added transparency support,

need to sort the transparent things to the back

QtMeshViewer/Source/OglViewerWidget.cpp

@@ -187,7 +187,11 @@ void OglViewerWidget::initializeGL()
 	glEnable(GL_DEPTH_TEST);
 
 	// Enable back face culling
-	glEnable(GL_CULL_FACE);
+	//glEnable(GL_CULL_FACE);
+
+	// Enable transparency
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
 	m_dataEngine = new GeometryEngine(this);
 	setConnections();