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CopperSpice API
1.7.4
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The QOpenGLWidget class is a widget for rendering OpenGL graphics. More...
Public Signals | |
void | aboutToCompose () |
void | aboutToResize () |
void | frameSwapped () |
void | resized () |
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void | customContextMenuRequested (const QPoint &pos) |
void | windowIconChanged (const QIcon &icon) |
void | windowIconTextChanged (const QString &iconText) |
void | windowTitleChanged (const QString &title) |
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void | destroyed (QObject *obj=nullptr) |
void | objectNameChanged (const QString &objectName) |
Public Methods | |
~QOpenGLWidget () | |
QImage | grabFramebuffer () |
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QWidget (QWidget *parent=nullptr, Qt::WindowFlags flags=Qt::EmptyFlag) | |
~QWidget () | |
bool | acceptDrops () const |
QString | accessibleDescription () const |
QString | accessibleName () const |
QList< QAction * > | actions () const |
void | activateWindow () |
void | addAction (QAction *action) |
void | addActions (const QList< QAction * > &actions) |
void | adjustSize () |
bool | autoFillBackground () const |
QPalette::ColorRole | backgroundRole () const |
QBackingStore * | backingStore () const |
QSize | baseSize () const |
QWidget * | childAt (const QPoint &position) const |
QWidget * | childAt (int x, int y) const |
QRect | childrenRect () const |
QRegion | childrenRegion () const |
void | clearFocus () |
void | clearMask () |
QMargins | contentsMargins () const |
QRect | contentsRect () const |
Qt::ContextMenuPolicy | contextMenuPolicy () const |
QCursor | cursor () const |
WId | effectiveWinId () const |
void | ensurePolished () const |
Qt::FocusPolicy | focusPolicy () const |
QWidget * | focusProxy () const |
QWidget * | focusWidget () const |
const QFont & | font () const |
QFontInfo | fontInfo () const |
QFontMetrics | fontMetrics () const |
QPalette::ColorRole | foregroundRole () const |
QRect | frameGeometry () const |
QSize | frameSize () const |
const QRect & | geometry () const |
void | getContentsMargins (int *left, int *top, int *right, int *bottom) const |
QPixmap | grab (const QRect &rectangle=QRect (QPoint (0, 0), QSize (-1,-1))) |
void | grabGesture (Qt::GestureType gestureType, Qt::GestureFlags flags=Qt::GestureFlags ()) |
void | grabKeyboard () |
void | grabMouse () |
void | grabMouse (const QCursor &cursor) |
int | grabShortcut (const QKeySequence &key, Qt::ShortcutContext context=Qt::WindowShortcut) |
QGraphicsEffect * | graphicsEffect () const |
QGraphicsProxyWidget * | graphicsProxyWidget () const |
bool | hasEditFocus () const |
bool | hasFocus () const |
virtual bool | hasHeightForWidth () const |
bool | hasMouseTracking () const |
int | height () const |
virtual int | heightForWidth (int width) const |
Qt::InputMethodHints | inputMethodHints () const |
virtual QVariant | inputMethodQuery (Qt::InputMethodQuery query) const |
void | insertAction (QAction *before, QAction *action) |
void | insertActions (QAction *before, QList< QAction * > actions) |
bool | isActiveWindow () const |
bool | isAncestorOf (const QWidget *child) const |
bool | isEnabled () const |
bool | isEnabledTo (const QWidget *parent) const |
bool | isEnabledToTLW () const |
bool | isFullScreen () const |
bool | isHidden () const |
bool | isMaximized () const |
bool | isMinimized () const |
bool | isModal () const |
bool | isTopLevel () const |
bool | isVisible () const |
bool | isVisibleTo (const QWidget *parent) const |
bool | isWindow () const |
bool | isWindowModified () const |
QLayout * | layout () const |
Qt::LayoutDirection | layoutDirection () const |
QLocale | locale () const |
QPoint | mapFrom (const QWidget *parent, const QPoint &pos) const |
QPoint | mapFromGlobal (const QPoint &pos) const |
QPoint | mapFromParent (const QPoint &pos) const |
QPoint | mapTo (const QWidget *parent, const QPoint &pos) const |
QPoint | mapToGlobal (const QPoint &pos) const |
QPoint | mapToParent (const QPoint &pos) const |
QRegion | mask () const |
int | maximumHeight () const |
QSize | maximumSize () const |
int | maximumWidth () const |
int | minimumHeight () const |
QSize | minimumSize () const |
virtual QSize | minimumSizeHint () const |
int | minimumWidth () const |
void | move (const QPoint &point) |
void | move (int x, int y) |
QWidget * | nativeParentWidget () const |
