added missing gl calls to fix GLErrors with QOpenGLWidget

widgets/glWidget/QtBaseViewer.cc

@@ -721,15 +721,12 @@ void glViewer::drawScene(double _aspect)
     postproc_->resolveStereoAnyglyph(properties_.viewerId());
 
   // =================================================================================
-
+  glBindFramebuffer(GL_FRAMEBUFFER, backbufferFbo);
   glDrawBuffer(backbufferTarget);
-
   // unbind vbo for qt log window
   ACG::GLState::bindBuffer(GL_ARRAY_BUFFER, 0);
-
   ACG::GLState::activeTexture(GL_TEXTURE0);
   ACG::GLState::bindTexture(GL_TEXTURE_2D, 0);
-
 //  fbo.release();
 //
 //  QRect blitRect(0,0,glstate_->viewport_width(),glstate_->viewport_height());
@@ -739,7 +736,6 @@ void glViewer::drawScene(double _aspect)
 //  //time.restart();
 //  QGLFramebufferObject::blitFramebuffer( 0 , blitRect, &fbo, blitRect , GL_COLOR_BUFFER_BIT );
 //  //std::cerr << "Elapsed for blit: " << time.elapsed() << std::endl;
-
   glFinish();
 
   frame_time_ = timer.elapsed();
@@ -747,7 +743,6 @@ void glViewer::drawScene(double _aspect)
   
   // Inside the glWidget rendering, the system should not send extra updates
   properties_.blockSignals(false);
-
 }
 
 
@@ -921,7 +916,6 @@ void glViewer::home()
 void glViewer::viewAll()
 {
   makeCurrent();
-
   // update scene graph (get new bounding box and set projection right, including near and far plane)
   properties_.lockUpdate();
 
@@ -996,7 +990,6 @@ void glViewer::initializeGL()
   glstate_->translate(0.0, 0.0, -3.0);
   setHome();
 
-
   // pixel transfer
   glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
   glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
@@ -1020,7 +1013,6 @@ void glViewer::initializeGL()
     ACG::SceneGraph::analyzeSceneGraph(sceneGraphRoot_,maxPases,bbmin,bbmax);
 
     sceneGraph ( sceneGraphRoot_, maxPases,bbmin,bbmax,true);
-
     viewAll();
   }
 }
@@ -1033,7 +1025,6 @@ void glViewer::paintGL(double _aspect)
 {
   if (!initialized_)
     initializeGL ();
-
   if (!properties_.updateLocked())
   {
     properties_.lockUpdate();
@@ -1074,7 +1065,8 @@ void glViewer::paintGL(double _aspect)
 
     glPopAttrib ();
   }
-
+  glBindBuffer(GL_ARRAY_BUFFER, 0);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 }