Provided by: libsoqt-dev-common_1.6.0~e8310f-4_amd64 bug

NAME

       SoQtRenderArea - The SoQtRenderArea class adds scenegraph handling and event management.

       The SoQtRenderArea class is a component that adds scenegraph management and input device
       event handling to the SoQtGLWidget component.

SYNOPSIS

       #include <Inventor/Qt/SoQtRenderArea.h>

       Inherits SoQtGLWidget.

       Inherited by SoQtViewer.

   Public Member Functions
       SoQtRenderArea (QWidget *parent=NULL, const char *name=NULL, SbBool embed=TRUE, SbBool
           mouseInput=TRUE, SbBool keyboardInput=TRUE)
       ~SoQtRenderArea ()
       virtual void setSceneGraph (SoNode *scene)
       virtual SoNode * getSceneGraph (void)
       void setOverlaySceneGraph (SoNode *scene)
       SoNode * getOverlaySceneGraph (void)
       void setBackgroundColor (const SbColor &color)
       const SbColor & getBackgroundColor (void) const
       void setBackgroundIndex (int idx)
       int getBackgroundIndex (void) const
       void setOverlayBackgroundIndex (int idx)
       int getOverlayBackgroundIndex (void) const
       void setColorMap (int start, int num, const SbColor *colors)
       void setOverlayColorMap (int start, int num, const SbColor *colors)
       void setViewportRegion (const SbViewportRegion &newRegion)
       const SbViewportRegion & getViewportRegion (void) const
       void setTransparencyType (SoGLRenderAction::TransparencyType type)
       SoGLRenderAction::TransparencyType getTransparencyType (void) const
       void setAntialiasing (SbBool smoothing, int numPasses)
       void getAntialiasing (SbBool &smoothing, int &numPasses) const
       void setClearBeforeRender (SbBool enable, SbBool zbEnable=TRUE)
       SbBool isClearBeforeRender (void) const
       SbBool isClearZBufferBeforeRender (void) const
       void setClearBeforeOverlayRender (SbBool enable)
       SbBool isClearBeforeOverlayRender (void) const
       void setAutoRedraw (SbBool enable)
       SbBool isAutoRedraw (void) const
       void setRedrawPriority (uint32_t priority)
       uint32_t getRedrawPriority (void) const
       void render (void)
       void renderOverlay (void)
       void scheduleRedraw (void)
       void scheduleOverlayRedraw (void)
       void redrawOnSelectionChange (SoSelection *selection)
       void redrawOverlayOnSelectionChange (SoSelection *selection)
       void setEventCallback (SoQtRenderAreaEventCB *func, void *user=NULL)
       void setSceneManager (SoSceneManager *manager)
       SoSceneManager * getSceneManager (void) const
       void setOverlaySceneManager (SoSceneManager *manager)
       SoSceneManager * getOverlaySceneManager (void) const
       void setGLRenderAction (SoGLRenderAction *action)
       SoGLRenderAction * getGLRenderAction (void) const
       void setOverlayGLRenderAction (SoGLRenderAction *action)
       SoGLRenderAction * getOverlayGLRenderAction (void) const
       SbBool sendSoEvent (const SoEvent *event)
       void registerDevice (SoQtDevice *device)
       void unregisterDevice (SoQtDevice *device)

   Static Public Member Functions
       static uint32_t getDefaultRedrawPriority (void)

   Protected Member Functions
       SoQtRenderArea (QWidget *parent, const char *name, SbBool embed, SbBool mouseInput, SbBool
           keyboardInput, SbBool build)
       virtual void redraw (void)
       virtual void actualRedraw (void)
       virtual void redrawOverlay (void)
       virtual void actualOverlayRedraw (void)
       virtual SbBool processSoEvent (const SoEvent *const event)
       virtual void processEvent (QEvent *event)
       virtual void initGraphic (void)
       virtual void initOverlayGraphic (void)
       virtual void sizeChanged (const SbVec2s &size)
       virtual void widgetChanged (QWidget *widget)
       virtual void afterRealizeHook (void)
       QWidget * buildWidget (QWidget *parent)
       virtual const char * getDefaultWidgetName (void) const
       virtual const char * getDefaultTitle (void) const
       virtual const char * getDefaultIconTitle (void) const
       virtual SbBool glScheduleRedraw (void)

   Friends
       class SoQtRenderAreaP

   Additional Inherited Members

Detailed Description

       The SoQtRenderArea class adds scenegraph handling and event management.

