QGLWidget Class Reference

#include <qgl.h>

Inheritance diagram for QGLWidget:

[legend]Collaboration diagram for QGLWidget:

[legend]List of all members.

---

Detailed Description

The QGLWidget class is a widget for rendering OpenGL graphics.

QGLWidget provides functionality for displaying OpenGL graphics integrated into a Qt application. It is very simple to use. You 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.

QGLWidget provides three convenient virtual functions that you can reimplement in your subclass to perform the typical OpenGL tasks:

paintGL() - Renders the OpenGL scene. Gets called whenever the widget needs to be updated. resizeGL() - Sets up the OpenGL viewport, projection, etc. Gets called whenever the the widget has been resized (and also when it is shown for the first time because all newly created widgets get a resize event automatically). initializeGL() - Sets up the OpenGL rendering context, defines display lists, etc. Gets called once before the first time resizeGL() or paintGL() is called.

Here is a rough outline of how a QGLWidget subclass might look:

    class MyGLDrawer : public QGLWidget
    {
        Q_OBJECT        // must include this if you use Qt signals/slots

    public:
        MyGLDrawer(QWidget *parent)
            : QGLWidget(parent) {}

    protected:

        void initializeGL()
        {
            // Set up the rendering context, define display lists etc.:
            ...
            glClearColor(0.0, 0.0, 0.0, 0.0);
            glEnable(GL_DEPTH_TEST);
            ...
        }

        void resizeGL(int w, int h)
        {
            // setup viewport, projection etc.:
            glViewport(0, 0, (GLint)w, (GLint)h);
            ...
            glFrustum(...);
            ...
        }

        void paintGL()
        {
            // draw the scene:
            ...
            glRotatef(...);
            glMaterialfv(...);
            glBegin(GL_QUADS);
            glVertex3f(...);
            glVertex3f(...);
            ...
            glEnd();
            ...
        }

    };

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 updateGL() function.

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.

QGLWidget provides functions for requesting a new display format and you can also create widgets with customized rendering contexts.

You can also share OpenGL display lists between QGLWidgets (see the documentation of the QGLWidget constructors for details).

The QGLWidget creates a GL overlay context in addition to the normal context if overlays are supported by the underlying system. If you want to use overlays, you specify it in the \link QGLFormat format\endlink. (Note: Overlay must be requested in the format passed to the QGLWidget constructor.) Your GL widget should also implement some or all of these virtual methods: \list \i paintOverlayGL() \i resizeOverlayGL() \i initializeOverlayGL() \endlist These methods work in the same way as the normal paintGL() etc. functions, except that they will be called when the overlay context is made current. You can explicitly make the overlay context current by using makeOverlayCurrent(), and you can access the overlay context directly (e.g. to ask for its transparent color) by calling overlayContext(). On X servers in which the default visual is in an overlay plane, non-GL Qt windows can also be used for overlays. @section Painting Techniques As described above, subclass QGLWidget to render pure 3D content in the following way: \list \o Reimplement the QGLWidget::initializeGL() and QGLWidget::resizeGL() to set up the OpenGL state and provide a perspective transformation. \o Reimplement QGLWidget::paintGL() to paint the 3D scene, calling only OpenGL functions to draw on the widget. \endlist It is also possible to draw 2D graphics onto a QGLWidget subclass, it is necessary to reimplement QGLWidget::paintEvent() and do the following: \list \o Construct a QPainter object. \o Initialize it for use on the widget with the QPainter::begin() function. \o Draw primitives using QPainter's member functions. \o Call QPainter::end() to finish painting. \endlist Overpainting 2D content on top of 3D content takes a little more effort. One approach to doing this is shown in the \l{Overpainting Example}{Overpainting} example. \e{OpenGL is a trademark of Silicon Graphics, Inc. in the United States and other countries.} \sa QGLPixelBuffer, {Hello GL Example}, {2D Painting Example}, {Overpainting Example}, {Grabber Example} Definition at line 307 of file qgl.h.

Public Slots
virtual void	updateGL ()
virtual void	updateOverlayGL ()
Public Member Functions
	QGLWidget (QWidget *parent=0, const QGLWidget *shareWidget=0, Qt::WindowFlags f=0)
	QGLWidget (QGLContext *context, QWidget *parent=0, const QGLWidget *shareWidget=0, Qt::WindowFlags f=0)
	QGLWidget (const QGLFormat &format, QWidget *parent=0, const QGLWidget *shareWidget=0, Qt::WindowFlags f=0)
	~QGLWidget ()
void	qglColor (const QColor &c) const
void	qglClearColor (const QColor &c) const
bool	isValid () const
bool	isSharing () const
void	makeCurrent ()
void	doneCurrent ()
bool	doubleBuffer () const
void	swapBuffers ()
QGLFormat	format () const
void	setFormat (const QGLFormat &format)
const QGLContext *	context () const
void	setContext (QGLContext *context, const QGLContext *shareContext=0, bool deleteOldContext=true)
QPixmap	renderPixmap (int w=0, int h=0, bool useContext=false)
QImage	grabFrameBuffer (bool withAlpha=false)
void	makeOverlayCurrent ()
const QGLContext *	overlayContext () const
void	setMouseTracking (bool enable)
const QGLColormap &	colormap () const
void	setColormap (const QGLColormap &map)
void	renderText (int x, int y, const QString &str, const QFont &fnt=QFont(), int listBase=2000)
void	renderText (double x, double y, double z, const QString &str, const QFont &fnt=QFont(), int listBase=2000)
QPaintEngine *	paintEngine () const
GLuint	bindTexture (const QImage &image, GLenum target=GL_TEXTURE_2D, GLint format=GL_RGBA)
GLuint	bindTexture (const QPixmap &pixmap, GLenum target=GL_TEXTURE_2D, GLint format=GL_RGBA)
GLuint	bindTexture (const QString &fileName)
void	deleteTexture (GLuint tx_id)
Static Public Member Functions
static QImage	convertToGLFormat (const QImage &img)
Protected Member Functions
bool	event (QEvent *)
virtual void	initializeGL ()
virtual void	resizeGL (int w, int h)
virtual void	paintGL ()
virtual void	initializeOverlayGL ()
virtual void	resizeOverlayGL (int w, int h)
virtual void	paintOverlayGL ()
void	setAutoBufferSwap (bool on)
bool	autoBufferSwap () const
void	paintEvent (QPaintEvent *)
void	resizeEvent (QResizeEvent *)
virtual void	glInit ()
virtual void	glDraw ()
int	fontDisplayListBase (const QFont &fnt, int listBase=2000)
Friends
class	QGLDrawable
class	QGLPixelBuffer
class	QGLPixelBufferPrivate
class	QGLContext
class	QGLOverlayWidget
class	QOpenGLPaintEngine

---

Constructor & Destructor Documentation

QGLWidget::QGLWidget	(	QWidget *	parent = 0,
		const QGLWidget *	shareWidget = 0,
		Qt::WindowFlags	f = 0
	)			[explicit]

Constructs an OpenGL widget with a parent widget.

