Hi everyone, I am trying to add a QGLWidget in an application I am working on. However, I'm running into an issue which is that if I try and add the QGLWidget to a QMdiArea, there is a very noticeable spatial lag between where the Qt window is drawn and the OpenGL canvas when dragging the MDI sub-window around. In fact, the Qt window seems to drag behind the OpenGL canvas.
Here's a short screencast demonstrating this problem, slowed down by a factor of 10: https://www.youtube.com/watch?v=k7T7Sev91c8 The code I'm using to produce this is included below (in C++ with Qt4) and can also be found here: https://github.com/astrofrog/qt-build-sandbox/blob/master/opengl/opengl_mdi.cpp This issue does NOT happen if I don't use a QMdiArea. Does anyone know what might be causing this problem, and how to fix it? Is it a bug in Qt? Thanks in advance for any help! Cheers, Tom --- #include <QApplication> #include <QMenuBar> #include <QMainWindow> #include <QMdiArea> #include <QGLWidget> #include <QMdiSubWindow> class PlainGLWidget : public QGLWidget { protected: virtual void paintGL(); }; void PlainGLWidget::paintGL() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); } int main(int argc, char *argv[]) { QApplication app(argc, argv); QMainWindow *window = new QMainWindow; QMdiArea *mdi = new QMdiArea; window->setCentralWidget(mdi); PlainGLWidget *viewer = new PlainGLWidget; viewer->resize(600,600); QMdiSubWindow *sub = new QMdiSubWindow; sub->setWidget(viewer); mdi->addSubWindow(sub); sub->resize(600,600); window->show(); window->raise(); return app.exec(); } _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest