Ubuntu Manpage: SoLevelOfDetail — level-of-detail switching group node

name
inherits from
synopsis
description
fields
methods
action behavior
file format/defaults
see also

Provided by: inventor-doc_2.1.5-10-18_all

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
     }