我有一个隐藏的QOpenGLWidget（Qt 5.4.2，不是QGLWidget），并且我想基本上连续地进行抓（）或抓帧缓冲区（）以获取其内容（并将其写入磁盘）。该小部件在可见时呈现良好，但在隐藏时则不呈现。如果我先执行show（）然后执行hide（）调用，则它可以正常工作。这似乎很奇怪，因为根据文档，QOpenGLWidget在内部确实已渲染到帧缓冲区。实现此目的的最简单方法是什么（如果可能，而无需创建另一个帧缓冲区）？
奖励点在于能够使用QOpenGLWidget作为其视口并使用自定义OpenGL绘制的QGraphicsItems捕获屏幕外的QGraphicsView ...
最佳答案
更新2：QOpenGLWidget中的corresponding bug在Qt 5.10中似乎已修复，因此我建议再次使用该类。尽管您可能要等待this bug也要修复...
更新1：添加了3，使用自定义QWindow派生的类的最佳解决方案
1-QOpenGLWidget
如果隐藏的QOpenGLWidget确实分配了帧缓冲区（不确定是否会发生这种情况），则仍然无法手动绑定它，因为您无法获取缓冲区ID。另外，没有调用必要的函数initializeGL（），resizeGL（）和paintGL，并且所有函数handle（），grabFramebuffer和render（）均未正常工作。这是（imo）一种在屏幕外绘制小部件的解决方法。设置所有必要的东西后，您可以直接调用paintGL：
class GLWidget: public QOpenGLWidget
{
public:
GLWidget(QWidget * parent = nullptr);
private:
bool m_isInitialized = false;
QOpenGLFramebufferObject m_fbo = nullptr;
};
void GLWidget::drawOffscreen()
{
//the context should be valid. make sure it is current for painting
makeCurrent();
if (!m_isInitialized)
{
initializeGL();
resizeGL(width(), height());
}
if (!m_fbo || m_fbo->width() != width() || m_fbo->height() != height())
{
//allocate additional? FBO for rendering or resize it if widget size changed
delete m_fbo;
QOpenGLFramebufferObjectFormat format;
format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
m_fbo = new QOpenGLFramebufferObject(width(), height(), format);
resizeGL(width(), height());
}
//#1 DOES NOT WORK: bind FBO and render() widget
m_fbo->bind();
QOpenGLPaintDevice fboPaintDev(width(), height());
QPainter painter(&fboPaintDev);
painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);
render(&painter);
painter.end();
//You could now grab the content of the framebuffer we've rendered to
QImage image1 = m_fbo->toImage();
image1.save(QString("fb1.png"));
m_fbo->release();
//#1 --------------------------------------------------------------
//#2 WORKS: bind FBO and render stuff with paintGL() call
m_fbo->bind();
paintGL();
//You could now grab the content of the framebuffer we've rendered to
QImage image2 = m_fbo->toImage();
image2.save(QString("fb2.png"));
m_fbo->release();
//#2 --------------------------------------------------------------
//bind default framebuffer again. not sure if this necessary
//and isn't supposed to use defaultFramebuffer()...
m_fbo->bindDefault();
doneCurrent();
}
void GLWidget::paintGL()
{
//When doing mixed QPainter/OpenGL rendering make sure to use a QOpenGLPaintDevice, otherwise only OpenGL content is visible!
//I'm not sure why, because according to the docs (http://doc.qt.io/qt-5/topics-graphics.html) this is supposed to be the same...
QOpenGLPaintDevice fboPaintDev(width(), height());
QPainter painter(&fboPaintDev);
painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);
//This is what you'd use (and what would work) if the widget was visible
//QPainter painter;
//painter.begin(this);
//now start OpenGL painting
painter.beginNativePainting();
glClearColor(0.5f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
...
painter.endNativePainting();
//draw non-OpenGL stuff with QPainter
painter.drawText(20, 40, "Foo");
...
