NAME

       SoCullElement -

       The SoCullElement class is used internally for render and pick culling.

       The element holds all planes the geometry should be inside, and keeps a bitflag to signal
       which planes need to be tested.

SYNOPSIS

       #include <Inventor/elements/SoCullElement.h>

       Inherits SoElement.

   Public Member Functions
       virtual void init (SoState *state)
       virtual void push (SoState *state)
       virtual SbBool matches (const SoElement *elt) const
       virtual SoElement * copyMatchInfo (void) const

   Static Public Member Functions
       static SoType getClassTypeId (void)
       static int getClassStackIndex (void)
       static void * createInstance (void)
       static void initClass (void)
       static void setViewVolume (SoState *state, const SbViewVolume &vv)
       static void addPlane (SoState *state, const SbPlane &newplane)
       static SbBool cullBox (SoState *state, const SbBox3f &box, const SbBool transform=TRUE)
       static SbBool cullTest (SoState *state, const SbBox3f &box, const SbBool transform=TRUE)
       static SbBool completelyInside (SoState *state)

   Protected Member Functions
       virtual ~SoCullElement ()

   Additional Inherited Members

Detailed Description

       The SoCullElement class is used internally for render and pick culling.

       The element holds all planes the geometry should be inside, and keeps a bitflag to signal
       which planes need to be tested.

       This element is an extension for Coin, and is not available in the original Open Inventor.

       The maximum number of planes in this element is 32, which should be more than enough,
       since the view frustum is represented by 6 planes, and the maximum number of OpenGL
       clipping planes is typically 6 or 8.

       This element is designed for fast culling, and will not do optimal view frustum culling; a
       box might not be culled even though it is outside the view frustum. The assumption is that
       the view frustum is small compared to the world model. The element simply records all
       planes to be culled against, and the graph is not culled until it is completely outside
       one of the planes.

       SoCullElement is not active for other actions than SoGLRenderAction. It's possible to
       enable it for SoCallbackAction by updating it in a post camera callback though. Do
       something like this:

       static SoCallbackAction::Response
       camera_cb(void * data, SoCallbackAction * action, const SoNode * node)
       {
         SoState * state = action->getState();
         SoCullElement::setViewVolume(state, SoViewVolumeElement::get(state));
         return SoCallbackAction::CONTINUE;
       }

       [...]
       SoCallbackAction cba(myviewport);
       cba.addPostCallback(SoCamera::getClassTypeId(), camera_cb, NULL);.fi

       When the view volume is set in SoCullElement in the post camera callback, SoCallbackAction will perform culling on Separators and other nodes in the same way as SoGLRenderAction.

Constructor & Destructor Documentation

   SoCullElement::~SoCullElement () [protected],  [virtual]
       The destructor.

Member Function Documentation

   void * SoCullElement::createInstance (void) [static]
       This API member is considered internal to the library, as it is not likely to be of
       interest to the application programmer.

   void SoCullElement::init (SoState *state) [virtual]
       This function initializes the element type in the given SoState. It is called for the
       first element of each enabled element type in SoState objects.

       Reimplemented from SoElement.

   void SoCullElement::push (SoState *state) [virtual]
       This method is called every time a new element is required in one of the stacks. This
       happens when a writable element is requested, using SoState::getElement() or indirectly
       SoElement::getElement(), and the depth of the current element is less than the state
       depth.

       Override this method if your element needs to copy data from the previous top of stack.
       The push() method is called on the new element, and the previous element can be found
       using SoElement::getNextInStack().

       Reimplemented from SoElement.

   void SoCullElement::setViewVolume (SoState *state, const SbViewVolume &vv) [static]
       Sets the current view volume. In effect, this adds six planes to the list of culling
       planes. If a view volume has already been set, the old view volume planes are overwritten
       by the new ones. The view volume must be in the world coordinate systems.

   void SoCullElement::addPlane (SoState *state, const SbPlane &newplane) [static]
       Add plane geometry must be inside. The plane must be in the world coordinate system.

   SbBool SoCullElement::cullBox (SoState *state, const SbBox3f &box, const SbBooltransform =
       TRUE) [static]
       Cull against box. If transform is TRUE, the box is assumed to be in object space, and will
       be transformed into world space using the model matrix. Returns TRUE if box is outside one
       of the planes, and updates the element to detect when geometry is completely inside all
       planes.

   SbBool SoCullElement::cullTest (SoState *state, const SbBox3f &box, const SbBooltransform =
       TRUE) [static]
       Cull against box. If transform is TRUE, the box is assumed to be in object space, and will
       be transformed into world space using the model matrix. Returns TRUE if box is outside one
       of the planes. This method will not update the element state, just perform a cull test
       against active planes.

   SbBool SoCullElement::completelyInside (SoState *state) [static]
       Returns TRUE if the current geometry is completely inside all planes. There is no need to
       do a cull test if this is the case.

   SbBool SoCullElement::matches (const SoElement *element) const [virtual]
       This function returns TRUE is the element matches another element (of the same class),
       with respect to cache validity.

       If the application programmer's extension element has a matches() function, it should also
       have a copyMatchInfo() function.

       Implements SoElement.

   SoElement * SoCullElement::copyMatchInfo (void) const [virtual]
       This function creates a copy of the element that contains enough information to enable the
       matches() function to work.

       Used to help with scenegraph traversal caching operations.

       Implements SoElement.

Author

       Generated automatically by Doxygen for Coin from the source code.