The default format is used. The widget will be invalid if the system has no OpenGL support.

The parent and widget flag, f, arguments are passed to the QWidget constructor.

If the shareWidget parameter points to a valid QGLWidget, this widget will share OpenGL display lists with shareWidget. If this widget and shareWidget have different formats, display list sharing may fail. You can check whether display list sharing succeeded by calling isSharing().

The initialization of OpenGL rendering state, etc. should be done by overriding the initializeGL() function, rather than in the constructor of your QGLWidget subclass.

See also:

QGLFormat::defaultFormat(), {Textures Example}

Definition at line 2372 of file qgl.cpp.

References d, QGLFormat::defaultFormat(), QGLContext, QWidget::setAttribute(), QWidget::setAutoFillBackground(), Qt::WA_NoSystemBackground, and Qt::WA_PaintOnScreen.

    : QWidget(*(new QGLWidgetPrivate), parent, f | Qt::MSWindowsOwnDC)
{
    Q_D(QGLWidget);
    setAttribute(Qt::WA_PaintOnScreen);
    setAttribute(Qt::WA_NoSystemBackground);
    setAutoFillBackground(true); // for compatibility
    d->init(new QGLContext(QGLFormat::defaultFormat(), this), shareWidget);
}

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QGLWidget::QGLWidget	(	QGLContext *	context,
		QWidget *	parent = 0,
		const QGLWidget *	shareWidget = 0,
		Qt::WindowFlags	f = 0
	)			[explicit]

Constructs an OpenGL widget with parent parent.

The context argument is a pointer to the QGLContext that you wish to be bound to this widget. This allows you to pass in your own QGLContext sub-classes.

The widget will be invalid if the system has no OpenGL support.

The parent and widget flag, f, arguments are passed to the QWidget constructor.

If the shareWidget parameter points to a valid QGLWidget, this widget will share OpenGL display lists with shareWidget. If this widget and shareWidget have different formats, display list sharing may fail. You can check whether display list sharing succeeded by calling isSharing().

The initialization of OpenGL rendering state, etc. should be done by overriding the initializeGL() function, rather than in the constructor of your QGLWidget subclass.

See also:

QGLFormat::defaultFormat(), isValid()

Definition at line 2447 of file qgl.cpp.

References context(), d, QWidget::setAttribute(), QWidget::setAutoFillBackground(), Qt::WA_NoSystemBackground, and Qt::WA_PaintOnScreen.

    : QWidget(*(new QGLWidgetPrivate), parent, f | Qt::MSWindowsOwnDC)
{
    Q_D(QGLWidget);
    setAttribute(Qt::WA_PaintOnScreen);
    setAttribute(Qt::WA_NoSystemBackground);
    setAutoFillBackground(true); // for compatibility
    d->init(context, shareWidget);
}

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QGLWidget::QGLWidget	(	const QGLFormat &	format,
		QWidget *	parent = 0,
		const QGLWidget *	shareWidget = 0,
		Qt::WindowFlags	f = 0
	)			[explicit]

Constructs an OpenGL widget with parent parent.

The format argument specifies the desired rendering options . If the underlying OpenGL/Window system cannot satisfy all the features requested in format, the nearest subset of features will be used. After creation, the format() method will return the actual format obtained.

The widget will be invalid if the system has no OpenGL support.

The parent and widget flag, f, arguments are passed to the QWidget constructor.

If the shareWidget parameter points to a valid QGLWidget, this widget will share OpenGL display lists with shareWidget. If this widget and shareWidget have different formats, display list sharing may fail. You can check whether display list sharing succeeded by calling isSharing().

The initialization of OpenGL rendering state, etc. should be done by overriding the initializeGL() function, rather than in the constructor of your QGLWidget subclass.

See also:

QGLFormat::defaultFormat(), isValid()

Definition at line 2411 of file qgl.cpp.

References d, format(), QGLContext, QWidget::setAttribute(), QWidget::setAutoFillBackground(), Qt::WA_NoSystemBackground, and Qt::WA_PaintOnScreen.

    : QWidget(*(new QGLWidgetPrivate), parent, f | Qt::MSWindowsOwnDC)
{
    Q_D(QGLWidget);
    setAttribute(Qt::WA_PaintOnScreen);
    setAttribute(Qt::WA_NoSystemBackground);
    setAutoFillBackground(true); // for compatibility
    d->init(new QGLContext(format, this), shareWidget);
}

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QGLWidget::~QGLWidget

(

)

Destroys the widget.

Definition at line 2462 of file qgl.cpp.

References d, and QWidget::winId().

{
    Q_D(QGLWidget);
#if defined(GLX_MESA_release_buffers) && defined(QGL_USE_MESA_EXT)
    bool doRelease = (glcx && glcx->windowCreated());
#endif
    delete d->glcx;
#if defined(Q_WGL)
    delete d->olcx;
#endif
#ifdef Q_WS_MAC
    delete d->watcher;
    d->watcher = 0;
#endif
#if defined(GLX_MESA_release_buffers) && defined(QGL_USE_MESA_EXT)
    if (doRelease)
        glXReleaseBuffersMESA(x11Display(), winId());
#endif
    d->cleanupColormaps();
}

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---

Member Function Documentation

void QGLWidget::qglColor

(

const QColor &

c

)

const

Convenience function for specifying a drawing color to OpenGL. Calls glColor4 (in RGBA mode) or glIndex (in color-index mode) with the color c. Applies to this widgets GL context.

See also:

qglClearColor(), QGLContext::currentContext(), QColor

Definition at line 3064 of file qgl.cpp.

References c, QGLContext::colorIndex(), QGLContext::currentContext(), d, QGLContext::format(), i, and QGLFormat::rgba().

Referenced by GLWidget::extrude(), and GLWidget::quad().