       The SoQtRenderArea class is a component that adds scenegraph management and input device
       event handling to the SoQtGLWidget component.

       The class has many convenient methods for controlling aspects of the rendering, like for
       instance transparency, aliasing and for scheduling of redraws.

       Native toolkit events are caught by SoQtRenderArea components, translated to Coin SoEvent
       instances and passed on to the scenegraph, in case the user is doing interactive
       operations on for instance Coin geometry draggers.

       SoQtRenderArea is the first non-abstract component in it's inheritance hierarchy that you
       can use directly from client application code to set up a scenegraph viewer canvas.

       For an SoQtRenderArea component to properly display your scenegraph, it must contain an
       SoCamera-derived node and at least one SoLight-derived lightsource node.

       Here's a complete, stand-alone example on how to set up an SoQtRenderArea with a
       scenegraph:

       #include <Inventor/Qt/SoQt.h>
       #include <Inventor/Qt/SoQtRenderArea.h>

       #include <Inventor/nodes/SoCube.h>
       #include <Inventor/nodes/SoRotor.h>
       #include <Inventor/nodes/SoArray.h>
       #include <Inventor/nodes/SoDirectionalLight.h>
       #include <Inventor/nodes/SoPerspectiveCamera.h>
       #include <Inventor/nodes/SoSeparator.h>

       // Set up a simple scenegraph, just for demonstration purposes.
       static SoSeparator *
       get_scene_graph(void)
       {
         SoSeparator * root = new SoSeparator;

         SoGroup * group = new SoGroup;

         SoRotor * rotor = new SoRotor;
         rotor->rotation = SbRotation(SbVec3f(0.2, 0.5, 0.9), M_PI/4.0);
         group->addChild(rotor);

         SoCube * cube = new SoCube;
         group->addChild(cube);

         SoArray * array = new SoArray;
         array->origin = SoArray::CENTER;
         array->addChild(group);
         array->numElements1 = 2;
         array->numElements2 = 2;
         array->separation1 = SbVec3f(4, 0, 0);
         array->separation2 = SbVec3f(0, 4, 0);

         root->addChild(array);
         return root;
       }

       int
       main(int argc, char ** argv)
       {
         QWidget * window = SoQt::init(argv[0]);

         SoSeparator * root = new SoSeparator;
         root->ref();

         SoPerspectiveCamera * camera;
         root->addChild(camera = new SoPerspectiveCamera);

         root->addChild(new SoDirectionalLight);

         SoSeparator * userroot = get_scene_graph();
         root->addChild(userroot);

         SoQtRenderArea * renderarea = new SoQtRenderArea(window);
         camera->viewAll(userroot, renderarea->getViewportRegion());
         renderarea->setSceneGraph(root);
         renderarea->setBackgroundColor(SbColor(0.0f, 0.2f, 0.3f));
         if (argc > 1) {
           renderarea->setTitle(argv[1]);
           renderarea->setIconTitle(argv[1]);
         }
         renderarea->show();

         SoQt::show(window);
         SoQt::mainLoop();

         delete renderarea;
         root->unref();

         return 0;
       }

Constructor & Destructor Documentation

   SoQtRenderArea::SoQtRenderArea (QWidget * parent = NULL, const char * name = NULL, SbBool
       embed = TRUE, SbBool mouseInput = TRUE, SbBool keyboardInput = TRUE)
       Public constructor.

   SoQtRenderArea::~SoQtRenderArea ()
       Destructor.

       References redrawOnSelectionChange(), redrawOverlayOnSelectionChange(), and
       unregisterDevice().

   SoQtRenderArea::SoQtRenderArea (QWidget * parent, const char * name, SbBool embed, SbBool
       mouseInput, SbBool keyboardInput, SbBool build) [protected]
       Protected constructor used by derived classes.

Member Function Documentation

   void SoQtRenderArea::setSceneGraph (SoNode * scene) [virtual]
       This method sets the scene graph to be rendered in the normal bitmap planes.

