socullelement(3)

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 ()

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

SoType SoCullElement::getClassTypeId (void) [static]

This static method returns the class type.

Reimplemented from SoElement.

int SoCullElement::getClassStackIndex (void) [static]

This static method returns the state stack index for the class.

Reimplemented from SoElement.

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::initClass (void) [static]

Initialize relevant common data for all instances, like the type
system.

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

SbBool transform = 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

SbBool transform = 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.

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.

Version 3.1.0 15 Jun 2009 SoCullElement(3)