{
#ifdef Q_WS_QWS
    glColor4f(c.red()/255.0, c.green()/255.0, c.blue()/255.0, c.alpha()/255.0);
#else
    Q_D(const QGLWidget);
    const QGLContext *ctx = QGLContext::currentContext();
    if (ctx) {
        if (ctx->format().rgba())
            glColor4ub(c.red(), c.green(), c.blue(), c.alpha());
        else if (!d->cmap.isEmpty()) { // QGLColormap in use?
            int i = d->cmap.find(c.rgb());
            if (i < 0)
                i = d->cmap.findNearest(c.rgb());
            glIndexi(i);
        } else
            glIndexi(ctx->colorIndex(c));
    }
#endif
}

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void QGLWidget::qglClearColor

(

const QColor &

c

)

const

Convenience function for specifying the clearing color to OpenGL. Calls glClearColor (in RGBA mode) or glClearIndex (in color-index mode) with the color c. Applies to this widgets GL context.

See also:

qglColor(), QGLContext::currentContext(), QColor

Definition at line 3093 of file qgl.cpp.

References c, QGLContext::colorIndex(), QGLContext::currentContext(), d, QGLContext::format(), i, and QGLFormat::rgba().

Referenced by QGLOverlayWidget::initializeGL(), and QView3DWidget::initializeGL().

{
#ifdef Q_WS_QWS
    glClearColor((GLfloat)c.red() / 255.0, (GLfloat)c.green() / 255.0,
                 (GLfloat)c.blue() / 255.0, (GLfloat) c.alpha() / 255.0);
#else
    Q_D(const QGLWidget);
    const QGLContext *ctx = QGLContext::currentContext();
    if (ctx) {
        if (ctx->format().rgba())
            glClearColor((GLfloat)c.red() / 255.0, (GLfloat)c.green() / 255.0,
                          (GLfloat)c.blue() / 255.0, (GLfloat) c.alpha() / 255.0);
        else if (!d->cmap.isEmpty()) { // QGLColormap in use?
            int i = d->cmap.find(c.rgb());
            if (i < 0)
                i = d->cmap.findNearest(c.rgb());
            glClearIndex(i);
        } else
            glClearIndex(ctx->colorIndex(c));
    }
#endif
}

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bool QGLWidget::isValid

(

)

const

Returns true if the widget has a valid GL rendering context; otherwise returns false. A widget will be invalid if the system has no OpenGL support.

Definition at line 2530 of file qgl.cpp.

References d.

Referenced by glDraw(), glInit(), renderPixmap(), and resizeEvent().

{
    Q_D(const QGLWidget);
    return d->glcx && d->glcx->isValid();
}

bool QGLWidget::isSharing

(

)

const

Returns true if this widget's GL context is shared with another GL context, otherwise false is returned. The GL system may fail to provide context sharing if the two QGLWidgets use different formats.

See also:

format()

Definition at line 2547 of file qgl.cpp.

References d.

{
    Q_D(const QGLWidget);
    return d->glcx->isSharing();
}

void QGLWidget::makeCurrent

(

)

Makes this widget the current widget for OpenGL operations, i.e. makes the widget's rendering context the current OpenGL rendering context.

Definition at line 2561 of file qgl.cpp.

References d.

Referenced by QView3DWidget::addWidget(), QView3DWidget::beginAddingWidgets(), QView3DWidget::clear(), QView3DWidget::endAddingWidgets(), event(), glDraw(), glInit(), GLWidget::GLWidget(), grabFrameBuffer(), QGLExtensions::init(), GLWidget::initPbuffer(), QView3DWidget::keyReleaseEvent(), QGLDrawable::makeCurrent(), QView3DWidget::mouseMoveEvent(), renderText(), resizeEvent(), QView3DWidget::wheelEvent(), and QView3DWidget::widgetAt().

{
    Q_D(QGLWidget);
    d->glcx->makeCurrent();
}

void QGLWidget::doneCurrent

(

)

Makes no GL context the current context. Normally, you do not need to call this function; QGLContext calls it as necessary. However, it may be useful in multithreaded environments.

Definition at line 2575 of file qgl.cpp.

References d.

Referenced by event().

{
    Q_D(QGLWidget);
    d->glcx->doneCurrent();
}

bool QGLWidget::doubleBuffer

(

)

const

Returns true if the contained GL rendering context has double buffering; otherwise returns false.

See also:

QGLFormat::doubleBuffer()

Definition at line 3420 of file qgl.cpp.

References d.

Referenced by glDraw().

{
    Q_D(const QGLWidget);
    return d->glcx->format().doubleBuffer();
}

void QGLWidget::swapBuffers

(

)

Swaps the screen contents with an off-screen buffer. This only works if the widget's format specifies double buffer mode.

Normally, there is no need to explicitly call this function because it is done automatically after each widget repaint, i.e. each time after paintGL() has been executed.

See also:

doubleBuffer(), setAutoBufferSwap(), QGLFormat::setDoubleBuffer()

Definition at line 2594 of file qgl.cpp.

References d.

Referenced by glDraw(), and QGLDrawable::swapBuffers().

{
    Q_D(QGLWidget);
    d->glcx->swapBuffers();
}

QGLFormat QGLWidget::format

(

)

const

Returns the format of the contained GL rendering context.

Definition at line 3408 of file qgl.cpp.

References d.

Referenced by QGLDrawable::format(), grabFrameBuffer(), main(), QGLWidget(), and setFormat().

{
    Q_D(const QGLWidget);
    return d->glcx->format();
}

void QGLWidget::setFormat

(

const QGLFormat &

format

)

Sets a new format for this widget.

If the underlying OpenGL/Window system cannot satisfy all the features requested in format, the nearest subset of features will be used. After creation, the format() method will return the actual rendering context format obtained.

The widget will be assigned a new QGLContext, and the initializeGL() function will be executed for this new context before the first resizeGL() or paintGL().

This method will try to keep any existing display list sharing with other QGLWidgets, but it may fail. Use isSharing() to test.

See also:

format(), isSharing(), isValid()

Definition at line 2645 of file qgl.cpp.

References format(), QGLContext, and setContext().

{
    setContext(new QGLContext(format,this));
}

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const QGLContext * QGLWidget::context

(

)

const

Returns the context of this widget.

It is possible that the context is not valid (see isValid()), for example, if the underlying hardware does not support the format attributes that were requested.

Definition at line 3414 of file qgl.cpp.

References d.

Referenced by QGLWidgetPrivate::initContext(), QGLOverlayWidget::initializeGL(), QGLWidget(), and setContext().

{
    Q_D(const QGLWidget);
    return d->glcx;
}

void QGLWidget::setContext	(	QGLContext *	context,
		const QGLContext *	shareContext = 0,
		bool	deleteOldContext = true
	)

Definition at line 1110 of file qgl_x11.cpp.