       See also:
           getSceneGraph(), setOverlaySceneGraph()

       Reimplemented in SoQtViewer.

   SoNode * SoQtRenderArea::getSceneGraph (void) [virtual]
       This method returns a reference to the scene graph root node as set by the user.

       See also:
           SoQtRenderArea::getSceneManager()

       Reimplemented in SoQtViewer.

   void SoQtRenderArea::setOverlaySceneGraph (SoNode * scene)
       This method sets the scene graph to render for the overlay bitmap planes.

       It will automatically take care of setting up overplay planes in the OpenGL canvas if the
       OpenGL hardware and driver supports it.

       Important note: not all graphics hardware and / or drivers for graphics hardware support
       overlay planes, so application programmers are adviced to find some other way of
       accomplishing what they want to do before resorting to using overlay planes. Using overlay
       planes will in practice severely limit the portability of applications which depend on
       them being available.

       See also:
           setSceneGraph(), getOverlaySceneGraph()

       References getOverlaySceneGraph(), and SoQtGLWidget::setOverlayRender().

   SoNode * SoQtRenderArea::getOverlaySceneGraph (void)
       This method returns the scene graph for the overlay scene.

       Referenced by glScheduleRedraw(), and setOverlaySceneGraph().

   void SoQtRenderArea::setBackgroundColor (const SbColor & color)
       This method sets the background color of the scene.

       References scheduleRedraw().

   const SbColor & SoQtRenderArea::getBackgroundColor (void) const
       This method returns the background color for the scene.

       Referenced by SoQtViewer::actualRedraw().

   void SoQtRenderArea::setBackgroundIndex (int idx)
       This method sets the index of the background color for the scene.

       References scheduleRedraw().

   int SoQtRenderArea::getBackgroundIndex (void) const
       This method returns the index of the background color for the scene.

   void SoQtRenderArea::setOverlayBackgroundIndex (int idx)
       This method sets the index of the background for the overlay scene.

       References scheduleOverlayRedraw().

   int SoQtRenderArea::getOverlayBackgroundIndex (void) const
       This method returns the index of the background for the overlay scene.

   void SoQtRenderArea::setColorMap (int start, int num, const SbColor * colors)
       This method sets the colormap for the scene.

       References scheduleRedraw().

   void SoQtRenderArea::setOverlayColorMap (int start, int num, const SbColor * colors)
       This method sets the colormap for the overlay scene.

       References scheduleOverlayRedraw().

   void SoQtRenderArea::setViewportRegion (const SbViewportRegion & region)
       This method sets the viewport region.

       References scheduleRedraw().

       Referenced by sizeChanged().

   const SbViewportRegion & SoQtRenderArea::getViewportRegion (void) const
       This method returns the viewport region.

       Referenced by SoQtConstrainedViewer::findUpDirection(), SoQtViewer::seekToPoint(),
       SoQtViewer::setSceneGraph(), and SoQtViewer::viewAll().

   void SoQtRenderArea::setTransparencyType (SoGLRenderAction::TransparencyType type)
       This method sets the transparency type to be used for the scene.

       References scheduleRedraw().

   SoGLRenderAction::TransparencyType SoQtRenderArea::getTransparencyType (void) const
       This method returns the transparency type used for the scene.

       Referenced by SoQtFullViewer::setComponentCursor().

   void SoQtRenderArea::setAntialiasing (SbBool smoothing, int numPasses)
       This method sets the antialiasing used for the scene.

       The smoothing flag signifies whether or not line and point aliasing should be turned on.
       See documentation of SoGLRenderAction::setSmoothing(), which will be called from this
       function.

       numPasses gives the number of re-renderings to do of the scene, blending together the
       results from slight 'jitters' of the camera view, into the OpenGL accumulation buffer. For
       further information, see documentation of SoGLRenderAction::setNumPasses() and
       SoQtGLWidget::setAccumulationBuffer().

       References scheduleRedraw().

   void SoQtRenderArea::getAntialiasing (SbBool & smoothing, int & numPasses) const
       This method returns the antialiasing used for the scene.

   void SoQtRenderArea::setClearBeforeRender (SbBool enable, SbBool zbEnable = TRUE)
       This method sets whether the render buffer should be cleared before rendering.

