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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QGLWidget Class Reference<br><small>[<a href="opengl.html">OpenGL module</a>]</small></h1>
<p>The QGLWidget class is a widget for rendering OpenGL graphics.
<a href="#details">More...</a>
<p><tt>#include <<a href="qgl-h.html">qgl.h</a>></tt>
<p>Inherits <a href="qwidget.html">QWidget</a> and <a href="qgl.html">QGL</a>.
<p><a href="qglwidget-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li><div class=fn><a href="#QGLWidget"><b>QGLWidget</b></a> ( QWidget * parent = 0, const char * name = 0, const QGLWidget * shareWidget = 0, WFlags f = 0 )</div></li>
<li><div class=fn><a href="#QGLWidget-2"><b>QGLWidget</b></a> ( const QGLFormat & format, QWidget * parent = 0, const char * name = 0, const QGLWidget * shareWidget = 0, WFlags f = 0 )</div></li>
<li><div class=fn><a href="#~QGLWidget"><b>~QGLWidget</b></a> ()</div></li>
<li><div class=fn>void <a href="#qglColor"><b>qglColor</b></a> ( const QColor & c ) const</div></li>
<li><div class=fn>void <a href="#qglClearColor"><b>qglClearColor</b></a> ( const QColor & c ) const</div></li>
<li><div class=fn>bool <a href="#isValid"><b>isValid</b></a> () const</div></li>
<li><div class=fn>bool <a href="#isSharing"><b>isSharing</b></a> () const</div></li>
<li><div class=fn>virtual void <a href="#makeCurrent"><b>makeCurrent</b></a> ()</div></li>
<li><div class=fn>bool <a href="#doubleBuffer"><b>doubleBuffer</b></a> () const</div></li>
<li><div class=fn>virtual void <a href="#swapBuffers"><b>swapBuffers</b></a> ()</div></li>
<li><div class=fn>QGLFormat <a href="#format"><b>format</b></a> () const</div></li>
<li><div class=fn>const QGLContext * <a href="#context"><b>context</b></a> () const</div></li>
<li><div class=fn>virtual QPixmap <a href="#renderPixmap"><b>renderPixmap</b></a> ( int w = 0, int h = 0, bool useContext = FALSE )</div></li>
<li><div class=fn>virtual QImage <a href="#grabFrameBuffer"><b>grabFrameBuffer</b></a> ( bool withAlpha = FALSE )</div></li>
<li><div class=fn>virtual void <a href="#makeOverlayCurrent"><b>makeOverlayCurrent</b></a> ()</div></li>
<li><div class=fn>const QGLContext * <a href="#overlayContext"><b>overlayContext</b></a> () const</div></li>
<li><div class=fn>const QGLColormap & <a href="#colormap"><b>colormap</b></a> () const</div></li>
<li><div class=fn>void <a href="#setColormap"><b>setColormap</b></a> ( const QGLColormap & cmap )</div></li>
</ul>
<h2>Public Slots</h2>
<ul>
<li><div class=fn>virtual void <a href="#updateGL"><b>updateGL</b></a> ()</div></li>
<li><div class=fn>virtual void <a href="#updateOverlayGL"><b>updateOverlayGL</b></a> ()</div></li>
</ul>
<h2>Static Public Members</h2>
<ul>
<li><div class=fn>QImage <a href="#convertToGLFormat"><b>convertToGLFormat</b></a> ( const QImage & img )</div></li>
</ul>
<h2>Protected Members</h2>
<ul>
<li><div class=fn>virtual void <a href="#initializeGL"><b>initializeGL</b></a> ()</div></li>
<li><div class=fn>virtual void <a href="#resizeGL"><b>resizeGL</b></a> ( int width, int height )</div></li>
<li><div class=fn>virtual void <a href="#paintGL"><b>paintGL</b></a> ()</div></li>
<li><div class=fn>virtual void <a href="#initializeOverlayGL"><b>initializeOverlayGL</b></a> ()</div></li>
<li><div class=fn>virtual void <a href="#resizeOverlayGL"><b>resizeOverlayGL</b></a> ( int width, int height )</div></li>
<li><div class=fn>virtual void <a href="#paintOverlayGL"><b>paintOverlayGL</b></a> ()</div></li>
<li><div class=fn>void <a href="#setAutoBufferSwap"><b>setAutoBufferSwap</b></a> ( bool on )</div></li>
<li><div class=fn>bool <a href="#autoBufferSwap"><b>autoBufferSwap</b></a> () const</div></li>
<li><div class=fn>virtual void <a href="#paintEvent"><b>paintEvent</b></a> ( QPaintEvent * )</div></li>
<li><div class=fn>virtual void <a href="#resizeEvent"><b>resizeEvent</b></a> ( QResizeEvent * )</div></li>
<li><div class=fn>virtual void <a href="#glInit"><b>glInit</b></a> ()</div></li>
<li><div class=fn>virtual void <a href="#glDraw"><b>glDraw</b></a> ()</div></li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
The QGLWidget class is a widget for rendering OpenGL graphics.