References a, QWidget::backgroundRole(), Qt::black, choose_cmap(), context(), QWidget::create(), d, QGLContext::device(), QGLContext::deviceIsPixmap(), QX11Info::display(), QWidget::height(), QWidget::hide(), QColormap::instance(), QWidget::isVisible(), p, QWidget::palette(), QWidget::parentWidget(), QColormap::pixel(), qWarning(), QWidget::show(), QWidget::testAttribute(), w, Qt::WA_WState_Created, QWidget::width(), QWidget::window(), QGLContext::windowCreated(), QWidget::winId(), QWidget::x(), X11, and QWidget::y().

Referenced by setFormat().

{
    Q_D(QGLWidget);
    if (context == 0) {
        qWarning("QGLWidget::setContext: Cannot set null context");
        return;
    }
    if (!context->deviceIsPixmap() && context->device() != this) {
        qWarning("QGLWidget::setContext: Context must refer to this widget");
        return;
    }

    if (d->glcx)
        d->glcx->doneCurrent();
    QGLContext* oldcx = d->glcx;
    d->glcx = context;

    bool createFailed = false;
    if (!d->glcx->isValid()) {
        if (!d->glcx->create(shareContext ? shareContext : oldcx))
            createFailed = true;
    }
    if (createFailed) {
        if (deleteOldContext)
            delete oldcx;
        return;
    }

    if (d->glcx->windowCreated() || d->glcx->deviceIsPixmap()) {
        if (deleteOldContext)
            delete oldcx;
        return;
    }

    bool visible = isVisible();
    if (visible)
        hide();

    XVisualInfo *vi = (XVisualInfo*)d->glcx->d_func()->vi;
    XSetWindowAttributes a;

    QColormap colmap = QColormap::instance(vi->screen);
    a.colormap = choose_cmap(QX11Info::display(), vi);        // find best colormap
    a.background_pixel = colmap.pixel(palette().color(backgroundRole()));
    a.border_pixel = colmap.pixel(Qt::black);
    Window p = RootWindow(X11->display, vi->screen);
    if (parentWidget())
        p = parentWidget()->winId();

    Window w = XCreateWindow(X11->display, p, x(), y(), width(), height(),
                              0, vi->depth, InputOutput, vi->visual,
                              CWBackPixel|CWBorderPixel|CWColormap, &a);
    Window *cmw;
    Window *cmwret;
    int count;
    if (XGetWMColormapWindows(X11->display, window()->winId(),
                                &cmwret, &count)) {
        cmw = new Window[count+1];
        memcpy((char *)cmw, (char *)cmwret, sizeof(Window)*count);
        XFree((char *)cmwret);
        int i;
        for (i=0; i<count; i++) {
            if (cmw[i] == winId()) {                // replace old window
                cmw[i] = w;
                break;
            }
        }
        if (i >= count)                        // append new window
            cmw[count++] = w;
    } else {
        count = 1;
        cmw = new Window[count];
        cmw[0] = w;
    }

#if defined(GLX_MESA_release_buffers) && defined(QGL_USE_MESA_EXT)
    if (oldcx && oldcx->windowCreated())
        glXReleaseBuffersMESA(X11->display, winId());
#endif
    if (deleteOldContext)
        delete oldcx;
    oldcx = 0;

    if (testAttribute(Qt::WA_WState_Created))
        create(w);
    else
        d->createWinId(w);
    XSetWMColormapWindows(X11->display, window()->winId(), cmw, count);
    delete [] cmw;

    // calling QWidget::create() will always result in a new paint
    // engine being created - get rid of it and replace it with our
    // own

    if (visible)
        show();
    XFlush(X11->display);
    d->glcx->setWindowCreated(true);
}

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QPixmap QGLWidget::renderPixmap	(	int	w = 0,
		int	h = 0,
		bool	useContext = false
	)

Renders the current scene on a pixmap and returns the pixmap.

You can use this method on both visible and invisible QGLWidgets.

This method will create a pixmap and a temporary QGLContext to render on the pixmap. It will then call initializeGL(), resizeGL(), and paintGL() on this context. Finally, the widget's original GL context is restored.

The size of the pixmap will be w pixels wide and h pixels high unless one of these parameters is 0 (the default), in which case the pixmap will have the same size as the widget.

If useContext is true, this method will try to be more efficient by using the existing GL context to render the pixmap. The default is false. Only use true if you understand the risks. Note that under Windows a temporary context has to be created and usage of the useContext parameter is not supported.

Overlays are not rendered onto the pixmap.

If the GL rendering context and the desktop have different bit depths, the result will most likely look surprising.

Note that the creation of display lists, modifications of the view frustum etc. should be done from within initializeGL(). If this is not done, the temporary QGLContext will not be initialized properly, and the rendered pixmap may be incomplete/corrupted.

Definition at line 2886 of file qgl.cpp.

References QX11Info::appVisual(), d, QPixmap::depth(), QX11Info::depth(), QGLContext::doneCurrent(), QPixmap::fromImage(), image, isValid(), QGLContext::makeCurrent(), p, QGLContext, QWidget::QPixmap, qt_x11_preferred_pixmap_depth, QGLFormat::setDirectRendering(), QGLFormat::setDoubleBuffer(), QWidget::size(), QPixmap::toImage(), updateGL(), and QX11Info::visual().

Referenced by MainWindow::renderIntoPixmap().

{
    Q_D(QGLWidget);
    QSize sz = size();
    if ((w > 0) && (h > 0))
        sz = QSize(w, h);

#if defined(Q_WS_X11)
    extern int qt_x11_preferred_pixmap_depth;
    int old_depth = qt_x11_preferred_pixmap_depth;
    qt_x11_preferred_pixmap_depth = x11Info().depth();
    QPixmap pm(sz);
    qt_x11_preferred_pixmap_depth = old_depth;
    QX11Info xinfo = x11Info();

    // make sure we use a pixmap with the same depth/visual as the widget
    if (xinfo.visual() != QX11Info::appVisual()) {
        QX11InfoData* xd = pm.x11Info().getX11Data(true);
        xd->depth = xinfo.depth();
        xd->visual = static_cast<Visual *>(xinfo.visual());
        const_cast<QX11Info &>(pm.x11Info()).setX11Data(xd);
    }

#else
    QPixmap pm(sz);
#endif

    d->glcx->doneCurrent();

    bool success = true;

    if (useContext && isValid() && d->renderCxPm(&pm))
        return pm;

    QGLFormat fmt = d->glcx->requestedFormat();
    fmt.setDirectRendering(false);                // Direct is unlikely to work
    fmt.setDoubleBuffer(false);                // We don't need dbl buf

    QGLContext* ocx = d->glcx;
    ocx->doneCurrent();
    d->glcx = new QGLContext(fmt, &pm);
    d->glcx->create();

    if (d->glcx->isValid())
        updateGL();
    else
        success = false;

    delete d->glcx;
    d->glcx = ocx;

    ocx->makeCurrent();

    if (success) {
#if defined(Q_WS_X11)
        if (xinfo.visual() != QX11Info::appVisual()) {
            QImage image = pm.toImage();
            QPixmap p = QPixmap::fromImage(image);
            return p;
        }
#endif
        return pm;
    }
    return QPixmap();
}

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QImage QGLWidget::grabFrameBuffer

(

bool

withAlpha = false

)

Returns an image of the frame buffer. If withAlpha is true the alpha channel is included.

