openglwindow.cpp Example File | Qt GUI 5.6

Qt 5.6 | Qt GUI | OpenGL Window Example | openglwindow.cpp Example File

Qt 5.6.2 Reference Documentation

# openglwindow.cpp Example File

openglwindow/openglwindow.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
      **
      ** This file is part of the documentation of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** You may use this file under the terms of the BSD license as follows:
      **
      ** "Redistribution and use in source and binary forms, with or without
      ** modification, are permitted provided that the following conditions are
      ** met:
      **   * Redistributions of source code must retain the above copyright
      **     notice, this list of conditions and the following disclaimer.
      **   * Redistributions in binary form must reproduce the above copyright
      **     notice, this list of conditions and the following disclaimer in
      **     the documentation and/or other materials provided with the
      **     distribution.
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      **     contributors may be used to endorse or promote products derived
      **     from this software without specific prior written permission.
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      **
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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_update_pending(false)
          , 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());

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

      void OpenGLWindow::renderLater()
      {
          if (!m_update_pending) {
              m_update_pending = true;
              QCoreApplication::postEvent(this, new QEvent(QEvent::UpdateRequest));
          }
      }

      bool OpenGLWindow::event(QEvent *event)
      {
          switch (event->type()) {
          case QEvent::UpdateRequest:
              m_update_pending = false;
              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();
      }