openglwindow.cpp Example File | Qt GUI 5.12.9

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- openglwindow.cpp Example File
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# openglwindow.cpp Example File

openglwindow/openglwindow.cpp

     /****************************************************************************
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     #include "openglwindow.h"

     #include <QtCore/QCoreApplication>

     #include <QtGui/QOpenGLContext>
     #include <QtGui/QOpenGLPaintDevice>
     #include <QtGui/QPainter>

     OpenGLWindow::OpenGLWindow(QWindow *parent)
         : QWindow(parent)
         , m_animating(false)
         , m_context(0)
         , m_device(0)
     {
         setSurfaceType(QWindow::OpenGLSurface);
     }

     OpenGLWindow::~OpenGLWindow()
     {
         delete m_device;
     }
     void OpenGLWindow::render(QPainter *painter)
     {
         Q_UNUSED(painter);
     }

     void OpenGLWindow::initialize()
     {
     }

     void OpenGLWindow::render()
     {
         if (!m_device)
             m_device = new QOpenGLPaintDevice;

         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

         m_device->setSize(size() * devicePixelRatio());
         m_device->setDevicePixelRatio(devicePixelRatio());

         QPainter painter(m_device);
         render(&painter);
     }

     void OpenGLWindow::renderLater()
     {
         requestUpdate();
     }

     bool OpenGLWindow::event(QEvent *event)
     {
         switch (event->type()) {
         case QEvent::UpdateRequest:
             renderNow();
             return true;
         default:
             return QWindow::event(event);
         }
     }

     void OpenGLWindow::exposeEvent(QExposeEvent *event)
     {
         Q_UNUSED(event);

         if (isExposed())
             renderNow();
     }

     void OpenGLWindow::renderNow()
     {
         if (!isExposed())
             return;

         bool needsInitialize = false;

         if (!m_context) {
             m_context = new QOpenGLContext(this);
             m_context->setFormat(requestedFormat());
             m_context->create();

             needsInitialize = true;
         }

         m_context->makeCurrent(this);

         if (needsInitialize) {
             initializeOpenGLFunctions();
             initialize();
         }

         render();

         m_context->swapBuffers(this);

         if (m_animating)
             renderLater();
     }

     void OpenGLWindow::setAnimating(bool animating)
     {
         m_animating = animating;

         if (animating)
             renderLater();
     }