painter.end();
}
2-具有QOpenGLWidget视口的QGraphicsView
在为render（）提供QOpenGLPaintDevice时，它可以按预期工作：
MainWindow::MainWindow()
{
scene = new QGraphicsScene;
hiddenView = new QGraphicsView(scene);
hiddenGLWidget = new QOpenGLWidget;
hiddenView->setViewport(hiddenGLWidget);
//hiddenView->setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
//hiddenView->show();
}
void MainWindow::screenshot()
{
//try regular grab functions
QPixmap pixmap1 = hiddenView->grab(); //image with scrollbars, no OpenGL content
pixmap1.save("bla1.png");
QPixmap pixmap2 = hiddenGLWidget->grab(); //produces an empty image
pixmap2.save("bla2.png");
//try grabbing only the QOpenGLWidget framebuffer
QImage image1 = hiddenGLWidget->grabFramebuffer(); //null image
image1.save("bla3.png");
//WORKS: render via FBO
hiddenGLWidget->makeCurrent();
QOpenGLFramebufferObjectFormat format;
format.setAttachment(QOpenGLFramebufferObject::CombinedDepthStencil);
QOpenGLFramebufferObject * fbo = new QOpenGLFramebufferObject(hiddenView->width(), hiddenView->height(), format);
fbo->bind();
QOpenGLPaintDevice fboPaintDev(hiddenView->width(), hiddenView->height());
QPainter painter(&fboPaintDev);
painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);
hiddenView->render(&painter); //WORKS and captures mixed OpenGL and non-OpenGL QGraphicsitems
//hiddenView->repaint(); //does not work
//hiddenView->scene()->render(&painter); //does not work
//hiddenGLWidget->paintGL(); //might work. can not call, protected
//hiddenGLWidget->render(&painter); //does not work
//hiddenGLWidget->repaint(); //does not work
painter.end();
QImage image2 = fbo->toImage();
image2.save("bla4.png");
fbo->release();
delete fbo;
}
3-如何从隐藏的QOpenGLWidget渲染并获取图像
更好的整体解决方案是使用QSurface :: OpenGLSurface类型的自定义QWindow。创建一个额外的QOpenGLContext，一个将要绘制到的额外背景QOpenGLFramebufferObject以及一个QOpenGLShaderProgram，将帧缓冲区混合到后缓冲区。如果要进行多重采样，则可能还需要解析QOpenGLFramebufferObject，才能将多重采样的帧缓冲区转换为非多重采样的帧缓冲区。
类接口可以类似于QOpenGLWidget（对于用户来说，是虚拟的initializeGL（），resizeGL（），paintGL（））。重新实现ExposureEvent（），resizeEvent（）和event（）（您可能还需要重新实现metric（））。
半完整的实现：
标头：
#pragma once
#include <QtCore/QObject>
#include <QtGui/QScreen>
#include <QtGui/QWindow>
#include <QtGui/QPaintEvent>
#include <QtGui/QResizeEvent>
#include <QtGui/QOpenGLPaintDevice>
#include <QtGui/QOpenGLFunctions>
#include <QtGui/QOpenGLFunctions_3_0>
#include <QtGui/QOpenGLFramebufferObject>
#include <QtGui/QSurfaceFormat>
#include <QtWidgets/QWidget>
#include <atomic>
#include <mutex>
class MyGLWindow : public QWindow
{
Q_OBJECT
public:
/// @brief Constructor. Creates a render window.
/// @param targetScreen Target screen.
/// this is because before the FBO and off-screen surface haven't been created.
/// By default this uses the QWindow::requestedFormat() for OpenGL context and off-screen surface.
explicit MyGLWindow(QScreen * targetScreen = nullptr);
/// @brief Constructor. Creates a render window.
/// @param parent Parent window.
/// this is because before the FBO and off-screen surface haven't been created.
/// By default this uses the QWindow::requestedFormat() for OpenGL context and off-screen surface.
explicit MyGLWindow(QWindow * parent);
/// @brief Destructor.
virtual ~MyGLWindow();
/// @brief Create a container widget for this window.
/// @param parent Parent widget.
/// @return Returns a container widget for the window.
QWidget * createWidget(QWidget * parent = nullptr);
/// @brief Check if the window is initialized and can be used for rendering.
/// @return Returns true if context, surface and FBO have been set up to start rendering.
bool isValid() const;
/// @brief Return the context used in this window.
/// @return The context used in this window or nullptr if it hasn't been created yet.
QOpenGLContext * context() const;
/// @brief Return the OpenGL function object that can be used the issue OpenGL commands.
/// @return The functions for the context or nullptr if it the context hasn't been created yet.
QOpenGLFunctions * functions() const;
/// @brief Return the OpenGL off-screen frame buffer object identifier.
/// @return The OpenGL off-screen frame buffer object identifier or 0 if no FBO has been created yet.
