NAME

SoLevelOfDetail — level-of-detail switching group node

INHERITS FROM

SoBase > SoFieldContainer > SoNode > SoGroup > SoLevelOfDetail

SYNOPSIS

#include <Inventor/nodes/SoLevelOfDetail.h>

Fields from class SoLevelOfDetail:

SoMFFloat screenArea

Methods from class SoLevelOfDetail:

SoLevelOfDetail()

static SoType getClassTypeId()

Methods from class SoGroup:

void addChild(SoNode *child)

void insertChild(SoNode *child, int newChildIndex)

SoNode * getChild(int index) const

int findChild(const SoNode *child) const

int getNumChildren() const

void removeChild(int index)

void removeChild(SoNode *child)

void removeAllChildren()

void replaceChild(int index, SoNode *newChild)

void replaceChild(SoNode *oldChild, SoNode *newChild)

Methods from class SoNode:

void setOverride(SbBool state)

SbBool isOverride() const

SoNode * copy(SbBool copyConnections = FALSE) const

virtual SbBool affectsState() const

static SoNode * getByName(const SbName &name)

static int getByName(const SbName &name, SoNodeList &list)

Methods from class SoFieldContainer:

void setToDefaults()

SbBool hasDefaultValues() const

SbBool fieldsAreEqual(const SoFieldContainer *fc) const

void copyFieldValues(const SoFieldContainer *fc, SbBool copyConnections = FALSE)

SbBool set(const char *fieldDataString)

void get(SbString &fieldDataString)

virtual int getFields(SoFieldList &resultList) const

virtual SoField * getField(const SbName &fieldName) const

SbBool getFieldName(const SoField *field, SbName &fieldName) const

SbBool isNotifyEnabled() const

SbBool enableNotify(SbBool flag)

Methods from class SoBase:

void ref()

void unref() const

void unrefNoDelete() const

void touch()

virtual SoType getTypeId() const

SbBool isOfType(SoType type) const

virtual void setName(const SbName &name)

virtual SbName getName() const

DESCRIPTION

The children of this node typically represent the same object or objects at varying levels of detail, from highest detail to lowest. The size of the objects when projected into the viewport is used to determine which version to use (i.e., which child to traverse).

The size is computed as the area of the screen rectangle enclosing the projection of the 3D bounding box that encloses all of the children. When rendering, this size is compared to the values in the screenArea field. If the size is greater than the first value, child 0 is traversed. If it is smaller than the first, but greater than the second, child 1 is traversed, and so on. If there are fewer children than are required by this rule, the last child is traversed. The screenArea field contains just 0 by default, so the first child is always traversed.

The size calculation takes the current complexity into account. If the complexity is 0 or is of type BOUNDING_BOX, the last child is always traversed. If the complexity is less than .5, the computed size is scaled down appropriately to use (possibly) a less detailed representation. If the complexity is greater than .5, the size is scaled up. At complexity 1, the first child is always used.

Note that the SoLOD node is similar to SoLevelOfDetail, except the switching between levels in the SoLOD node is based on distance from the camera, which is faster than using screen area.

FIELDS

SoMFFloat screenArea

Areas to use for comparison

METHODS

SoLevelOfDetail()

Creates a level-of-detail node with default settings.

static SoType getClassTypeId()

Returns type identifier for this class.

ACTION BEHAVIOR

SoGLRenderAction, SoRayPickAction, SoCallbackAction

Only the child with the appropriate level of detail is traversed.

SoGetBoundingBoxAction

The box that encloses all children is computed. (This is the box that is needed to compute the projected size.)

others

All implemented as for SoGroup.

FILE FORMAT/DEFAULTS

LevelOfDetail {


screenArea	0


}

SEE ALSO

SoLOD, SoComplexity, SoSwitch, SoGroup