Depending on your hardware, you can explicitly select which color buffer to grab with a glReadBuffer() call before calling this function.

Definition at line 2962 of file qgl.cpp.

References a, alpha, QImage::bits(), QColormap::colormap(), format(), QImage::Format_ARGB32, QImage::Format_Indexed8, QImage::Format_RGB32, h, QWidget::height(), i, QColormap::instance(), makeCurrent(), QImage::mirrored(), p, QImage::rgbSwapped(), QImage::setColor(), QImage::setNumColors(), w, and QWidget::width().

Referenced by MainWindow::grabFrameBuffer().

{
    makeCurrent();
    QImage res;
    int w = width();
    int h = height();
    if (format().rgba()) {
        res = QImage(w, h, withAlpha ? QImage::Format_ARGB32 : QImage::Format_RGB32);
        glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, res.bits());
        if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
            // OpenGL gives RGBA; Qt wants ARGB
            uint *p = (uint*)res.bits();
            uint *end = p + w*h;
            if (withAlpha && format().alpha()) {
                while (p < end) {
                    uint a = *p << 24;
                    *p = (*p >> 8) | a;
                    p++;
                }
            } else {
                while (p < end) {
                    *p = 0xFF000000 | (*p>>8);
                    ++p;
                }
            }
        } else {
            // OpenGL gives ABGR (i.e. RGBA backwards); Qt wants ARGB
            res = res.rgbSwapped();
        }
    } else {
#if defined (Q_WS_WIN)
        res = QImage(w, h, QImage::Format_Indexed8);
        glReadPixels(0, 0, w, h, GL_COLOR_INDEX, GL_UNSIGNED_BYTE, res.bits());
        const QVector<QColor> pal = QColormap::instance().colormap();
        if (pal.size()) {
            res.setNumColors(pal.size());
            for (int i = 0; i < pal.size(); i++)
                res.setColor(i, pal.at(i).rgb());
        }
#endif
    }

    return res.mirrored();
}

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void QGLWidget::makeOverlayCurrent

(

)

Makes the overlay context of this widget current. Use this if you need to issue OpenGL commands to the overlay context outside of initializeOverlayGL(), resizeOverlayGL(), and paintOverlayGL().

Does nothing if this widget has no overlay.

See also:

makeCurrent()

Definition at line 1088 of file qgl_x11.cpp.

References d.

{
    Q_D(QGLWidget);
    if (d->olw)
        d->olw->makeCurrent();
}

const QGLContext * QGLWidget::overlayContext

(

)

const

Returns the overlay context of this widget, or 0 if this widget has no overlay.

See also:

context()

Definition at line 1078 of file qgl_x11.cpp.

References d.

{
    Q_D(const QGLWidget);
    if (d->olw)
        return d->olw->context();
    else
        return 0;
}

QImage QGLWidget::convertToGLFormat

(

const QImage &

img

)

[static]

Converts the image img into the unnamed format expected by OpenGL functions such as glTexImage2D(). The returned image is not usable as a QImage, but QImage::width(), QImage::height() and QImage::bits() may be used with OpenGL.

###

opengl/texture example The following few lines are from the texture example. Most of the code is irrelevant, so we just quote the relevant bits:

opengl/texture/gltexobj.cpp tex1 tex1 gllogo.bmp

We create tex1 (and another variable) for OpenGL, and load a real image into buf.

convertToGLFormat convertToGLFormat

A few lines later, we convert buf into OpenGL format and store it in tex1.

glTexImage2D glTexImage2D tex1.bits

Note the dimension restrictions for texture images as described in the glTexImage2D() documentation. The width must be 2^m + 2*border and the height 2^n + 2*border where m and n are integers and border is either 0 or 1.

Another function in the same example uses tex1 with OpenGL.

Definition at line 3157 of file qgl.cpp.

References QImage::convertToFormat(), QImage::Format_ARGB32, QImage::height(), i, QImage::mirrored(), p, QImage::rgbSwapped(), QImage::scanLine(), and QImage::width().

Referenced by QView3DWidget::addTexture().

{
    QImage res = img.convertToFormat(QImage::Format_ARGB32);
    res = res.mirrored();

    if (QSysInfo::ByteOrder == QSysInfo::BigEndian) {
        // Qt has ARGB; OpenGL wants RGBA
        for (int i=0; i < res.height(); i++) {
            uint *p = (uint*)res.scanLine(i);
            uint *end = p + res.width();
            while (p < end) {
                *p = (*p << 8) | ((*p >> 24) & 0xFF);
                p++;
            }
        }
    }
    else {
        // Qt has ARGB; OpenGL wants ABGR (i.e. RGBA backwards)
        res = res.rgbSwapped();
    }
    return res;
}

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void QGLWidget::setMouseTracking

(

bool

enable

)

If enable is true then mouse tracking is enabled; otherwise it is disabled.

Reimplemented from QWidget.

Definition at line 1055 of file qgl_x11.cpp.

References d, and QWidget::setMouseTracking().

{
    Q_D(QGLWidget);
    if (d->olw)
        d->olw->setMouseTracking(enable);
    QWidget::setMouseTracking(enable);
}

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const QGLColormap & QGLWidget::colormap

(

)

const

Returns the colormap for this widget.

Usually it is only top-level widgets that can have different colormaps installed. Asking for the colormap of a child widget will return the colormap for the child's top-level widget.

If no colormap has been set for this widget, the QColormap returned will be empty.

See also:

setColormap()

Definition at line 1212 of file qgl_x11.cpp.

References d.

{
    Q_D(const QGLWidget);
    return d->cmap;
}

void QGLWidget::setColormap

(

const QGLColormap &

cmap

)

Set the colormap for this widget to cmap. Usually it is only top-level widgets that can have colormaps installed.

See also:

colormap()

Definition at line 1280 of file qgl_x11.cpp.