/// @note This changes on every resize!
GLuint framebufferObjectHandle() const;
/// @brief Return the OpenGL off-screen frame buffer object.
/// @return The OpenGL off-screen frame buffer object or nullptr if no FBO has been created yet.
/// @note This changes on every resize!
const QOpenGLFramebufferObject * getFramebufferObject() const;
/// @brief Return the OpenGL off-screen frame buffer object identifier.
/// @return The OpenGL off-screen frame buffer object identifier or 0 if no FBO has been created yet.
void bindFramebufferObject();
/// @brief Return the current contents of the FBO.
/// @return FBO content as 32bit QImage. You might need to swap RGBA to BGRA or vice-versa.
QImage grabFramebuffer();
/// @brief Makes the OpenGL context current for rendering.
/// @note Make sure to bindFramebufferObject() if you want to render to this widgets FBO.
void makeCurrent();
/// @brief Release the OpenGL context.
void doneCurrent();
/// @brief Copy content of framebuffer to back buffer and swap buffers if the surface is double-buffered.
/// If the surface is not double-buffered, the frame buffer content is blitted to the front buffer.
/// If the window is not exposed, only the OpenGL pipeline is glFlush()ed so the framebuffer can be read back.
void swapBuffers();
public slots:
/// @brief Lazy update routine like QWidget::update().
void update();
/// @brief Immediately render the widget contents to framebuffer.
void render();
signals:
/// @brief Emitted when swapBuffers() was called and bufferswapping is done.
void frameSwapped();
/// @brief Emitted after a resizeEvent().
void resized();
protected:
virtual void exposeEvent(QExposeEvent *e) override;
virtual void resizeEvent(QResizeEvent *e) override;
virtual bool event(QEvent *e) override;
// virtual int metric(QPaintDevice::PaintDeviceMetric metric) const override;
/// @brief Called exactly once when the window is first exposed OR render() is called when the widget is invisible.
/// @note After this the off-screen surface and FBO are available.
virtual void initializeGL() = 0;
/// @brief Called whenever the window size changes.
/// @param width New window width.
/// @param height New window height.
virtual void resizeGL(int width, int height) = 0;
/// @brief Called whenever the window needs to repaint itself. Override to draw OpenGL content.
/// When this function is called, the context is already current and the correct framebuffer is bound.
virtual void paintGL() = 0;
// /// @brief Called whenever the window needs to repaint itself. Override to draw QPainter content.
// /// @brief This is called AFTER paintGL()! Only needed when painting using a QPainter.
// virtual void paintEvent(QPainter & painter) = 0;
private:
Q_DISABLE_COPY(QGLWindow)
/// @brief Initialize the window.
void initializeInternal();
/// @brief Internal method that does the actual swap work, NOT using a mutex.
void swapBuffersInternal();
/// @brief Internal method that checks state and makes the context current, NOT using a mutex.
void makeCurrentInternal();
/// @brief Internal method to grab content of a specific framebuffer.
QImage grabFramebufferInternal(QOpenGLFramebufferObject * fbo);
/// @brief (Re-)allocate FBO and paint device if needed due to size changes etc.
void recreateFBOAndPaintDevice();
/// @brief False before the window was first exposed OR render() was called.
std::atomic_bool m_initialized;
/// @brief False before the overridden initializeGL() was first called.
bool m_initializedGL = false;
/// @brief True when currently a window update is pending.
std::atomic_bool m_updatePending;
/// @brief Mutex making sure not grabbing while drawing etc.
std::mutex m_mutex;
/// @brief OpenGL render context.
QOpenGLContext * m_context = nullptr;
/// @brief The OpenGL 2.1 / ES 2.0 function object that can be used the issue OpenGL commands.
QOpenGLFunctions * m_functions = nullptr;
/// @brief The OpenGL 3.0 function object that can be used the issue OpenGL commands.
QOpenGLFunctions_3_0 * m_functions_3_0 = nullptr;
/// @brief OpenGL paint device for painting with a QPainter.
QOpenGLPaintDevice * m_paintDevice = nullptr;
/// @brief Background FBO for off-screen rendering when the window is not exposed.
QOpenGLFramebufferObject * m_fbo = nullptr;
/// @brief Background FBO resolving a multi sampling frame buffer in m_fbo to a frame buffer
/// that can be grabbed to a QImage.