<p>
<p> QGLWidget provides functionality for displaying OpenGL<sup>*</sup> graphics
integrated into a Qt application. It is very simple to use. You
inherit from it and use the subclass like any other <a href="qwidget.html">QWidget</a>, except
that instead of drawing the widget's contents using <a href="qpainter.html">QPainter</a> etc.
you use the standard OpenGL rendering commands.
<p> QGLWidget provides three convenient virtual functions that you can
reimplement in your subclass to perform the typical OpenGL tasks:
<p> <ul>
<li> <a href="#paintGL">paintGL</a>() - Renders the OpenGL scene. Gets called whenever the widget
needs to be updated.
<li> <a href="#resizeGL">resizeGL</a>() - Sets up the OpenGL viewport, projection, etc. Gets
called whenever the the widget has been resized (and also when it
shown for the first time because all newly created widgets get a
resize event automatically).
<li> <a href="#initializeGL">initializeGL</a>() - Sets up the OpenGL rendering context, defines display
lists, etc. Gets called once before the first time resizeGL() or
paintGL() is called.
</ul>
<p> Here is a rough outline of how your QGLWidget subclass may look:
<p> <pre>
class MyGLDrawer : public QGLWidget
{
Q_OBJECT // must include this if you use Qt signals/slots
public:
MyGLDrawer( <a href="qwidget.html">QWidget</a> *parent, const char *name )
: QGLWidget(parent,name) {}
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();
...
}
};
</pre>
<p> If you need to trigger a repaint from places other than <a href="#paintGL">paintGL</a>() (a
typical example is when using <a href="qtimer.html">timers</a> to animate
scenes), you should call the widget's <a href="#updateGL">updateGL</a>() function.
<p> Your widget's OpenGL rendering context is made current when paintGL(),
<a href="#resizeGL">resizeGL</a>(), or <a href="#initializeGL">initializeGL</a>() 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
<a href="#makeCurrent">makeCurrent</a>() first.
<p> QGLWidget provides advanced functions for requesting a new display
<a href="qglformat.html">format</a> and you can even set a new rendering
<a href="qglcontext.html">context</a>.
<p> You can achieve sharing of OpenGL display lists between QGLWidgets
(see the documentation of the QGLWidget constructors for details).
<p> <h3> Overlays
</h3>
<a name="1"></a><p> The QGLWidget creates a GL overlay context
in addition to the normal context if overlays are supported by the
underlying system.
<p> If you want to use overlays, you specify it in the <a href="qglformat.html">format</a>. (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:
<p> <ul>
<li> <a href="#paintOverlayGL">paintOverlayGL</a>()
<li> <a href="#resizeOverlayGL">resizeOverlayGL</a>()
<li> <a href="#initializeOverlayGL">initializeOverlayGL</a>()
</ul>
<p> These methods work in the same way as the normal <a href="#paintGL">paintGL</a>() 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 <a href="#makeOverlayCurrent">makeOverlayCurrent</a>(), and you can access the
overlay context directly (e.g. to ask for its transparent color) by
calling <a href="#overlayContext">overlayContext</a>().