References c, d, qCanAllocColors(), qStoreColors(), qWarning(), QWidget::window(), QWidget::winId(), and X11.

{
    Q_D(QGLWidget);
    QWidget * tlw = window(); // must return a valid widget

    d->cmap = c;
    if (!d->cmap.handle())
        return;

    if (!qCanAllocColors(this)) {
        qWarning("QGLWidget::setColormap: Cannot create a read/write "
                  "colormap for this visual");
        return;
    }

    // If the child GL widget is not of the same visual class as the
    // toplevel widget we will get in trouble..
    Window wid = tlw->winId();
    Visual * vis = (Visual *) tlw->x11Info().visual();;
    VisualID cvId = XVisualIDFromVisual((Visual *) x11Info().visual());
    VisualID tvId = XVisualIDFromVisual((Visual *) tlw->x11Info().visual());
    if (cvId != tvId) {
        wid = winId();
        vis = (Visual *) x11Info().visual();
    }

    if (!d->cmap.handle()) // allocate a cmap if necessary
        d->cmap.setHandle(XCreateColormap(X11->display, wid, vis, AllocAll));

    qStoreColors(this, (Colormap) d->cmap.handle(), c);
    XSetWindowColormap(X11->display, wid, (Colormap) d->cmap.handle());

    // tell the wm that this window has a special colormap
    Window * cmw;
    Window * cmwret;
    int count;
    if (XGetWMColormapWindows(X11->display, tlw->winId(), &cmwret, &count))
    {
        cmw = new Window[count+1];
        memcpy((char *) cmw, (char *) cmwret, sizeof(Window) * count);
        XFree((char *) cmwret);
        int i;
        for (i = 0; i < count; i++) {
            if (cmw[i] == winId()) {
                break;
            }
        }
        if (i >= count)   // append new window only if not in the list
            cmw[count++] = winId();
    } else {
        count = 1;
        cmw = new Window[count];
        cmw[0] = winId();
    }
    XSetWMColormapWindows(X11->display, tlw->winId(), cmw, count);
    delete [] cmw;
}

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void QGLWidget::renderText	(	int	x,
		int	y,
		const QString &	str,
		const QFont &	font = QFont(),
		int	listBase = 2000
	)

Renders the string str into the GL context of this widget.

x and y are specified in window coordinates, with the origin in the upper left-hand corner of the window. If font is not specified, the currently set application font will be used to render the string. To change the color of the rendered text you can use the glColor() call (or the qglColor() convenience function), just before the renderText() call. Note that if you have GL_LIGHTING enabled, the string will not appear in the color you want. You should therefore switch lighting off before using renderText().

listBase specifies the index of the first display list that is generated by this function. The default value is 2000. 256 display lists will be generated, one for each of the first 256 characters in the font that is used to render the string. If several fonts are used in the same widget, the display lists for these fonts will follow the last generated list. You would normally not have to change this value unless you are using lists in the same range. The lists are deleted when the widget is destroyed.

Warning:

This function only works reliably with ASCII strings.

To draw strings with unicode characters, or draw text to a QGLPixelBuffer, open a QPainter and call QPainter::drawText() instead.

Definition at line 3308 of file qgl.cpp.

References QWidget::font(), fontDisplayListBase(), QWidget::height(), makeCurrent(), NULL, QFont::overline(), qt_drawFontLining(), QFont::strikeOut(), QString::toLatin1(), QFont::underline(), and QWidget::width().

Referenced by QView3DWidget::paintGL().

{
#ifndef Q_WS_QWS
    makeCurrent();
    glPushAttrib(GL_ALL_ATTRIB_BITS);
    glDisable(GL_TEXTURE_1D);
    glDisable(GL_TEXTURE_2D);
    glDisable(GL_DEPTH_TEST);
    glDisable(GL_CULL_FACE);

    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glLoadIdentity();
    glOrtho(0, width(), height(), 0, -1, 1);
    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();

    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_BLEND);
    glAlphaFunc(GL_GREATER, 0.0);
    glEnable(GL_ALPHA_TEST);
    glRasterPos2i(0, 0);
    glBitmap(0, 0, 0, 0, x, -y, NULL);
    glListBase(fontDisplayListBase(font, listBase));
    QByteArray cstr(str.toLatin1());
    glCallLists(cstr.size(), GL_UNSIGNED_BYTE, cstr.constData());

    if (font.underline() || font.strikeOut() || font.overline())
        qt_drawFontLining(x, y, str, font);

    glPopMatrix();
    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glPopAttrib();
#endif
}

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void QGLWidget::renderText	(	double	x,
		double	y,
		double	z,
		const QString &	str,
		const QFont &	font = QFont(),
		int	listBase = 2000
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. x, y and z are specified in scene or object coordinates relative to the currently set projection and model matrices. This can be useful if you want to annotate models with text labels and have the labels move with the model as it is rotated etc.

To draw strings with unicode characters, or draw text to a QGLPixelBuffer, open a QPainter and call QPainter::drawText() instead. Note that you will have to do the screen-coordinate to object-coordinate transform yourself.

Definition at line 3358 of file qgl.cpp.

References QWidget::font(), fontDisplayListBase(), GLint, QWidget::height(), makeCurrent(), QFont::overline(), qgluProject(), qt_drawFontLining(), QFont::strikeOut(), QString::toLatin1(), QFont::underline(), and QWidget::width().

{
#ifndef Q_WS_QWS
    makeCurrent();
    glPushAttrib(GL_ALL_ATTRIB_BITS);

    glDisable(GL_TEXTURE_1D);
    glDisable(GL_TEXTURE_2D);
    glDisable(GL_CULL_FACE);

    glRasterPos3d(x, y, z);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_BLEND);
    glAlphaFunc(GL_GREATER, 0.0);
    glEnable(GL_ALPHA_TEST);
    glListBase(fontDisplayListBase(font, listBase));
    QByteArray cstr(str.toLatin1());
    glCallLists(cstr.size(), GL_UNSIGNED_BYTE, cstr.constData());

    if (font.underline() || font.strikeOut() || font.overline()) {
        GLdouble model[4][4], proj[4][4];
        GLint view[4];
        glGetDoublev(GL_MODELVIEW_MATRIX, &model[0][0]);
        glGetDoublev(GL_PROJECTION_MATRIX, &proj[0][0]);
        glGetIntegerv(GL_VIEWPORT, &view[0]);

        GLdouble win_x = 0, win_y = 0, win_z = 0;
        qgluProject(x, y, z, &model[0][0], &proj[0][0], &view[0],
                    &win_x, &win_y, &win_z);
        win_y = height() - win_y; // y is inverted

        glMatrixMode(GL_PROJECTION);
        glPushMatrix();
        glLoadIdentity();
        glOrtho(0, width(), height(), 0, -1, 1);
        glMatrixMode(GL_MODELVIEW);
        glPushMatrix();
        glLoadIdentity();

        qt_drawFontLining(win_x, win_y, str, font);

        glPopMatrix();
        glMatrixMode(GL_PROJECTION);
        glPopMatrix();
    }
    glPopAttrib();
#endif
}

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QPaintEngine * QGLWidget::paintEngine

(

)

const [virtual]

Returns a pointer to the paint engine used for drawing on the device.

Reimplemented from QWidget.

Definition at line 3494 of file qgl.cpp.

Referenced by QWidgetPrivate::drawWidget().

{
    return qt_gl_engine();
}

GLuint QGLWidget::bindTexture	(	const QImage &	image,
		GLenum	target = GL_TEXTURE_2D,
		GLint	format = GL_RGBA
	)

Calls QGLContext:bindTexture(image, target, format) on the currently set context.

See also:

deleteTexture()

Definition at line 3444 of file qgl.cpp.

References d, and image.

Referenced by QGLDrawable::bindTexture(), and GLWidget::initializeGL().

{
    Q_D(QGLWidget);
    return d->glcx->bindTexture(image, target, format);
}

GLuint QGLWidget::bindTexture	(	const QPixmap &	pixmap,
		GLenum	target = GL_TEXTURE_2D,
		GLint	format = GL_RGBA
	)

Calls QGLContext:bindTexture(pixmap, target, format) on the currently set context.

See also:

deleteTexture()

Definition at line 3456 of file qgl.cpp.

References d.

{
    Q_D(QGLWidget);
    return d->glcx->bindTexture(pixmap, target, format);
}

GLuint QGLWidget::bindTexture

(

const QString &

fileName

)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Calls QGLContext::bindTexture(fileName) on the currently set context.

See also:

deleteTexture()

Definition at line 3468 of file qgl.cpp.

References d.

{
    Q_D(QGLWidget);
    return d->glcx->bindTexture(fileName);
}

void QGLWidget::deleteTexture

(

GLuint

id

)

Calls QGLContext::deleteTexture(id) on the currently set context.

See also:

bindTexture()

Definition at line 3480 of file qgl.cpp.

References d.

{
    Q_D(QGLWidget);
    d->glcx->deleteTexture(id);
}

void QGLWidget::updateGL

(

)

[virtual, slot]

Updates the widget by calling glDraw().

Definition at line 2700 of file qgl.cpp.

References glDraw(), and QWidget::updatesEnabled().

Referenced by GLWidget::advanceGears(), QView3DWidget::keyReleaseEvent(), QView3DWidget::mouseMoveEvent(), renderPixmap(), GLWidget::rotateBy(), GLWidget::setClearColor(), GLWidget::setXRotation(), GLWidget::setYRotation(), GLWidget::setZRotation(), and QView3DWidget::wheelEvent().

{
    if (updatesEnabled())
        glDraw();
}

void QGLWidget::updateOverlayGL

(

)

[virtual, slot]

Updates the widget's overlay (if any). Will cause the virtual function paintOverlayGL() to be executed.

The widget's rendering context will become the current context and initializeGL() will be called if it hasn't already been called.

Definition at line 1096 of file qgl_x11.cpp.

References d.

Referenced by paintEvent().

{
    Q_D(QGLWidget);
    if (d->olw)
        d->olw->updateGL();
}

bool QGLWidget::event

(

QEvent *

e

)

[protected, virtual]

Reimplemented from QWidget.

Definition at line 1041 of file qgl_x11.cpp.

References doneCurrent(), QWidget::event(), QEvent::Hide, makeCurrent(), and QEvent::type().

Referenced by GLWidget::paintEvent(), and GLWidget::showEvent().

{
    // prevents X errors on some systems, where we get a flush to a
    // hidden widget
    if (e->type() == QEvent::Hide) {
        makeCurrent();
        glFinish();
        doneCurrent();
    }

    return QWidget::event(e);
}

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void QGLWidget::initializeGL

(

)

[protected, virtual]

This virtual function is called once before the first call to paintGL() or resizeGL(), and then once whenever the widget has been assigned a new QGLContext. Reimplement it in a subclass.

This function should set up any required OpenGL context rendering flags, defining display lists, etc.

There is no need to call makeCurrent() because this has already been done when this function is called.

Definition at line 2730 of file qgl.cpp.

Referenced by glInit().

{
}

void QGLWidget::resizeGL	(	int	width,
		int	height
	)			[protected, virtual]

This virtual function is called whenever the widget has been resized. The new size is passed in width and height. Reimplement it in a subclass.

There is no need to call makeCurrent() because this has already been done when this function is called.

Definition at line 2759 of file qgl.cpp.

Referenced by glDraw(), and resizeEvent().

{
}

void QGLWidget::paintGL

(

)

[protected, virtual]

This virtual function is called whenever the widget needs to be painted. Reimplement it in a subclass.

There is no need to call makeCurrent() because this has already been done when this function is called.

Definition at line 2743 of file qgl.cpp.

Referenced by glDraw().

{
}

void QGLWidget::initializeOverlayGL

(

)

[protected, virtual]

This virtual function is used in the same manner as initializeGL() except that it operates on the widget's overlay context instead of the widget's main context. This means that initializeOverlayGL() is called once before the first call to paintOverlayGL() or resizeOverlayGL(). Reimplement it in a subclass.

This function should set up any required OpenGL context rendering flags, defining display lists, etc. for the overlay context.

There is no need to call makeOverlayCurrent() because this has already been done when this function is called.

Definition at line 2779 of file qgl.cpp.

Referenced by QGLOverlayWidget::initializeGL().

{
}

void QGLWidget::resizeOverlayGL	(	int	width,
		int	height
	)			[protected, virtual]

This virtual function is used in the same manner as paintGL() except that it operates on the widget's overlay context instead of the widget's main context. This means that resizeOverlayGL() is called whenever the widget has been resized. The new size is passed in width and height. Reimplement it in a subclass.

There is no need to call makeOverlayCurrent() because this has already been done when this function is called.

Definition at line 2813 of file qgl.cpp.

Referenced by QGLOverlayWidget::resizeGL().

{
}

void QGLWidget::paintOverlayGL

(

)

[protected, virtual]

This virtual function is used in the same manner as paintGL() except that it operates on the widget's overlay context instead of the widget's main context. This means that paintOverlayGL() is called whenever the widget's overlay needs to be painted. Reimplement it in a subclass.