QOpenGLFramebufferObject * m_resolvedFbo = nullptr;
/// @brief Shader used for blitting m_fbo to screen if glBlitFrameBuffer is not available.
QOpenGLShaderProgram * m_blitShader;
};
资源：
#include "MyGLWindow.h"
#include <QtCore/QCoreApplication>
#include <QtGui/QPainter>
MyGLWindow::MyGLWindow(QScreen * targetScreen)
: QWindow(targetScreen)
{
//Set Qt::Widget flag to make sure the window resizes properly the first time
//when used as a widget via MyGLWindow::createWidget()!
setFlags(Qt::Widget);
setSurfaceType(QSurface::OpenGLSurface);
setFormat(QGLInfo::DefaultSurfaceFormat());
m_initialized = false;
m_updatePending = false;
create();
initializeInternal();
}
MyGLWindow::MyGLWindow(QWindow * parent)
: QWindow(parent)
{
//Set Qt::Widget flag to make sure the window resizes properly the first time
//when used as a widget via MyGLWindow::createWidget()!
setFlags(Qt::Widget);
setSurfaceType(QSurface::OpenGLSurface);
setFormat(QGLInfo::DefaultSurfaceFormat());
m_initialized = false;
m_updatePending = false;
create();
initializeInternal();
}
MyGLWindow::~MyGLWindow()
{
//to delete the FBOs we first need to make the context current
m_context->makeCurrent(this);
//destroy framebuffer objects
if (m_fbo)
{
m_fbo->release();
delete m_fbo;
m_fbo = nullptr;
}
if (m_resolvedFbo)
{
m_resolvedFbo->release();
delete m_resolvedFbo;
m_resolvedFbo = nullptr;
}
//destroy shader
delete m_blitShader;
m_blitShader = nullptr;
//free context
m_context->doneCurrent();
delete m_context;
m_context = nullptr;
//free paint device
delete m_paintDevice;
m_paintDevice = nullptr;
m_initialized = false;
m_updatePending = false;
}
QWidget * MyGLWindow::createWidget(QWidget * parent)
{
QWidget * container = QWidget::createWindowContainer(this, parent);
return container;
}
QOpenGLContext * MyGLWindow::context() const
{
return m_context;
}
QOpenGLFunctions * MyGLWindow::functions() const
{
return m_functions;
}
GLuint MyGLWindow::framebufferObjectHandle() const
{
return m_fbo ? m_fbo->handle() : 0;
}
const QOpenGLFramebufferObject * MyGLWindow::getFramebufferObject() const
{
return m_fbo;
}
void MyGLWindow::bindFramebufferObject()
{
if (m_fbo)
{
m_fbo->bind();
}
else
{
QOpenGLFramebufferObject::bindDefault();
}
}
bool MyGLWindow::isValid() const
{
return (m_initialized && m_context && m_fbo);
}
void MyGLWindow::makeCurrent()
{
makeCurrentInternal();
}
void MyGLWindow::makeCurrentInternal()
{
if (isValid())
{
m_context->makeCurrent(this);
}
else
{
throw("MyGLWindow::makeCurrent() - Window not yet properly initialized!");
}
}
void MyGLWindow::doneCurrent()
{
if (m_context)
{
m_context->doneCurrent();
}
}
QImage MyGLWindow::grabFramebuffer()
{
std::lock_guard<std::mutex> locker(m_mutex);
makeCurrentInternal();
//blit framebuffer to resolve framebuffer first if needed
if (m_fbo->format().samples() > 0)
{
//check if we have glFrameBufferBlit support. this is true for desktop OpenGL 3.0+, but not OpenGL ES 2.0
if (m_functions_3_0)
{
//only blit the color buffer attachment
m_functions_3_0->glBindFramebuffer(GL_READ_FRAMEBUFFER, m_fbo->handle());
m_functions_3_0->glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_resolvedFbo->handle());
m_functions_3_0->glBlitFramebuffer(0, 0, width(), height(), 0, 0, width(), height(),
GL_COLOR_BUFFER_BIT,
GL_NEAREST);
m_functions_3_0->glBindFramebuffer(GL_FRAMEBUFFER, 0);
}
else
{
//we must unbind the FBO here, so we can use its texture and bind the default back-buffer
m_functions->glBindFramebuffer(GL_FRAMEBUFFER, m_resolvedFbo->handle());
//now use its texture for drawing in the shader
--> bind shader and draw textured quad here
//bind regular FBO again
m_functions->glBindFramebuffer(GL_FRAMEBUFFER, m_fbo->handle());
}
