.hh>
 
 #include "TextNode.hh"
+#include "../Utils/ImageConversion.hh"
 
 
 //== NAMESPACES ===============================================================
@@ -405,7 +406,7 @@ updateFont() {
   painter.end();
 
   // convert finalImage to an OpenGL friendly format
-  finalImage = QGLWidget::convertToGLFormat(finalImage);
+  finalImage = ACG::Util::convertToGLFormat(finalImage);
 
   // generate a new texture from finalImage
   if (!texture_)