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color="#004faf">Main Classes</font></a> + | <a href="annotated.html"> +<font color="#004faf">Annotated</font></a> + | <a href="groups.html"> +<font color="#004faf">Grouped Classes</font></a> + | <a href="functions.html"> +<font color="#004faf">Functions</font></a> +</td> +<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 class=fn><a href="#QGLWidget"><b>QGLWidget</b></a> ( QWidget * parent = 0, const char * name = 0, const QGLWidget * shareWidget = 0, WFlags f = 0 )</li> +<li class=fn><a href="#QGLWidget-2"><b>QGLWidget</b></a> ( QGLContext * context, QWidget * parent, const char * name = 0, const QGLWidget * shareWidget = 0, WFlags f = 0 )</li> +<li class=fn><a href="#QGLWidget-3"><b>QGLWidget</b></a> ( const QGLFormat & format, QWidget * parent = 0, const char * name = 0, const QGLWidget * shareWidget = 0, WFlags f = 0 )</li> +<li class=fn><a href="#~QGLWidget"><b>~QGLWidget</b></a> ()</li> +<li class=fn>void <a href="#qglColor"><b>qglColor</b></a> ( const QColor & c ) const</li> +<li class=fn>void <a href="#qglClearColor"><b>qglClearColor</b></a> ( const QColor & c ) const</li> +<li class=fn>bool <a href="#isValid"><b>isValid</b></a> () const</li> +<li class=fn>bool <a href="#isSharing"><b>isSharing</b></a> () const</li> +<li class=fn>virtual void <a href="#makeCurrent"><b>makeCurrent</b></a> ()</li> +<li class=fn>void <a href="#doneCurrent"><b>doneCurrent</b></a> ()</li> +<li class=fn>bool <a href="#doubleBuffer"><b>doubleBuffer</b></a> () const</li> +<li class=fn>virtual void <a href="#swapBuffers"><b>swapBuffers</b></a> ()</li> +<li class=fn>QGLFormat <a href="#format"><b>format</b></a> () const</li> +<li class=fn>const QGLContext * <a href="#context"><b>context</b></a> () const</li> +<li class=fn>virtual QPixmap <a href="#renderPixmap"><b>renderPixmap</b></a> ( int w = 0, int h = 0, bool useContext = FALSE )</li> +<li class=fn>virtual QImage <a href="#grabFrameBuffer"><b>grabFrameBuffer</b></a> ( bool withAlpha = FALSE )</li> +<li class=fn>virtual void <a href="#makeOverlayCurrent"><b>makeOverlayCurrent</b></a> ()</li> +<li class=fn>const QGLContext * <a href="#overlayContext"><b>overlayContext</b></a> () const</li> +<li class=fn>const QGLColormap & <a href="#colormap"><b>colormap</b></a> () const</li> +<li class=fn>void <a href="#setColormap"><b>setColormap</b></a> ( const QGLColormap & cmap )</li> +<li class=fn>void <a href="#renderText"><b>renderText</b></a> ( int x, int y, const QString & str, const QFont & fnt = QFont ( ), int listBase = 2000 )</li> +<li class=fn>void <a href="#renderText-2"><b>renderText</b></a> ( double x, double y, double z, const QString & str, const QFont & fnt = QFont ( ), int listBase = 2000 )</li> +</ul> +<h2>Public Slots</h2> +<ul> +<li class=fn>virtual void <a href="#updateGL"><b>updateGL</b></a> ()</li> +<li class=fn>virtual void <a href="#updateOverlayGL"><b>updateOverlayGL</b></a> ()</li> +</ul> +<h2>Static Public Members</h2> +<ul> +<li class=fn>QImage <a href="#convertToGLFormat"><b>convertToGLFormat</b></a> ( const QImage & img )</li> +</ul> +<h2>Protected Members</h2> +<ul> +<li class=fn>virtual void <a href="#initializeGL"><b>initializeGL</b></a> ()</li> +<li class=fn>virtual void <a href="#resizeGL"><b>resizeGL</b></a> ( int width, int height )</li> +<li class=fn>virtual void <a href="#paintGL"><b>paintGL</b></a> ()</li> +<li class=fn>virtual void <a href="#initializeOverlayGL"><b>initializeOverlayGL</b></a> ()</li> +<li class=fn>virtual void <a href="#resizeOverlayGL"><b>resizeOverlayGL</b></a> ( int width, int height )</li> +<li class=fn>virtual void <a href="#paintOverlayGL"><b>paintOverlayGL</b></a> ()</li> +<li class=fn>void <a href="#setAutoBufferSwap"><b>setAutoBufferSwap</b></a> ( bool on )</li> +<li class=fn>bool <a href="#autoBufferSwap"><b>autoBufferSwap</b></a> () const</li> +<li class=fn>virtual void <a href="#paintEvent"><b>paintEvent</b></a> ( QPaintEvent * )</li> +<li class=fn>virtual void <a href="#resizeEvent"><b>resizeEvent</b></a> ( QResizeEvent * )</li> +<li class=fn>virtual void <a href="#glInit"><b>glInit</b></a> ()</li> +<li class=fn>virtual void <a href="#glDraw"><b>glDraw</b></a> ()</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 +is 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 a QGLWidget subclass might 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 functions for requesting a new display <a href="qglformat.html">format</a> and you can also create widgets with +customized rendering <a