<p> On X servers in which the default visual is in an overlay plane,
non-GL Qt windows can also be used for overlays. See the
examples/opengl/overlay_x11 example program for details.
<p> <sup>*</sup> OpenGL is a trademark of Silicon Graphics, Inc. in the
United States and other countries.
<p>See also <a href="graphics.html">Graphics Classes</a> and <a href="images.html">Image Processing Classes</a>.
<hr><h2>Member Function Documentation</h2>
<h3 class=fn><a name="QGLWidget"></a>QGLWidget::QGLWidget ( <a href="qwidget.html">QWidget</a> * parent = 0, const char * name = 0, const <a href="qglwidget.html">QGLWidget</a> * shareWidget = 0, WFlags f = 0 )
</h3>
Constructs an OpenGL widget with a <em>parent</em> widget and a <em>name</em>.
<p> The <a href="qglformat.html#defaultFormat">default format</a> is
used. The widget will be <a href="#isValid">invalid</a> if the
system has no <a href="qglformat.html#hasOpenGL">OpenGL support</a>.
<p> The <em>parent</em>, <em>name</em> and widget flag, <em>f</em>, arguments are passed to
the <a href="qwidget.html">QWidget</a> constructor.
<p> If the <em>shareWidget</em> parameter points to a valid QGLWidget, this
widget will share OpenGL display lists with <em>shareWidget</em>. If
this widget and <em>shareWidget</em> have different <a href="#format">formats</a>, display list sharing may fail. You can check
whether display list sharing succeeded by calling <a href="#isSharing">isSharing</a>().
<p> The initialization of OpenGL rendering state, etc. should be done by
overriding the <a href="#initializeGL">initializeGL</a>() function, rather than in the constructor
of your QGLWidget subclass.
<p> <p>See also <a href="qglformat.html#defaultFormat">QGLFormat::defaultFormat</a>().
<h3 class=fn><a name="QGLWidget-2"></a>QGLWidget::QGLWidget ( const <a href="qglformat.html">QGLFormat</a> & format, <a href="qwidget.html">QWidget</a> * parent = 0, const char * name = 0, const <a href="qglwidget.html">QGLWidget</a> * shareWidget = 0, WFlags f = 0 )
</h3>
Constructs an OpenGL widget with parent <em>parent</em>, called <em>name</em>.
<p> The <em>format</em> argument specifies the desired <a href="qglformat.html">rendering options</a>. If the underlying OpenGL/Window system
cannot satisfy all the features requested in <em>format</em>, the nearest
subset of features will be used. After creation, the <a href="#format">format</a>() method
will return the actual format obtained.
<p> The widget will be <a href="#isValid">invalid</a> if the
system has no <a href="qglformat.html#hasOpenGL">OpenGL support</a>.
<p> The <em>parent</em>, <em>name</em> and widget flag, <em>f</em>, arguments are passed to
the <a href="qwidget.html">QWidget</a> constructor.
<p> If the <em>shareWidget</em> parameter points to a valid QGLWidget, this
widget will share OpenGL display lists with <em>shareWidget</em>. If
this widget and <em>shareWidget</em> have different <a href="#format">formats</a>, display list sharing may fail. You can check
whether display list sharing succeeded by calling <a href="#isSharing">isSharing</a>().
<p> The initialization of OpenGL rendering state, etc. should be done by
overriding the <a href="#initializeGL">initializeGL</a>() function, rather than in the constructor
of your QGLWidget subclass.
<p> <p>See also <a href="qglformat.html#defaultFormat">QGLFormat::defaultFormat</a>() and <a href="#isValid">isValid</a>().