       The first argument specifies whether or not to clear out the pixels in the buffer, the
       second argument specifies whether or not the z-buffer values should be cleared between
       renderings.

       Setting the first argument to FALSE can for instance be used when you want to clear out
       the buffer yourself, for instance by drawing a background image 'under' the 3D scene
       rendered by Coin / Inventor.

       References scheduleRedraw().

   SbBool SoQtRenderArea::isClearBeforeRender (void) const
       This method returns whether the render buffer is cleared before each render.

       Referenced by SoQtViewer::actualRedraw().

   SbBool SoQtRenderArea::isClearZBufferBeforeRender (void) const
       This method returns whether the render buffer's Z buffer is cleared before each render.

       Referenced by SoQtViewer::actualRedraw().

   void SoQtRenderArea::setClearBeforeOverlayRender (SbBool enable)
       This method sets whether the overlay render buffer should be cleared before each render or
       not.

       References scheduleOverlayRedraw().

   SbBool SoQtRenderArea::isClearBeforeOverlayRender (void) const
       This method returns whether the overlay render buffer is cleared before each redraw or
       not.

   void SoQtRenderArea::setAutoRedraw (SbBool enable)
       This method sets whether redrawing should be handled automatically or not when data in the
       scenegraph changes.

       The default setting causes the renderarea to automatically trigger a redraw of the
       scenegraph contents.

   SbBool SoQtRenderArea::isAutoRedraw (void) const
       This method returns whether redrawing is handled automatically not.

   void SoQtRenderArea::setRedrawPriority (uint32_t priority)
       This method sets the redraw priority.

   uint32_t SoQtRenderArea::getRedrawPriority (void) const
       This method returns the redraw priority.

   uint32_t SoQtRenderArea::getDefaultRedrawPriority (void) [static]
       This function returns the default redraw priority.

   void SoQtRenderArea::render (void)
       This method causes the immediate rendering of the scene, by calling
       SoQtRenderArea::redraw().

       References redraw().

   void SoQtRenderArea::renderOverlay (void)
       This method renders the overlay scene.

       References redrawOverlay().

   void SoQtRenderArea::scheduleRedraw (void)
       This method schedules a redraw to happen at a later time (when the application has
       processed it's other events first).

       Referenced by SoQtFlyViewer::actualRedraw(), SoQtExaminerViewer::actualRedraw(),
       glScheduleRedraw(), SoQtViewer::setAnaglyphStereoColorMasks(), setAntialiasing(),
       SoQtViewer::setAutoClipping(), SoQtViewer::setAutoClippingStrategy(),
       setBackgroundColor(), setBackgroundIndex(), setClearBeforeRender(), setColorMap(),
       SoQtExaminerViewer::setFeedbackSize(), SoQtExaminerViewer::setFeedbackVisibility(),
       SoQtViewer::setStereoOffset(), SoQtViewer::setStereoViewing(), setTransparencyType(),
       SoQtFlyViewer::setViewing(), setViewportRegion(), and
       SoQtViewer::setWireframeOverlayColor().

   void SoQtRenderArea::scheduleOverlayRedraw (void)
       This method schedules a redraw of the overlay scene.

       Referenced by glScheduleRedraw(), setClearBeforeOverlayRender(),
       setOverlayBackgroundIndex(), and setOverlayColorMap().

   void SoQtRenderArea::redrawOnSelectionChange (SoSelection * selection)
       Do automatic redraw of the scenegraph when a selection under the SoSelection node is
       changed.

       Pass NULL to deactivate.

       (Only one SoSelection node can be monitored at any given time. This is obviously a rather
       silly design flaw. We choose to match the original Inventor API here, but this will
       probably change in the next major revision of the library.)

       Referenced by ~SoQtRenderArea().

   void SoQtRenderArea::redrawOverlayOnSelectionChange (SoSelection * selection)
       Do automatic redraw of the scenegraph in the overlay planes when a selection under the
       SoSelection node is changed.

       Pass NULL to deactivate.

       See also:
           SoQtRenderArea::redrawOnSelectionChange()

       Referenced by ~SoQtRenderArea().

   void SoQtRenderArea::setEventCallback (SoQtRenderAreaEventCB * func, void * user = NULL)
       This method sets the render area event callback.

   void SoQtRenderArea::setSceneManager (SoSceneManager * manager)
       This method sets the normal scene SoSceneManager object.

