Merge branch 'fixGLErrorOnSnapshot' into 'unstable'

fixed #3 by moving the call to make current to the top of snapshot

See merge request !36

widgets/glWidget/QtBaseViewer.cc

@@ -2200,6 +2200,7 @@ void glViewer::slotPropertiesUpdated() {
 }
 
 void glViewer::snapshot(QImage& _image, int _width, int _height, bool _alpha, bool _hideCoordsys, int samples) {
+    makeCurrent();
 
     int w = 0, h = 0, bak_w = 0, bak_h = 0, left = 0, bottom = 0;
     
@@ -2240,7 +2241,6 @@ void glViewer::snapshot(QImage& _image, int _width, int _height, bool _alpha, bo
     // it will fall back to the maximal supported number of samples
     format.setSamples(samples);
 
-    makeCurrent();
     QFramebufferObject fb(w,h,format);
 
     if ( fb.isValid() ){