<h3 class=fn><a name="~QGLWidget"></a>QGLWidget::~QGLWidget ()
</h3>
Destroys the widget.
<h3 class=fn>bool <a name="autoBufferSwap"></a>QGLWidget::autoBufferSwap () const<tt> [protected]</tt>
</h3>
<p> Returns TRUE if the widget is doing automatic GL buffer swapping;
otherwise returns FALSE.
<p> <p>See also <a href="#setAutoBufferSwap">setAutoBufferSwap</a>().
<h3 class=fn>const <a href="qglcolormap.html">QGLColormap</a> & <a name="colormap"></a>QGLWidget::colormap () const
</h3>
<p> Returns the colormap for this widget.
<p> 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.
<p> If no colormap has been set for this widget, the QColormap returned
will be empty.
<p> <p>See also <a href="#setColormap">setColormap</a>().
<h3 class=fn>const <a href="qglcontext.html">QGLContext</a> * <a name="context"></a>QGLWidget::context () const
</h3>
Returns the context of this widget.
<p> It is possible that the context is not valid (see <a href="#isValid">isValid</a>()), for
example, if the underlying hardware does not support the format
attributes that were requested.
<h3 class=fn><a href="qimage.html">QImage</a> <a name="convertToGLFormat"></a>QGLWidget::convertToGLFormat ( const <a href="qimage.html">QImage</a> & img )<tt> [static]</tt>
</h3> Converts the image <em>img</em> into the unnamed format expected by OpenGL
functions such as glTexImage2D(). The returned image is not usable
as a <a href="qimage.html">QImage</a>, but <a href="qimage.html#width">QImage::width</a>(), <a href="qimage.html#height">QImage::height</a>() and
<a href="qimage.html#bits">QImage::bits</a>() may be used with OpenGL. The following few lines are
from the texture example. Most of the code is irrelevant, so we just
quote the few lines we want:
<p>
<pre> <a href="qimage.html">QImage</a> tex1, tex2, buf;
if ( !buf.load( "gllogo.bmp" ) ) { // Load first image from file
</pre>
<p> We create <em>tex1</em> (and another variable) for OpenGL, and load a real
image into <em>buf</em>.
<p> <pre> <a name="x21"></a> tex1 = QGLWidget::<a href="#convertToGLFormat">convertToGLFormat</a>( buf ); // flipped 32bit RGBA
</pre>
<p> A few lines later, we convert <em>buf</em> into OpenGL format and store it
in <em>tex1</em>.
<p> <pre> <a name="x24"></a><a name="x23"></a> glTexImage2D( GL_TEXTURE_2D, 0, 3, tex1.<a href="qimage.html#width">width</a>(), tex1.<a href="qimage.html#height">height</a>(), 0,
<a name="x22"></a> GL_RGBA, GL_UNSIGNED_BYTE, tex1.<a href="qimage.html#bits">bits</a>() );
</pre>
<p> Another function in the same example uses <em>tex1</em> with OpenGL.
<p>Example: <a href="qglwidget.html#x21">opengl/texture/gltexobj.cpp</a>.
<h3 class=fn>bool <a name="doubleBuffer"></a>QGLWidget::doubleBuffer () const
</h3>
Returns TRUE if the contained GL rendering context has double
buffering; otherwise returns FALSE.
<p>See also <a href="qglformat.html#doubleBuffer">QGLFormat::doubleBuffer</a>().
<h3 class=fn><a href="qglformat.html">QGLFormat</a> <a name="format"></a>QGLWidget::format () const
</h3>
Returns the format of the contained GL rendering context.
<h3 class=fn>void <a name="glDraw"></a>QGLWidget::glDraw ()<tt> [virtual protected]</tt>
</h3>
Executes the virtual function <a href="#paintGL">paintGL</a>().
<p> The widget's rendering context will become the current context and
<a href="#initializeGL">initializeGL</a>() will be called if it hasn't already been called.
<h3 class=fn>void <a name="glInit"></a>QGLWidget::glInit ()<tt> [virtual protected]</tt>
</h3>
Initializes OpenGL for this widget's context. Calls the virtual
function <a href="#initializeGL">initializeGL</a>().
<h3 class=fn><a href="qimage.html">QImage</a> <a name="grabFrameBuffer"></a>QGLWidget::grabFrameBuffer ( bool withAlpha = FALSE )<tt> [virtual]</tt>
</h3>
Returns an image of the frame buffer. If <em>withAlpha</em> is TRUE the
alpha channel is included.
<h3 class=fn>void <a name="initializeGL"></a>QGLWidget::initializeGL ()<tt> [virtual protected]</tt>
</h3>
This virtual function is called once before the first call to
<a href="#paintGL">paintGL</a>() or <a href="#resizeGL">resizeGL</a>(), and then once whenever the widget has
been assigned a new <a href="qglcontext.html">QGLContext</a>. Reimplement it in a subclass.
<p> This function should set up any required OpenGL context rendering
flags, defining display lists, etc.
<p> There is no need to call <a href="#makeCurrent">makeCurrent</a>() because this has already been
done when this function is called.
<h3 class=fn>void <a name="initializeOverlayGL"></a>QGLWidget::initializeOverlayGL ()<tt> [virtual protected]</tt>
</h3>
This virtual function is used in the same manner as <a href="#initializeGL">initializeGL</a>()
except that it operates on the widget's overlay context instead of the
widget's main context. This means that <a href="#initializeOverlayGL">initializeOverlayGL</a>() is called
once before the first call to <a href="#paintOverlayGL">paintOverlayGL</a>() or <a href="#resizeOverlayGL">resizeOverlayGL</a>().
Reimplement it in a subclass.
<p> This function should set up any required OpenGL context rendering
flags, defining display lists, etc. for the overlay context.
<p> There is no need to call <a href="#makeOverlayCurrent">makeOverlayCurrent</a>() because this has already
been done when this function is called.
<h3 class=fn>bool <a name="isSharing"></a>QGLWidget::isSharing () const
</h3>
<p> Returns TRUE if display list sharing with another QGLWidget was
requested in the constructor, and the GL system was able to provide
it; otherwise returns FALSE. The GL system may fail to provide display
list sharing if the two QGLWidgets use different formats.
<p> <p>See also <a href="#format">format</a>().
<h3 class=fn>bool <a name="isValid"></a>QGLWidget::isValid () const
</h3>
<p> Returns TRUE if the widget has a valid GL rendering context; otherwise
returns FALSE. A widget will be invalid if the system has no <a href="qglformat.html#hasOpenGL">OpenGL support</a>.
<p>
<h3 class=fn>void <a name="makeCurrent"></a>QGLWidget::makeCurrent ()<tt> [virtual]</tt>
</h3>
<p> Makes this widget the current widget for OpenGL
operations, i.e. makes the widget's rendering context the current
OpenGL rendering context.
<h3 class=fn>void <a name="makeOverlayCurrent"></a>QGLWidget::makeOverlayCurrent ()<tt> [virtual]</tt>
</h3>
Makes the overlay context of this widget current. Use this if you
need to issue OpenGL commands to the overlay context outside of
<a href="#initializeOverlayGL">initializeOverlayGL</a>(), <a href="#resizeOverlayGL">resizeOverlayGL</a>(), and <a href="#paintOverlayGL">paintOverlayGL</a>().
<p> Does nothing if this widget has no overlay.
<p> <p>See also <a href="#makeCurrent">makeCurrent</a>().
<h3 class=fn>const <a href="qglcontext.html">QGLContext</a> * <a name="overlayContext"></a>QGLWidget::overlayContext () const
</h3>
Returns the overlay context of this widget, or 0 if this widget has
no overlay.
<p> <p>See also <a href="#context">context</a>().
<h3 class=fn>void <a name="paintEvent"></a>QGLWidget::paintEvent ( <a href="qpaintevent.html">QPaintEvent</a> * )<tt> [virtual protected]</tt>
</h3>
Handles paint events. Will cause the virtual <a href="#paintGL">paintGL</a>() function to
be called.
<p> The widget's rendering context will become the current context and
<a href="#initializeGL">initializeGL</a>() will be called if it hasn't already been called.
<p>Reimplemented from <a href="qwidget.html#paintEvent">QWidget</a>.
<h3 class=fn>void <a name="paintGL"></a>QGLWidget::paintGL ()<tt> [virtual protected]</tt>
</h3>
This virtual function is called whenever the widget needs to be painted.
Reimplement it in a subclass.
<p> There is no need to call <a href="#makeCurrent">makeCurrent</a>() because this has already been
done when this function is called.
<h3 class=fn>void <a name="paintOverlayGL"></a>QGLWidget::paintOverlayGL ()<tt> [virtual protected]</tt>
</h3>
This virtual function is used in the same manner as <a href="#paintGL">paintGL</a>() except
that it operates on the widget's overlay context instead of the
widget's main context. This means that <a href="#paintOverlayGL">paintOverlayGL</a>() is called
whenever the widget's overlay needs to be painted.
Reimplement it in a subclass.
<p> There is no need to call <a href="#makeOverlayCurrent">makeOverlayCurrent</a>() because this
has already been done when this function is called.
<h3 class=fn>void <a name="qglClearColor"></a>QGLWidget::qglClearColor ( const <a href="qcolor.html">QColor</a> & c ) const
</h3>
Convenience function for specifying the clearing color to
OpenGL. Calls glClearColor (in RGBA mode) or glClearIndex (in
color-index mode) with the color <em>c</em>. Applies to the current GL
context.
<p> <p>See also <a href="#qglColor">qglColor</a>(), <a href="qglcontext.html#currentContext">QGLContext::currentContext</a>() and <a href="qcolor.html">QColor</a>.
<h3 class=fn>void <a name="qglColor"></a>QGLWidget::qglColor ( const <a href="qcolor.html">QColor</a> & c ) const
</h3>
Convenience function for specifying a drawing color to OpenGL. Calls
glColor3 (in RGBA mode) or glIndex (in color-index mode) with the
color <em>c</em>. Applies to the current GL context.
<p> <p>See also <a href="#qglClearColor">qglClearColor</a>(), <a href="qglcontext.html#currentContext">QGLContext::currentContext</a>() and <a href="qcolor.html">QColor</a>.
<h3 class=fn><a href="qpixmap.html">QPixmap</a> <a name="renderPixmap"></a>QGLWidget::renderPixmap ( int w = 0, int h = 0, bool useContext = FALSE )<tt> [virtual]</tt>
</h3>
Renders the current scene on a pixmap and returns the pixmap.
<p> You may use this method on both visible and invisible QGLWidgets.
<p> This method will create a pixmap and a temporary <a href="qglcontext.html">QGLContext</a> to render
on the pixmap. It will then call <a href="#initializeGL">initializeGL</a>(), <a href="#resizeGL">resizeGL</a>(), and
<a href="#paintGL">paintGL</a>() on this context. Finally, the widget's original GL context
is restored.
<p> The size of the pixmap will be <em>w</em> pixels wide and <em>h</em> pixels high
unless one of these parameters is 0 (the default), in which case the
pixmap will have the same size as the widget.
<p> If <em>useContext</em> 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.
<p> Overlays are not rendered onto the pixmap.
<p> If the GL rendering context and the desktop have different
bit depths, the result will most likely look surprising.
<p> 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.
<h3 class=fn>void <a name="resizeEvent"></a>QGLWidget::resizeEvent ( <a href="qresizeevent.html">QResizeEvent</a> * )<tt> [virtual protected]</tt>
</h3>
Handles resize events. Calls the virtual function <a href="#resizeGL">resizeGL</a>().