QWidget * | nextInFocusChain () const |
QRect | normalGeometry () const |
void | overrideWindowFlags (Qt::WindowFlags flags) |
QPaintEngine * | paintEngine () const override |
const QPalette & | palette () const |
QWidget * | parentWidget () const |
QPoint | pos () const |
QWidget * | previousInFocusChain () const |
QRect | rect () const |
void | releaseKeyboard () |
void | releaseMouse () |
void | releaseShortcut (int id) |
void | removeAction (QAction *action) |
void | render (QPaintDevice *target, const QPoint &targetOffset=QPoint (), const QRegion &sourceRegion=QRegion (), RenderFlags renderFlags=RenderFlags (DrawWindowBackground|DrawChildren)) |
void | render (QPainter *painter, const QPoint &targetOffset=QPoint (), const QRegion &sourceRegion=QRegion (), RenderFlags renderFlags=RenderFlags (DrawWindowBackground|DrawChildren)) |
void | repaint (const QRect &rect) |
void | repaint (const QRegion ®ion) |
void | repaint (int x, int y, int w, int h) |
void | resize (const QSize &size) |
void | resize (int w, int h) |
bool | restoreGeometry (const QByteArray &geometry) |
QByteArray | saveGeometry () const |
void | scroll (int dx, int dy) |
void | scroll (int dx, int dy, const QRect &rect) |
void | setAcceptDrops (bool on) |
void | setAccessibleDescription (const QString &description) |
void | setAccessibleName (const QString &name) |
void | setAttribute (Qt::WidgetAttribute attribute, bool enable=true) |
void | setAutoFillBackground (bool enable) |
void | setBackgroundRole (QPalette::ColorRole role) |
void | setBaseSize (const QSize &size) |
void | setBaseSize (int basew, int baseh) |
void | setContentsMargins (const QMargins &margins) |
void | setContentsMargins (int left, int top, int right, int bottom) |
void | setContextMenuPolicy (Qt::ContextMenuPolicy policy) |
void | setCursor (const QCursor &cursor) |
void | setEditFocus (bool enable) |
void | setFixedHeight (int h) |
void | setFixedSize (const QSize &size) |
void | setFixedSize (int w, int h) |
void | setFixedWidth (int w) |
void | setFocus (Qt::FocusReason reason) |
void | setFocusPolicy (Qt::FocusPolicy policy) |
void | setFocusProxy (QWidget *widget) |
void | setFont (const QFont &font) |
void | setForegroundRole (QPalette::ColorRole role) |
void | setGeometry (const QRect &rect) |
void | setGeometry (int x, int y, int w, int h) |
void | setGraphicsEffect (QGraphicsEffect *effect) |
void | setInputMethodHints (Qt::InputMethodHints hints) |
void | setLayout (QLayout *layout) |
void | setLayoutDirection (Qt::LayoutDirection direction) |
void | setLocale (const QLocale &locale) |
void | setMask (const QBitmap &bitmap) |
void | setMask (const QRegion ®ion) |
void | setMaximumHeight (int maxh) |
void | setMaximumSize (const QSize &size) |
void | setMaximumSize (int maxw, int maxh) |
void | setMaximumWidth (int maxw) |
void | setMinimumHeight (int minh) |
void | setMinimumSize (const QSize &size) |
void | setMinimumSize (int minw, int minh) |
void | setMinimumWidth (int minw) |
void | setMouseTracking (bool enable) |
void | setPalette (const QPalette &palette) |
void | setParent (QWidget *parent) |
void | setParent (QWidget *parent, Qt::WindowFlags flags) |
void | setShortcutAutoRepeat (int id, bool enable=true) |
void | setShortcutEnabled (int id, bool enable=true) |
void | setSizeIncrement (const QSize &size) |
void | setSizeIncrement (int w, int h) |
void | setSizePolicy (QSizePolicy policy) |
void | setSizePolicy (QSizePolicy::Policy horizontal, QSizePolicy::Policy vertical) |
void | setStatusTip (const QString &data) |
void | setStyle (QStyle *style) |
void | setToolTip (const QString &data) |
void | setToolTipDuration (int msec) |
void | setUpdatesEnabled (bool enable) |
void | setWhatsThis (const QString &str) |
void | setWindowFilePath (const QString &filePath) |
void | setWindowFlags (Qt::WindowFlags flags) |
void | setWindowIcon (const QIcon &icon) |
void | setWindowModality (Qt::WindowModality windowModality) |
void | setWindowOpacity (qreal level) |
void | setWindowRole (const QString &role) |
void | setWindowState (Qt::WindowStates windowState) |
QSize | size () const |
virtual QSize | sizeHint () const |
QSize | sizeIncrement () const |
QSizePolicy | sizePolicy () const |
void | stackUnder (QWidget *widget) |
QString | statusTip () const |
QStyle * | style () const |
QString | styleSheet () const |
bool | testAttribute (Qt::WidgetAttribute attribute) const |
QString | toolTip () const |
int | toolTipDuration () const |
QWidget * | topLevelWidget () const |