       The previous set scene manager is deleted, and there is no way to currently avoid that.
       This might change in the future.

       References SoQtGLWidget::getGLSize().

   SoSceneManager * SoQtRenderArea::getSceneManager (void) const
       This method returns the normal scene SoSceneManager object.

       Having a reference to the SoSceneManager instance is useful for getting at the real root
       node of the rendering scenegraph, including camera, headlight and miscellaneous drawstyle
       nodes. The getSceneGraph() method will only return the user scenegrah for SoQtRenderArea
       subclass SoQtViewer and further subclasses. The reason this is not always what you want is
       because certain actions (like the SoRayPickAction) needs to traverse a valid camera if it
       should work as expected.

       If you need to get a pointer to the real root node use this method to get the
       SoSceneManager instance reference used by the SoQtRenderArea, then use
       SoSceneManager::getSceneGraph() to get the root node Coin uses for rendering.

       Referenced by SoQtViewer::actualRedraw(), SoQtConstrainedViewer::findUpDirection(), and
       initGraphic().

   void SoQtRenderArea::setOverlaySceneManager (SoSceneManager * manager)
       This method sets the overlay scene SoSceneManager object.

       The previous set scene manager is not freed and will leak unless the user frees it.

       References SoQtGLWidget::getGLSize().

   SoSceneManager * SoQtRenderArea::getOverlaySceneManager (void) const
       This method returns the overlay scene SoSceneManager object.

       Referenced by initOverlayGraphic().

   void SoQtRenderArea::setGLRenderAction (SoGLRenderAction * action)
       This method sets the SoGLRenderAction object for the normal scene.

       References SoQtComponent::getSize(), and sizeChanged().

   SoGLRenderAction * SoQtRenderArea::getGLRenderAction (void) const
       This method returns the SoGLRenderAction object for the normal scene.

       Referenced by SoQtViewer::setViewing().

   void SoQtRenderArea::setOverlayGLRenderAction (SoGLRenderAction * action)
       This method sets the SoGLRenderAction object for rendering the overlay scenegraph.

   SoGLRenderAction * SoQtRenderArea::getOverlayGLRenderAction (void) const
       This method returns the SoGLRenderAction object for the overlay scene graph.

   SbBool SoQtRenderArea::sendSoEvent (const SoEvent * event)
       This method posts and processes an SoEvent object to the SoQtRenderArea-based component
       and returns the result value from the event handler. This is a synchronous operation.

       References processSoEvent().

   void SoQtRenderArea::registerDevice (SoQtDevice * device)
       This method adds device to the list of devices handling events for this component.

       References SoQtDevice::enable(), SoQtGLWidget::getGLSize(), SoQtGLWidget::getGLWidget(),
       and SoQtDevice::setWindowSize().

       Referenced by afterRealizeHook().

   void SoQtRenderArea::unregisterDevice (SoQtDevice * device)
       This method removes device from the list of devices handling events for this component.

       References SoQtDevice::disable(), and SoQtGLWidget::getGLWidget().

       Referenced by ~SoQtRenderArea().

   void SoQtRenderArea::redraw (void) [protected],  [virtual]
       This method is called from the render() method and takes care of setting up the context
       for OpenGL rendering (by making the OpenGL canvas the current context and specifying
       either the front or back buffer for rendering, depending on whether we're in singlebuffer
       or doublebuffer mode).

       After setting up the OpenGL context, it calls actualRedraw() for the actual scenegraph
       rendering to take place.

       Finally, the OpenGL buffers are either swapped back-to-front (for doublebuffering) or
       flushed (for singlebuffering), and our OpenGL context is unlocked.

       The application programmer may override this method if extreme low-level control of the
       rendering process is necessary. Usually, you should be able to get away with overriding
       actualRedraw() for special cases, though.

       Implements SoQtGLWidget.

       References actualRedraw(), SoQtGLWidget::glFlushBuffer(), SoQtGLWidget::glLockNormal(),
       SoQtGLWidget::glSwapBuffers(), SoQtGLWidget::glUnlockNormal(),
       SoQtGLWidget::hasNormalGLArea(), SoQtGLWidget::isDoubleBuffer(),
       SoQtGLWidget::isDrawToFrontBufferEnable(), SoQtComponent::isVisible(), and
       SoQtGLWidget::waitForExpose.