<p>Reimplemented from <a href="qwidget.html#resizeEvent">QWidget</a>.
<h3 class=fn>void <a name="resizeGL"></a>QGLWidget::resizeGL ( int width, int height )<tt> [virtual protected]</tt>
</h3>
This virtual function is called whenever the widget has been resized.
The new size is passed in <em>width</em> and <em>height</em>.
Reimplement it in a subclass.
<p> There is no need to call <a href="#makeCurrent">makeCurrent</a>() because this has already been
done when this function is called.
<h3 class=fn>void <a name="resizeOverlayGL"></a>QGLWidget::resizeOverlayGL ( int width, int height )<tt> [virtual protected]</tt>
</h3>
This virtual function is used in the same manner as <a href="#paintGL">paintGL</a>() except
that it operates on the widget's overlay context instead of the
widget's main context. This means that <a href="#resizeOverlayGL">resizeOverlayGL</a>() is called
whenever the widget has been resized.
The new size is passed in <em>width</em> and <em>height</em>.
Reimplement it in a subclass.
<p> There is no need to call <a href="#makeOverlayCurrent">makeOverlayCurrent</a>() because
this has already been done when this function is called.
<h3 class=fn>void <a name="setAutoBufferSwap"></a>QGLWidget::setAutoBufferSwap ( bool on )<tt> [protected]</tt>
</h3>
<p> If <em>on</em> is TRUE automatic GL buffer swapping is switched on;
otherwise it is switched off.
<p> If <em>on</em> is TRUE and the widget is using a double-buffered format, the
background and foreground GL buffers will automatically be swapped
after each time the <a href="#paintGL">paintGL</a>() function has been called.
<p> The buffer auto-swapping is on by default.
<p> <p>See also <a href="#autoBufferSwap">autoBufferSwap</a>(), <a href="#doubleBuffer">doubleBuffer</a>() and <a href="#swapBuffers">swapBuffers</a>().
<h3 class=fn>void <a name="setColormap"></a>QGLWidget::setColormap ( const <a href="qglcolormap.html">QGLColormap</a> & cmap )
</h3>
<p> Set the colormap for this widget to <em>cmap</em>.
Usually it is only top-level widgets that can have colormaps installed.
<p> <p>See also <a href="#colormap">colormap</a>().
<h3 class=fn>void <a name="swapBuffers"></a>QGLWidget::swapBuffers ()<tt> [virtual]</tt>
</h3>
Swaps the screen contents with an off-screen buffer. This only works
if the widget's format specifies double buffer mode.
<p> Normally, there is no need to explicitly call this function because
it is done automatically after each widget repaint, i.e. each
time after <a href="#paintGL">paintGL</a>() has been executed.
<p> <p>See also <a href="#doubleBuffer">doubleBuffer</a>(), <a href="#setAutoBufferSwap">setAutoBufferSwap</a>() and <a href="qglformat.html#setDoubleBuffer">QGLFormat::setDoubleBuffer</a>().
<h3 class=fn>void <a name="updateGL"></a>QGLWidget::updateGL ()<tt> [virtual slot]</tt>
</h3>
Updates the widget by calling <a href="#glDraw">glDraw</a>().
<h3 class=fn>void <a name="updateOverlayGL"></a>QGLWidget::updateOverlayGL ()<tt> [virtual slot]</tt>
</h3>
Updates the widget's overlay (if any). Will cause the virtual
function <a href="#paintOverlayGL">paintOverlayGL</a>() to be executed.
<p> The widget's rendering context will become the current context and
<a href="#initializeGL">initializeGL</a>() will be called if it hasn't already been called.
<!-- eof -->
<hr><p>
This file is part of the <a href="index.html">Qt toolkit</a>.
Copyright © 1995-2001
<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
<table width=100% cellspacing=0 border=0><tr>
<td>Copyright © 2001
<a href="http://www.trolltech.com">Trolltech</a><td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a>
<td align=right><div align=right>Qt version 3.0.2</div>
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