bool | underMouse () const |
void | ungrabGesture (Qt::GestureType gestureType) |
void | unsetCursor () |
void | unsetLayoutDirection () |
void | unsetLocale () |
void | update (const QRect &rect) |
void | update (const QRegion ®ion) |
void | update (int x, int y, int w, int h) |
void | updateGeometry () |
bool | updatesEnabled () const |
QRegion | visibleRegion () const |
QString | whatsThis () const |
int | width () const |
QWidget * | window () const |
QString | windowFilePath () const |
Qt::WindowFlags | windowFlags () const |
QWindow * | windowHandle () const |
QIcon | windowIcon () const |
Qt::WindowModality | windowModality () const |
qreal | windowOpacity () const |
QString | windowRole () const |
Qt::WindowStates | windowState () const |
QString | windowTitle () const |
Qt::WindowType | windowType () const |
WId | winId () const |
int | x () const |
int | y () const |
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QObject (QObject *parent=nullptr) | |
~QObject () | |
bool | blockSignals (bool block) |
const QList< QObject * > & | children () const |
bool | connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection) |
bool | connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection) |
bool | disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const |
bool | disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const |
bool | disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const |
void | dumpObjectInfo () |
void | dumpObjectTree () |
QList< QString > | dynamicPropertyNames () const |
virtual bool | event (QEvent *event) |
virtual bool | eventFilter (QObject *watched, QEvent *event) |
template<typename T > | |
T | findChild (const QString &childName=QString ()) const |
template<class T > | |
QList< T > | findChildren (const QRegularExpression ®Exp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const |
template<class T > | |
QList< T > | findChildren (const QString &childName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const |
bool | inherits (const QString &className) const |
void | installEventFilter (QObject *filterObj) |
bool | isWidgetType () const |
bool | isWindowType () const |
void | killTimer (int id) |
const QMetaObject * | metaObject () const |
void | moveToThread (QThread *targetThread) |
QString | objectName () const |
QObject * | parent () const |
template<class T = QVariant> | |
T | property (const QString &name) const |
void | removeEventFilter (QObject *obj) |
void | setObjectName (const QString &name) |
void | setParent (QObject *parent) |
bool | setProperty (const QString &name, const QVariant &value) |
bool | signalsBlocked () const |
int | startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer) |
QThread * | thread () const |
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virtual | ~QPaintDevice () |
int | colorCount () const |
int | depth () const |
int | devicePixelRatio () const |
qreal | devicePixelRatioF () const |
int | height () const |
int | heightMM () const |
int | logicalDpiX () const |
int | logicalDpiY () const |
bool | paintingActive () const |
int | physicalDpiX () const |
int | physicalDpiY () const |
int | width () const |
int | widthMM () const |
Protected Methods | |
int | metric (QPaintDevice::PaintDeviceMetric metric) const override |
QPaintEngine * | paintEngine () const override |
void | paintEvent (QPaintEvent *event) override |
void | resizeEvent (QResizeEvent *event) override |
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virtual void | actionEvent (QActionEvent *event) |
virtual void | changeEvent (QEvent *event) |
virtual void | closeEvent (QCloseEvent *event) |
virtual void | contextMenuEvent (QContextMenuEvent *event) |
void | create (WId window=0, bool initializeWindow=true, bool destroyOldWindow=true) |
void | destroy (bool destroyWindow=true, bool destroySubWindows=true) |
virtual void | dragEnterEvent (QDragEnterEvent *event) |
virtual void | dragLeaveEvent (QDragLeaveEvent *event) |
virtual void | dragMoveEvent (QDragMoveEvent *event) |
virtual void | dropEvent (QDropEvent *event) |
virtual void | enterEvent (QEvent *event) |
bool | event (QEvent *event) override |
virtual void | focusInEvent (QFocusEvent *event) |
bool | focusNextChild () |
virtual bool | focusNextPrevChild (bool next) |
virtual void | focusOutEvent (QFocusEvent *event) |
bool | focusPreviousChild () |
virtual void | hideEvent (QHideEvent *event) |
void | initPainter (QPainter *painter) const override |