       Referenced by render().

   void SoQtRenderArea::actualRedraw (void) [protected],  [virtual]
       This method instantly redraws the normal (non-overlay) scenegraph by calling
       SoSceneManager::render().

       Subclasses may override this method to add their own rendering before or after Coin
       renders it's scenegraph.

       The following is a complete example that demonstrates one way of adding both a background
       image and foreground (overlay) geometry to the 'normal' rendering:

       // This example shows how to put a permanent background image on
       // your viewer canvas, below the 3D graphics, plus overlay
       // foreground geometry.  Written by mortene.
       // Copyright Kongsberg Oil & Gas Technologies 2002.

       // *************************************************************************

       #include <Inventor/Qt/SoQt.h>
       #include <Inventor/Qt/viewers/SoQtExaminerViewer.h>
       #include <Inventor/nodes/SoBaseColor.h>
       #include <Inventor/nodes/SoCone.h>
       #include <Inventor/nodes/SoCube.h>
       #include <Inventor/nodes/SoImage.h>
       #include <Inventor/nodes/SoLightModel.h>
       #include <Inventor/nodes/SoOrthographicCamera.h>
       #include <Inventor/nodes/SoRotationXYZ.h>
       #include <Inventor/nodes/SoSeparator.h>
       #include <Inventor/nodes/SoTranslation.h>

       #include <GL/gl.h>

       // *************************************************************************

       class MyExaminerViewer : public SoQtExaminerViewer {

       public:
         MyExaminerViewer(QWidget * parent, const char * filename);
         ~MyExaminerViewer();

       protected:
         virtual void actualRedraw(void);

       private:
         SoSeparator * bckgroundroot;
         SoSeparator * foregroundroot;
         SoRotationXYZ * arrowrotation;
       };

       MyExaminerViewer::MyExaminerViewer(QWidget * parent, const char * filename)
         : SoQtExaminerViewer(parent)
       {
         // Coin should not clear the pixel-buffer, so the background image
         // is not removed.
         this->setClearBeforeRender(FALSE, TRUE);

         // Set up background scenegraph with image in it.

         this->bckgroundroot = new SoSeparator;
         this->bckgroundroot->ref();

         SoOrthographicCamera * cam = new SoOrthographicCamera;
         cam->position = SbVec3f(0, 0, 1);
         cam->height = 1;
         // SoImage will be at z==0.0.
         cam->nearDistance = 0.5;
         cam->farDistance = 1.5;

         SoImage * img = new SoImage;
         img->vertAlignment = SoImage::HALF;
         img->horAlignment = SoImage::CENTER;
         img->filename = filename;

         this->bckgroundroot->addChild(cam);
         this->bckgroundroot->addChild(img);

         // Set up foreground, overlayed scenegraph.

         this->foregroundroot = new SoSeparator;
         this->foregroundroot->ref();

         SoLightModel * lm = new SoLightModel;
         lm->model = SoLightModel::BASE_COLOR;

         SoBaseColor * bc = new SoBaseColor;
         bc->rgb = SbColor(1, 1, 0);

         cam = new SoOrthographicCamera;
         cam->position = SbVec3f(0, 0, 5);
         cam->height = 10;
         cam->nearDistance = 0;
         cam->farDistance = 10;

         const double ARROWSIZE = 2.0;

         SoTranslation * posit = new SoTranslation;
         posit->translation = SbVec3f(-2.5 * ARROWSIZE, 1.5 * ARROWSIZE, 0);

         arrowrotation = new SoRotationXYZ;
         arrowrotation->axis = SoRotationXYZ::Z;

         SoTranslation * offset = new SoTranslation;
         offset->translation = SbVec3f(ARROWSIZE/2.0, 0, 0);

         SoCube * cube = new SoCube;
         cube->width = ARROWSIZE;
         cube->height = ARROWSIZE/15.0;

         this->foregroundroot->addChild(cam);
         this->foregroundroot->addChild(lm);
         this->foregroundroot->addChild(bc);
         this->foregroundroot->addChild(posit);
         this->foregroundroot->addChild(arrowrotation);
         this->foregroundroot->addChild(offset);
         this->foregroundroot->addChild(cube);
       }