//check if OpenGL errors happened
if (GLenum error = m_functions->glGetError() != GL_NO_ERROR)
{
qDebug() << "MyGLWindow::grabFramebuffer() - OpenGL error" << error;
}
//now grab from resolve FBO
return grabFramebufferInternal(m_resolvedFbo);
}
else
{
//no multi-sampling. grab directly from FBO
return grabFramebufferInternal(m_fbo);
}
}
QImage MyGLWindow::grabFramebufferInternal(QOpenGLFramebufferObject * fbo)
{
QImage image;
//bind framebuffer first
m_functions->glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo->handle());
if (m_functions_3_0)
{
m_functions_3_0->glReadBuffer(GL_COLOR_ATTACHMENT0);
}
GLenum internalFormat = fbo->format().internalTextureFormat();
bool hasAlpha = internalFormat == GL_RGBA || internalFormat == GL_BGRA || internalFormat == GL_RGBA8;
if (internalFormat == GL_BGRA)
{
image = QImage(fbo->size(), hasAlpha ? QImage::Format_ARGB32 : QImage::Format_RGB32);
m_functions->glReadPixels(0, 0, fbo->size().width(), fbo->size().height(), GL_BGRA, GL_UNSIGNED_BYTE, image.bits());
}
else if (internalFormat == GL_RGBA || internalFormat == GL_RGBA8)
{
image = QImage(fbo->size(), hasAlpha ? QImage::Format_RGBA8888 : QImage::Format_RGBX8888);
m_functions->glReadPixels(0, 0, fbo->size().width(), fbo->size().height(), GL_RGBA, GL_UNSIGNED_BYTE, image.bits());
}
else
{
qDebug() << "MyGLWindow::grabFramebuffer() - Unsupported framebuffer format" << internalFormat << "!";
}
m_functions->glBindFramebuffer(GL_FRAMEBUFFER, m_fbo->handle());
return image.mirrored();
}
void MyGLWindow::swapBuffers()
{
swapBuffersInternal();
emit frameSwapped();
}
void MyGLWindow::swapBuffersInternal()
{
if (isExposed() && isVisible())
{
//blit framebuffer to back buffer
m_context->makeCurrent(this);
//make sure all paint operation have been processed
m_functions->glFlush();
//check if we have glFrameBufferBlit support. this is true for desktop OpenGL 3.0+, but not OpenGL ES 2.0
if (m_functions_3_0)
{
//if our framebuffer has multi-sampling, the resolve should be done automagically
m_functions_3_0->glBindFramebuffer(GL_READ_FRAMEBUFFER, m_fbo->handle());
m_functions_3_0->glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
//blit all buffers including depth buffer for further rendering
m_functions_3_0->glBlitFramebuffer(0, 0, width(), height(), 0, 0, width(), height(),
GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT,
GL_NEAREST);
m_functions_3_0->glBindFramebuffer(GL_FRAMEBUFFER, m_fbo->handle());
}
else
{
//we must unbind the FBO here, so we can use its texture and bind the default back-buffer
m_functions->glBindFramebuffer(GL_FRAMEBUFFER, 0);
//now use its texture for drawing in the shader
--> bind shader and draw textured quad here
//bind regular FBO again
m_functions->glBindFramebuffer(GL_FRAMEBUFFER, m_fbo->handle());
}
//check if OpenGL errors happened
if (GLenum error = m_functions->glGetError() != GL_NO_ERROR)
{
qDebug() << "MyGLWindow::swapBuffersInternal() - OpenGL error" << error;
}
//now swap back buffer to front buffer
m_context->swapBuffers(this);
}
else
{
//not visible. only flush the pipeline so we can possibly grab the FBO later
m_context->makeCurrent(this);
m_functions->glFlush();
}
}
void MyGLWindow::recreateFBOAndPaintDevice()
{
const QSize deviceSize = size() * devicePixelRatio();
if (m_context && (m_fbo == nullptr || m_fbo->size() != deviceSize))
{
m_context->makeCurrent(this);
//free old FBOs
if (m_fbo)
{
m_fbo->release();
delete m_fbo;
m_fbo = nullptr;
}
if (m_resolvedFbo)
{
m_resolvedFbo->release();
delete m_resolvedFbo;
m_resolvedFbo = nullptr;
}
//create new frame buffer
QOpenGLFramebufferObjectFormat format = QGLInfo::DefaultFramebufferFormat();
format.setSamples(QGLInfo::HasMultisamplingSupport(m_context) ? 4 : 0);