virtual void | inputMethodEvent (QInputMethodEvent *event) |
virtual void | keyPressEvent (QKeyEvent *event) |
virtual void | keyReleaseEvent (QKeyEvent *event) |
virtual void | leaveEvent (QEvent *event) |
int | metric (PaintDeviceMetric metric) const override |
virtual void | mouseDoubleClickEvent (QMouseEvent *event) |
virtual void | mouseMoveEvent (QMouseEvent *event) |
virtual void | mousePressEvent (QMouseEvent *event) |
virtual void | mouseReleaseEvent (QMouseEvent *event) |
virtual void | moveEvent (QMoveEvent *event) |
virtual bool | nativeEvent (const QByteArray &eventType, void *message, long *result) |
virtual void | showEvent (QShowEvent *event) |
virtual void | tabletEvent (QTabletEvent *event) |
virtual void | wheelEvent (QWheelEvent *event) |
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virtual void | childEvent (QChildEvent *event) |
virtual void | connectNotify (const QMetaMethod &signalMethod) const |
virtual void | customEvent (QEvent *event) |
virtual void | disconnectNotify (const QMetaMethod &signalMethod) const |
bool | isSignalConnected (const QMetaMethod &signalMethod) const |
int | receivers (const QString &signal) const |
QObject * | sender () const |
int | senderSignalIndex () const |
virtual void | timerEvent (QTimerEvent *event) |
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QPaintDevice () | |
Additional Inherited Members | |
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enum | RenderFlag |
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enum | PaintDeviceMetric |
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bool | close () |
void | hide () |
void | lower () |
void | raise () |
void | repaint () |
void | setDisabled (bool disable) |
void | setEnabled (bool enable) |
void | setFocus () |
void | setHidden (bool hidden) |
void | setStyleSheet (const QString &styleSheet) |
virtual void | setVisible (bool visible) |
void | setWindowModified (bool modified) |
void | setWindowTitle (const QString &title) |
void | show () |
void | showFullScreen () |
void | showMaximized () |
void | showMinimized () |
void | showNormal () |
void | update () |
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void | deleteLater () |
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static QWidget * | createWindowContainer (QWindow *window, QWidget *parent=nullptr, Qt::WindowFlags flags=Qt::EmptyFlag) |
static QWidget * | find (WId id) |
static QWidget * | keyboardGrabber () |
static QWidget * | mouseGrabber () |
static void | setTabOrder (QWidget *firstWidget, QWidget *secondWidget) |
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static bool | connect (const QObject *sender, const QMetaMethod &signalMethod, const QObject *receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection) |
static bool | connect (const QObject *sender, const QString &signalMethod, const QObject *receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ()) |
static bool | connect (const QObject *sender, const QString &signalMethod, const QString &location, const QObject *receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection) |
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn > | |
static bool | connect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, SlotReturn (SlotClass::*slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection) |
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T > | |
static bool | connect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection) |
static bool | disconnect (const QObject *sender, const QMetaMethod &signalMethod, const QObject *receiver, const QMetaMethod &slotMethod) |
static bool | disconnect (const QObject *sender, const QString &signalMethod, const QObject *receiver, const QString &slotMethod) |
static bool | disconnect (const QObject *sender, const QString &signalMethod, const QString &location, const QObject *receiver, const QString &slotMethod) |
static bool | disconnect (const QObject *sender, std::nullptr_t, const QObject *receiver, std::nullptr_t) |
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn > | |
static bool | disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, SlotReturn (SlotClass::*slotMethod)(SlotArgs...)) |
template<class Sender , class SignalClass , class... SignalArgs, class Receiver > | |
static bool | disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr) |
template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T > | |
static bool | disconnect (const Sender *sender, void (SignalClass::*signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod) |