href="qglcontext.html">contexts</a>. +<p> You can also share 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 <a href="qt.html#WidgetFlags">widget flag</a>, <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 ( <a href="qglcontext.html">QGLContext</a> * context, <a href="qwidget.html">QWidget</a> * parent, 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>context</em> argument is a pointer to the <a href="qglcontext.html">QGLContext</a> that +you wish to be bound to this widget. This allows you to pass in +your own QGLContext sub-classes. +<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 <a href="qt.html#WidgetFlags">widget flag</a>, <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-3"></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 <a href="qt.html#WidgetFlags">widget flag</a>, <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> + +<p> 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 relevant bits: +<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="x2118"></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="x2121"></a><a name="x2120"></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="x2119"></a> GL_RGBA, GL_UNSIGNED_BYTE, tex1.<a href="qimage.html#bits">bits</a>() ); +</pre> +<p> 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. +<p> Another function in the same example uses <em>tex1</em> with OpenGL. + +<p>Example: <a href="qglwidget.html#x2118">opengl/texture/gltexobj.cpp</a>. +<h3 class=fn>void <a name="doneCurrent"></a>QGLWidget::doneCurrent () +</h3> + +<p> Makes no GL context the current context. Normally, you do not need +to call this function; <a href="qglcontext.html">QGLContext</a> calls it as necessary. However, +it may be useful in multithreaded environments. + +<h3 class=fn>bool <a name="doubleBuffer"></a>QGLWidget::doubleBuffer () const +</h3> + +<p> Returns TRUE if the contained GL rendering context has double +buffering; otherwise returns FALSE. +<p> <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> + +<p> 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. +<p> Depending on your hardware, you can explicitly select which color +buffer to grab with a glReadBuffer() call before calling this +function. + +<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>. + +<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> + +<p> 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> + +<p> 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 can 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="renderText"></a>QGLWidget::renderText ( int x, int y, const <a href="qstring.html">QString</a> & str, const <a href="qfont.html">QFont</a> & fnt = QFont ( ), int listBase = 2000 ) +</h3> +Renders the string <em>str</em> into the GL context of this widget. +<p> <em>x</em> and <em>y</em> are specified in window coordinates, with the origin +in the upper left-hand corner of the window. If <em>fnt</em> 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 <a href="#qglColor">qglColor</a>() convenience function), +just before the <a href="#renderText">renderText</a>() 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(). +<p> <em>listBase</em> 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. +<p> Note: This function only works reliably with ASCII strings. + +<h3 class=fn>void <a name="renderText-2"></a>QGLWidget::renderText ( double x, double y, double z, const <a href="qstring.html">QString</a> & str, const <a href="qfont.html">QFont</a> & fnt = QFont ( ), int listBase = 2000 ) +</h3> This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> <em>x</em>, <em>y</em> and <em>z</em> 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. + +<h3 class=fn>void <a name="resizeEvent"></a>QGLWidget::resizeEvent ( <a href="qresizeevent.html">QResizeEvent</a> * )<tt> [virtual protected]</tt> +</h3> + +<p> 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> + +<p> 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> + +<p> 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 <a href="#paintGL">paintGL</a>() call. +<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> + +<p> 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> + +<p> 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> + +<p> 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 © 1995-2007 +<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 © 2007 +<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> +<td align=right><div align=right>Qt 3.3.8</div> +</table></div></address></body> +</html> |