qt5base-lts/examples/gui/openglwindow/openglwindow.cpp

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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** 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.
** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
** of its contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "openglwindow.h"
#include <QtCore/QCoreApplication>
#include <QtGui/QOpenGLContext>
#include <QtGui/QOpenGLPaintDevice>
#include <QtGui/QPainter>
//! [1]
OpenGLWindow::OpenGLWindow(QWindow *parent)
: QWindow(parent)
, m_update_pending(false)
, m_animating(false)
, m_context(0)
, m_device(0)
{
setSurfaceType(QWindow::OpenGLSurface);
}
//! [1]
OpenGLWindow::~OpenGLWindow()
{
delete m_device;
}
//! [2]
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);
}
//! [2]
//! [3]
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:
renderNow();
return true;
default:
return QWindow::event(event);
}
}
void OpenGLWindow::exposeEvent(QExposeEvent *event)
{
Q_UNUSED(event);
if (isExposed())
renderNow();
}
void OpenGLWindow::resizeEvent(QResizeEvent *event)
{
Q_UNUSED(event);
if (isExposed())
renderNow();
}
//! [3]
//! [4]
void OpenGLWindow::renderNow()
{
if (!isExposed())
return;
m_update_pending = false;
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();
}
//! [4]
//! [5]
void OpenGLWindow::setAnimating(bool animating)
{
m_animating = animating;
if (animating)
renderLater();
}
//! [5]