static QMetaObject & | staticMetaObject () |
static QString | tr (const char *text, const char *comment=nullptr, std::optional< int > numArg=std::optional< int >()) |
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void | updateMicroFocus () |
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acceptDrops | |
accessibleDescription | |
accessibleName | |
autoFillBackground | |
baseSize | |
childrenRect | |
childrenRegion | |
contextMenuPolicy | |
cursor | |
enabled | |
focus | |
focusPolicy | |
font | |
frameGeometry | |
frameSize | |
fullScreen | |
geometry | |
height | |
inputMethodHints | |
isActiveWindow | |
layoutDirection | |
locale | |
maximized | |
maximumHeight | |
maximumSize | |
maximumWidth | |
minimized | |
minimumHeight | |
minimumSize | |
minimumSizeHint | |
minimumWidth | |
modal | |
mouseTracking | |
normalGeometry | |
palette | |
pos | |
rect | |
size | |
sizeHint | |
sizeIncrement | |
sizePolicy | |
statusTip | |
styleSheet | |
toolTip | |
updatesEnabled | |
visible | |
whatsThis | |
width | |
windowFilePath | |
windowFlags | |
windowIcon | |
windowIconText | |
windowModality | |
windowModified | |
windowOpacity | |
windowTitle | |
x | |
y | |
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objectName | |
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QWidgetList | |
WId | |
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T | qobject_cast (QObject *object) |
QObjectList | |
The QOpenGLWidget class is a widget for rendering OpenGL graphics.
QOpenGLWidget provides functionality for displaying OpenGL graphics integrated in a CopperSpice application. It is very simple to use: Make your class inherit from it and use the subclass like any other QWidget, except that you have the choice between using QPainter and standard OpenGL rendering commands.
QOpenGLWidget provides three convenient virtual functions you can reimplement in your subclass to perform the typical OpenGL tasks.
If you need to trigger a repaint from places other than paintGL() (a typical example is when using timers to animate scenes), you should call the widget's update() function to schedule an update.
Your widget's OpenGL rendering context is made current when paintGL(), resizeGL(), or initializeGL() is called. If you need to call the standard OpenGL API functions from other places (e.g. in your widget's constructor or in your own paint functions), you must call makeCurrent() first.
All rendering happens into an OpenGL framebuffer object. makeCurrent() ensure that it is bound in the context. Keep this in mind when creating and binding additional framebuffer objects in the rendering code in paintGL(). Never re-bind the framebuffer with ID 0. Instead, call defaultFramebufferObject() to get the ID that should be bound.
QOpenGLWidget allows using different OpenGL versions and profiles when the platform supports it. Just set the requested format via setFormat(). Keep in mind however that having multiple QOpenGLWidget instances in the same window requires that they all use the same format, or at least formats that do not make the contexts non-sharable. To overcome this issue, prefer using QSurfaceFormat::setDefaultFormat() instead of setFormat().
Note: Calling QSurfaceFormat::setDefaultFormat() before constructing the QApplication instance is mandatory on some platforms (for example, macOS) when an OpenGL core profile context is requested. This is to ensure that resource sharing between contexts stays functional as all internal contexts are created using the correct version and profile.
As described above, subclass QOpenGLWidget to render pure 3D content in the following way.
It is also possible to draw 2D graphics onto a QOpenGLWidget subclass using QPainter.
When performing drawing using QPainter only, it is also possible to perform the painting like it is done for ordinary widgets by reimplementing paintEvent().
When making OpenGL function calls, it is strongly recommended to avoid calling the functions directly. Instead, prefer using QOpenGLFunctions (when making portable applications) or the versioned variants (for example, QOpenGLFunctions_3_2_Core and similar, when targeting modern, desktop-only OpenGL). This way the application will work correctly in all build configurations, including the ones that perform dynamic OpenGL implementation loading which means applications are not directly linking to an GL implementation and thus direct function calls are not feasible.