       MyExaminerViewer::~MyExaminerViewer()
       {
         this->bckgroundroot->unref();
         this->foregroundroot->unref();
       }

       void
       MyExaminerViewer::actualRedraw(void)
       {
         // Must set up the OpenGL viewport manually, as upon resize
         // operations, Coin won't set it up until the SoGLRenderAction is
         // applied again. And since we need to do glClear() before applying
         // the action..
         const SbViewportRegion vp = this->getViewportRegion();
         SbVec2s origin = vp.getViewportOriginPixels();
         SbVec2s size = vp.getViewportSizePixels();
         glViewport(origin[0], origin[1], size[0], size[1]);

         const SbColor col = this->getBackgroundColor();
         glClearColor(col[0], col[1], col[2], 0.0f);
         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

         // Render our scenegraph with the image.
         SoGLRenderAction * glra = this->getGLRenderAction();
         glra->apply(this->bckgroundroot);

         // Render normal scenegraph.
         SoQtExaminerViewer::actualRedraw();

         // Increase arrow angle with 1/1000 ° every frame.
         arrowrotation->angle = arrowrotation->angle.getValue() + (0.001 / M_PI * 180);
         // Render overlay front scenegraph.
         glClear(GL_DEPTH_BUFFER_BIT);
         glra->apply(this->foregroundroot);
       }

       // *************************************************************************

       int
       main(int argc, char ** argv)
       {
         if (argc != 2) {
           (void)fprintf(stderr, "0sage: %s <image-filename>0, argv[0]);
           exit(1);
         }

         QWidget * window = SoQt::init(argv[0]);

         MyExaminerViewer * viewer = new MyExaminerViewer(window, argv[1]);

         viewer->setSceneGraph(new SoCone);
         viewer->show();

         SoQt::show(window);
         SoQt::mainLoop();

         delete viewer;
         return 0;
       }

       // *************************************************************************

       Reimplemented in SoQtViewer, SoQtExaminerViewer, SoQtFlyViewer, and SoQtPlaneViewer.

       References SoQtComponent::isVisible().

       Referenced by redraw().

   void SoQtRenderArea::redrawOverlay (void) [protected],  [virtual]
       This method redraws the overlay scene.

       Reimplemented from SoQtGLWidget.

       References actualOverlayRedraw(), SoQtGLWidget::glFlushBuffer(),
       SoQtGLWidget::glLockOverlay(), SoQtGLWidget::glUnlockOverlay(),
       SoQtGLWidget::hasOverlayGLArea(), SoQtComponent::isVisible(), and
       SoQtGLWidget::waitForExpose.

       Referenced by renderOverlay().

   void SoQtRenderArea::actualOverlayRedraw (void) [protected],  [virtual]
       This method renders the overlay scene.

       References SoQtComponent::isVisible().

       Referenced by redrawOverlay().

   SbBool SoQtRenderArea::processSoEvent (const SoEvent *const event) [protected],  [virtual]
       Toolkit-native events are attempted converted to Coin-generic events in the
       SoQtRenderArea::processEvent() method. If this succeeds, they are forwarded to this
       method.

       This is a virtual method, and is overridden in it's subclasses to catch events of
       particular interest to the viewer classes, for instance.

       Return TRUE iff the event was processed. If not it should be passed on further up in the
       inheritance hierarchy by the caller. This last point is extremely important to take note
       of if you are expanding the toolkit with your own viewer class.

       This method is not part of the original SGI InventorXt API. Note that you can still
       override the toolkit-native processEvent() method instead of this 'generic' method.

       Reimplemented in SoQtViewer, SoQtFullViewer, SoQtExaminerViewer, SoQtFlyViewer, and
       SoQtPlaneViewer.

       Referenced by processEvent(), and sendSoEvent().

   void SoQtRenderArea::processEvent (QEvent * event) [protected],  [virtual]
       Overrides SoQtGLWidget::processEvent() to attempt to convert toolkit-native events to
       Coin-generic events. If this succeeds, the generic SoEvent is forwarded to
       SoQtRenderArea::processSoEvent().

       Reimplemented from SoQtGLWidget.

