Fixed OpenGL viewport being updated at each frame

That could cause ratio flickering on paint() on some devices

src/interface/modeler/quickapp/OpenGLView.cpp

@@ -18,6 +18,8 @@ OpenGLView::OpenGLView(QQuickItem *parent) :
     mouse_button = Qt::NoButton;
 
     connect(this, SIGNAL(windowChanged(QQuickWindow*)), this, SLOT(handleWindowChanged(QQuickWindow*)));
+    connect(this, SIGNAL(widthChanged()), this, SLOT(handleResize()));
+    connect(this, SIGNAL(heightChanged()), this, SLOT(handleResize()));
     startTimer(50);
 }
 
@@ -45,9 +47,15 @@ void OpenGLView::paint()
     {
         renderer->initialize();
         initialized = true;
+        resized = true;
+    }
+
+    if (resized)
+    {
+        renderer->resize(width(), height());
+        resized = false;
     }
 
-    renderer->resize(width(), height());
     renderer->prepareOpenGLState();
     renderer->paint();
 
@@ -57,6 +65,11 @@ void OpenGLView::paint()
     }
 }
 
+void OpenGLView::handleResize()
+{
+    resized = true;
+}
+
 void OpenGLView::wheelEvent(QWheelEvent *event)
 {
     if (not acceptInputs())

src/interface/modeler/quickapp/OpenGLView.h

@@ -17,6 +17,7 @@ public:
 public slots:
     void handleWindowChanged(QQuickWindow *win);
     void paint();
+    void handleResize();
 
 protected:
     virtual void wheelEvent(QWheelEvent *event) override;
@@ -31,6 +32,7 @@ private:
 
 private:
     bool initialized;
+    bool resized;
     MainModelerWindow *window;
     OpenGLRenderer *renderer;