In paintGL() the current context is always accessible by calling QOpenGLContext::currentContext(). From this context an already initialized, ready-to-be-used QOpenGLFunctions instance is retrievable by calling QOpenGLContext::functions(). An alternative to prefixing every GL call is to inherit from QOpenGLFunctions and call QOpenGLFunctions::initializeOpenGLFunctions() in initializeGL().
As for the OpenGL headers, note that in most cases there will be no need to directly include any headers like GL.h. The OpenGL-related CopperSpice headers will include qopengl.h which will in turn include an appropriate header for the system. This might be an OpenGL ES 3.x or 2.0 header, the highest version that is available, or a system-provided gl.h. In addition, a copy of the extension headers (called glext.h on some systems) is provided as part of CopperSpice both for OpenGL and OpenGL ES. These will get included automatically on platforms where feasible. This means that constants and function pointer typedefs from ARB, EXT, OES extensions are automatically available.
QOpenGLWidget::~QOpenGLWidget | ( | ) |
Destroys the QOpenGLWidget instance, freeing its resources.
The QOpenGLWidget's context is made current in the destructor, allowing for safe destruction of any child object that may need to release OpenGL resources belonging to the context provided by this widget.
If you have objects wrapping OpenGL resources (such as QOpenGLBuffer, QOpenGLShaderProgram, etc.) as members of a OpenGLWidget subclass, you may need to add a call to makeCurrent() in that subclass destructor as well. Due to the rules of C++ object destruction, those objects will be destroyed before calling this function (but after that the destructor of the subclass has run), therefore making the OpenGL context current in this function happens too late for their safe disposal.
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signal |
This signal is emitted when the widget's top-level window is about to begin composing the textures of its QOpenGLWidget children and the other widgets.
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signal |
This signal is emitted when the widget's size is changed and therefore the framebuffer object is going to be recreated.
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signal |
This signal is emitted after the widget's top-level window has finished composition and returned from its potentially blocking QOpenGLContext::swapBuffers() call.
QImage QOpenGLWidget::grabFramebuffer | ( | ) |
Renders and returns a 32-bit RGB image of the framebuffer.
This is a potentially expensive operation because it relies on glReadPixels() to read back the pixels. This may be slow and can stall the GPU pipeline.
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overrideprotectedvirtual |
Returns the metric information for the given paint device metric.
Reimplemented from QPaintDevice::metric()
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overrideprotectedvirtual |
Returns a pointer to the paint engine used for drawing on the device.
Implements QPaintDevice::paintEngine()
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overrideprotectedvirtual |
This event handler can be reimplemented in a subclass to receive paint events passed in event. A paint event is a request to repaint all or part of a widget. It can happen for one of the following reasons.
Many widgets can simply repaint their entire surface when asked to, but some slow widgets need to optimize by painting only the requested region: QPaintEvent::region(). This speed optimization does not change the result, as painting is clipped to that region during event processing. QListView and QTableView do this, for example.
CopperSpice also tries to speed up painting by merging multiple paint events into one. When update() is called several times or the window system sends several paint events, CopperSpice merges these events into one event with a larger region (see QRegion::united()). The repaint() function does not permit this optimization, so we suggest using update() whenever possible.
When the paint event occurs, the update region has normally been erased, so you are painting on the widget's background. The background can be set using setBackgroundRole() and setPalette().
QWidget automatically double-buffers its painting, so there is no need to write double-buffering code in paintEvent() to avoid flicker.
For the X11 platform it is possible to toggle global double buffering by calling qt_x11_set_global_double_buffer()
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Generally you should refrain from calling update() or repaint() inside a paintEvent(). For example, calling update() or repaint() on children inside a paintevent() results in undefined behavior; the child may or may not get a paint event.
Reimplemented from QWidget::paintEvent()
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signal |
This signal is emitted right after the framebuffer object has been recreated due to resizing the widget.
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overrideprotectedvirtual |
This event handler can be reimplemented in a subclass to receive widget resize events which are passed in the event parameter. When resizeEvent() is called, the widget already has its new geometry. The old size is accessible through QResizeEvent::oldSize().
The widget will be erased and receive a paint event immediately after processing the resize event. No drawing need be (or should be) done inside this handler.
Reimplemented from QWidget::resizeEvent()