m_fbo = new QOpenGLFramebufferObject(deviceSize, format);
if (!m_fbo->isValid())
{
throw("MyGLWindow::recreateFbo() - Failed to create background FBO!");
}
//clear framebuffer
m_fbo->bind();
m_functions->glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
m_fbo->release();
//if multi sampling is requested and supported we need a resolve FBO
if (format.samples() > 0)
{
//create resolve framebuffer with only a color attachment
format.setAttachment(QOpenGLFramebufferObject::NoAttachment);
format.setSamples(0);
m_resolvedFbo = new QOpenGLFramebufferObject(deviceSize, format);
if (!m_resolvedFbo->isValid())
{
throw("MyGLWindow::recreateFbo() - Failed to create resolve FBO!");
}
//clear resolve framebuffer
m_resolvedFbo->bind();
m_functions->glClear(GL_COLOR_BUFFER_BIT);
m_resolvedFbo->release();
}
}
//create paint device for painting with QPainter if needed
if (!m_paintDevice)
{
m_paintDevice = new QOpenGLPaintDevice;
}
//update paint device size if needed
if (m_paintDevice->size() != deviceSize)
{
m_paintDevice->setDevicePixelRatio(devicePixelRatio());
m_paintDevice->setSize(deviceSize);
}
}
void MyGLWindow::initializeInternal()
{
if (!m_initialized.exchange(true))
{
//create OpenGL context. we set the format requested by the user (default: QWindow::requestedFormat())
m_context = new QOpenGLContext(this);
m_context->setFormat(format());
if (m_context->create())
{
m_context->makeCurrent(this);
//initialize the OpenGL 2.1 / ES 2.0 functions for this object
m_functions = m_context->functions();
m_functions->initializeOpenGLFunctions();
//try initializing the OpenGL 3.0 functions for this object
m_functions_3_0 = m_context->versionFunctions<QOpenGLFunctions_3_0>();
if (m_functions_3_0)
{
m_functions_3_0->initializeOpenGLFunctions();
}
else
{
//if we do not have OpenGL 3.0 functions, glBlitFrameBuffer is not available, so we must do the blit
//using a shader and the framebuffer texture, so we need to create the shader here...
--> allocate m_blitShader, a simple shader for drawing a textured quad
--> build quad geometry, VBO, whatever
}
//now we have a context, create the FBO
recreateFBOAndPaintDevice();
}
else
{
m_initialized = false;
delete m_context;
m_context = nullptr;
throw("Failed to create OpenGL context!");
}
}
}
void MyGLWindow::update()
{
//only queue an update if there's not already an update pending
if (!m_updatePending.exchange(true))
{
QCoreApplication::postEvent(this, new QEvent(QEvent::UpdateRequest));
}
}
void MyGLWindow::render()
{
std::lock_guard<std::mutex> locker(m_mutex);
//check if we need to initialize stuff
initializeInternal();
//check if we need to call the user initialization
if (!m_initializedGL)
{
m_initializedGL = true;
initializeGL();
}
//make context current and bind framebuffer
makeCurrent();
bindFramebufferObject();
//call user paint function
paintGL();
doneCurrent();
//mark that we're done with updating
m_updatePending = false;
}
void MyGLWindow::exposeEvent(QExposeEvent * e)
{
//call base implementation
QWindow::exposeEvent(e);
//render window content if window is exposed
if (isExposed()/* && isVisible()*/)
{
render();
}
}
void MyGLWindow::resizeEvent(QResizeEvent *e)
{
//call base implementation
QWindow::resizeEvent(e);
m_mutex.lock();
//make context current first
makeCurrent();
//update FBO and paint device
recreateFBOAndPaintDevice();
m_mutex.unlock();
//call user-defined resize method
resizeGL(e->size().width(), e->size().height());
emit resized();
}
bool MyGLWindow::event(QEvent *event)
{
switch (event->type())
{
case QEvent::UpdateLater:
update();
return true;
case QEvent::UpdateRequest:
render();
return true;
default:
return QWindow::event(event);
}
}