There is no need to call makeOverlayCurrent() because this has already been done when this function is called.

Definition at line 2795 of file qgl.cpp.

Referenced by QGLOverlayWidget::paintGL().

{
}

void QGLWidget::setAutoBufferSwap

(

bool

on

)

[protected]

If on is true automatic GL buffer swapping is switched on; otherwise it is switched off.

If on is true and the widget is using a double-buffered format, the background and foreground GL buffers will automatically be swapped after each paintGL() call.

The buffer auto-swapping is on by default.

See also:

autoBufferSwap(), doubleBuffer(), swapBuffers()

Definition at line 3426 of file qgl.cpp.

References d.

{
    Q_D(QGLWidget);
    d->autoSwap = on;
}

bool QGLWidget::autoBufferSwap

(

)

const [protected]

Returns true if the widget is doing automatic GL buffer swapping; otherwise returns false.

See also:

setAutoBufferSwap()

Definition at line 3432 of file qgl.cpp.

References d.

Referenced by QGLDrawable::swapBuffers().

{
    Q_D(const QGLWidget);
    return d->autoSwap;
}

void QGLWidget::paintEvent

(

QPaintEvent *

event

)

[protected, virtual]

Handles paint events passed in the event parameter. Will cause the virtual paintGL() function to be called.

The widget's rendering context will become the current context and initializeGL() will be called if it hasn't already been called.

Reimplemented from QWidget.

Definition at line 2830 of file qgl.cpp.

References glDraw(), updateOverlayGL(), and QWidget::updatesEnabled().

{
    if (updatesEnabled()) {
        glDraw();
        updateOverlayGL();
    }
}

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void QGLWidget::resizeEvent

(

QResizeEvent *

event

)

[protected, virtual]

Handles resize events that are passed in the event parameter. Calls the virtual function resizeGL().

Reimplemented from QWidget.

Definition at line 1064 of file qgl_x11.cpp.

References d, glInit(), QWidget::height(), isValid(), makeCurrent(), QWidget::rect(), resizeGL(), and QWidget::width().

{
    Q_D(QGLWidget);
    if (!isValid())
        return;
    makeCurrent();
    if (!d->glcx->initialized())
        glInit();
    glXWaitX();
    resizeGL(width(), height());
    if (d->olw)
        d->olw->setGeometry(rect());
}

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void QGLWidget::glInit

(

)

[protected, virtual]

Initializes OpenGL for this widget's context. Calls the virtual function initializeGL().

Definition at line 3014 of file qgl.cpp.

References d, initializeGL(), isValid(), and makeCurrent().

Referenced by glDraw(), and resizeEvent().

{
    Q_D(QGLWidget);
    if (!isValid())
        return;
    makeCurrent();
    initializeGL();
    d->glcx->setInitialized(true);
}

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void QGLWidget::glDraw

(

)

[protected, virtual]

Executes the virtual function paintGL().

The widget's rendering context will become the current context and initializeGL() will be called if it hasn't already been called.

Definition at line 3032 of file qgl.cpp.

References d, doubleBuffer(), glInit(), isValid(), makeCurrent(), paintGL(), resizeGL(), and swapBuffers().

Referenced by paintEvent(), and updateGL().

{
    Q_D(QGLWidget);
    if (!isValid())
        return;
    makeCurrent();
#ifndef Q_WS_QWS
    if (d->glcx->deviceIsPixmap())
        glDrawBuffer(GL_FRONT);
#endif
    if (!d->glcx->initialized()) {
        glInit();
        resizeGL(d->glcx->device()->width(), d->glcx->device()->height()); // New context needs this "resize"
    }
    paintGL();
    if (doubleBuffer()) {
        if (d->autoSwap)
            swapBuffers();
    } else {
        glFlush();
    }
}

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int QGLWidget::fontDisplayListBase	(	const QFont &	font,
		int	listBase = 2000
	)			[protected]

Returns the value of the first display list that is generated for the characters in the given font. listBase indicates the base value used when generating the display lists for the font. The default value is 2000.

Definition at line 3212 of file qgl.cpp.

References base, d, QWidget::font(), QFont::key(), key, QFont::NoAntialias, QString::number(), QString::sprintf(), QFont::styleStrategy(), and QMap< Key, T >::value().

Referenced by renderText().

{
    Q_D(QGLWidget);
    int base;

    if (!d->glcx) { // this can't happen unless we run out of mem
        return 0;
    }

    // always regenerate font disp. lists for pixmaps - hw accelerated
    // contexts can't handle this otherwise
    bool regenerate = d->glcx->deviceIsPixmap();
#ifndef QT_NO_FONTCONFIG
    // font color needs to be part of the font cache key when using
    // antialiased fonts since one set of glyphs needs to be generated
    // for each font color
    QString color_key;
    if (font.styleStrategy() != QFont::NoAntialias) {
        GLfloat color[4];
        glGetFloatv(GL_CURRENT_COLOR, color);
        color_key.sprintf("%f_%f_%f",color[0], color[1], color[2]);
    }
    QString key = font.key() + color_key + QString::number((int) regenerate);
#else
    QString key = font.key() + QString::number((int) regenerate);
#endif
    if (!regenerate && (d->displayListCache.find(key) != d->displayListCache.end())) {
        base = d->displayListCache[key];
    } else {
        int maxBase = listBase - 256;
        QMap<QString,int>::ConstIterator it;
        for (it = d->displayListCache.constBegin(); it != d->displayListCache.constEnd(); ++it) {
            if (maxBase < it.value()) {
                maxBase = it.value();
            }
        }
        maxBase += 256;
        d->glcx->generateFontDisplayLists(font, maxBase);
        d->displayListCache[key] = maxBase;
        base = maxBase;
    }
    return base;
}

Here is the call graph for this function:

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Friends And Related Function Documentation

friend class QGLDrawable [friend]

Definition at line 404 of file qgl.h.

friend class QGLPixelBuffer [friend]

Definition at line 405 of file qgl.h.

friend class QGLPixelBufferPrivate [friend]

Definition at line 406 of file qgl.h.

friend class QGLContext [friend]

Reimplemented from QWidget.

Definition at line 407 of file qgl.h.

Referenced by QGLWidget(), renderPixmap(), and setFormat().

friend class QGLOverlayWidget [friend]

Definition at line 408 of file qgl.h.

friend class QOpenGLPaintEngine [friend]

Definition at line 409 of file qgl.h.

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The documentation for this class was generated from the following files:

• src/opengl/qgl.h
• src/opengl/qgl.cpp
• src/opengl/qgl_x11.cpp

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