Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. Scaling QOpenGLWidget
Forum Update on Monday, May 27th 2025

Scaling QOpenGLWidget

Scheduled Pinned Locked Moved Unsolved General and Desktop
qopenglwidgetopengl
4 Posts 3 Posters 1.7k Views
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • V Offline
    V Offline
    Vitek
    wrote on 16 Mar 2016, 17:33 last edited by
    #1

    Why does scaling work with no matter that i turned glViewport in resizeGL or not?

    Window::Window(QWidget *parent, Qt::WindowFlags f) : QOpenGLWidget(parent, f)
    {
    
    }
    
    void Window::initializeGL()
    {
        QOpenGLFunctions_1_5 *f = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_1_5>();
        f->glClearColor(.0f, .0f, .0f, .0f);
        f->glShadeModel(GL_FLAT);
    
    }
    
    void Window::resizeGL(int w, int h)
    {
        QOpenGLFunctions_1_5 *f = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_1_5>();
      //  f->glViewport(0, 0, 1000, 1000);
    }
    
    void Window::paintGL()
    {
        QOpenGLFunctions_1_5 *f = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_1_5>();
        f->glClear(GL_COLOR_BUFFER_BIT);
        f->glColor3f (1.0, 1.0, 1.0);
        f->glBegin(GL_POLYGON);
           f->glVertex2f(0.0, 0.0);
           f->glVertex2f(0.0, 0.5);
           f->glVertex2f(0.5, 0.5);
           f->glVertex2f(0.5, 0.0);
        f->glEnd();
        f->glFlush();
    }
    
    
    1 Reply Last reply
    0
    • Y Offline
      Y Offline
      yoavmil
      wrote on 16 Mar 2016, 18:40 last edited by
      #2

      @Vitek said:

      glViewport

      try changing your clearColor to some thing other than black, see what happens.
      f->glClearColor(.5f, .5f, .5f, 1.0f);

      1 Reply Last reply
      0
      • V Offline
        V Offline
        Vitek
        wrote on 17 Mar 2016, 13:06 last edited by
        #3

        Background color changed. It is all. If change glViewport, for example as f->glViewport(0, 0, 2000, 2000); that nothing happened.

        1 Reply Last reply
        0
        • S Offline
          S Offline
          SGaist
          Lifetime Qt Champion
          wrote on 17 Mar 2016, 21:52 last edited by
          #4

          Hi,

          It's a little bit more complex than that. See this article about the various transformation that you can apply.

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          1 Reply Last reply
          1

          1/4

          16 Mar 2016, 17:33

          • Login

          • Login or register to search.
          1 out of 4
          • First post
            1/4
            Last post
          0
          • Categories
          • Recent
          • Tags
          • Popular
          • Users
          • Groups
          • Search
          • Get Qt Extensions
          • Unsolved