       References SoQtGLWidget::glLockNormal(), SoQtGLWidget::glUnlockNormal(), and
       processSoEvent().

   void SoQtRenderArea::initGraphic (void) [protected],  [virtual]
       This method is invoked to initialize the normal graphics.

       Reimplemented from SoQtGLWidget.

       References getSceneManager(), and SoQtGLWidget::isRGBMode().

   void SoQtRenderArea::initOverlayGraphic (void) [protected],  [virtual]
       This method is invoked to initialize the overlay graphics.

       Reimplemented from SoQtGLWidget.

       References getOverlaySceneManager().

   void SoQtRenderArea::sizeChanged (const SbVec2s & size) [protected],  [virtual]
       Called internally from within the SoQt library when the widget embedded in a component
       changes it size, which is usually triggered by end-user interaction.

       This method is then invoked to notify the component that the size has changed. It is
       called from the top and all the way down to the bottom, the size being adjusted to take
       into account extra decorations having been added at each level in the component class
       hierarchy.

       Reimplemented from SoQtGLWidget.

       Reimplemented in SoQtViewer, and SoQtFullViewer.

       References SoQtObject::getClassTypeId(), SoQtGLWidget::getGLSize(),
       SoQtObject::getTypeId(), SoQtGLWidget::setGLSize(), and setViewportRegion().

       Referenced by setGLRenderAction().

   void SoQtRenderArea::widgetChanged (QWidget * w) [protected],  [virtual]
       This is the method which gets called whenever we change which OpenGL widget is used.

       Should be overridden in subclasses which directly or indirectly store the return value
       from the SoQtGLWidget::getGLWidget() method.

       See also:
           sizeChanged()

       Reimplemented from SoQtGLWidget.

       References SoQtDevice::enable(), SoQtGLWidget::getGLWidget(), and
       SoQtGLWidget::isRGBMode().

   void SoQtRenderArea::afterRealizeHook (void) [protected],  [virtual]
       A function 'hook' / callback invoked just after the window for the component has been
       realized.

       Override this if you need specific initialization for your own component or viewer class
       to happen right after it has been made visible, but remember to call upwards in the
       inheritance hierarchy:

       void
       MyLittleViewer::afterRealizeHook(void)
       {
         <superclass>::afterRealizeHook();
         // [own initialization here]
       }

       Reimplemented from SoQtComponent.

       Reimplemented in SoQtExaminerViewer, SoQtPlaneViewer, and SoQtFlyViewer.

       References registerDevice().

   const char * SoQtRenderArea::getDefaultWidgetName (void) const [protected],  [virtual]
       This method returns the default name of a component widget class.

       It should be overridden by derived non-abstract classes for the topmost widget in the
       component to have a proper name.

       Reimplemented from SoQtComponent.

       Reimplemented in SoQtExaminerViewer, SoQtFlyViewer, and SoQtPlaneViewer.

   const char * SoQtRenderArea::getDefaultTitle (void) const [protected],  [virtual]
       This method returns the default window caption string of the component.

       It should be overridden by derived non-abstract classes so the window and popup menu will
       get a proper title.

       Reimplemented from SoQtComponent.

       Reimplemented in SoQtExaminerViewer, SoQtFlyViewer, and SoQtPlaneViewer.

   const char * SoQtRenderArea::getDefaultIconTitle (void) const [protected],  [virtual]
       This method returns the default icon title of the component.

       It should be overridden by derived non-abstract classes so icons will get proper titles.

       Reimplemented from SoQtComponent.

       Reimplemented in SoQtExaminerViewer, SoQtFlyViewer, and SoQtPlaneViewer.

   SbBool SoQtRenderArea::glScheduleRedraw (void) [protected],  [virtual]
       Will be called whenever scene graph needs to be redrawn. If this method return FALSE,
       redraw() will be called immediately.

       Default method simply returns FALSE. Override this method to schedule a redraw and return
       TRUE if you're trying to do The Right Thing.

       Reimplemented from SoQtGLWidget.

       References getOverlaySceneGraph(), SoQtGLWidget::hasOverlayGLArea(),
       scheduleOverlayRedraw(), and scheduleRedraw().

Author

       Generated automatically by Doxygen for SoQt from the source code.