SoLevelOfDetail(3IV)

NAME
     SoLevelOfDetail (SoLvlOfDtl) - level-of-detail switching group node

INHERITS FROM
     SoBase > SoFieldContainer > SoNode > SoGroup > SoLevelOfDetail

SYNOPSIS
     #include <Inventor_c/nodes/SoLevelOfDetail.h>

     typedef SoLevelOfDetail  SoLvlOfDtl

          Fields from class SoLevelOfDetail:

     SoMFFloat           screenArea

          Functions from class SoLevelOfDetail:

     SoLevelOfDetail *   SoLvlOfDtlCreate()
     SoType              SoLvlOfDtlGetClassTypeId()

          Functions from class SoGroup:

     void                SoLvlOfDtlAddChild(SoLvlOfDtl *this, SoNode *child)
     void                SoLvlOfDtlInsertChild(SoLvlOfDtl *this, SoNode
                              *child, int newChildIndex)
     SoNode *            SoLvlOfDtlGetChild(const SoLvlOfDtl *this, int index)
     int                 SoLvlOfDtlFindChild(const SoLvlOfDtl *this, const
                              SoNode *child)
     int                 SoLvlOfDtlGetNumChildren(const SoLvlOfDtl *this)
     void                SoLvlOfDtlRemoveChild(SoLvlOfDtl *this, int index)
     void                SoLvlOfDtlRemoveChildNode(SoLvlOfDtl *this, SoNode
                              *child)
     void                SoLvlOfDtlRemoveAllChildren(SoLvlOfDtl *this)
     void                SoLvlOfDtlReplaceChild(SoLvlOfDtl *this, int index,
                              SoNode *newChild)
     void                SoLvlOfDtlReplaceChildNode(SoLvlOfDtl *this, SoNode
                              *oldChild, SoNode *newChild)

          Functions from class SoNode:

     void                SoLvlOfDtlSetOverride(SoLvlOfDtl *this, SbBool state)
     SbBool              SoLvlOfDtlIsOverride(const SoLvlOfDtl *this)
     SoNode *            SoLvlOfDtlCopy(const SoLvlOfDtl *this, SbBool
                              copyConnections = FALSE)
     SbBool              SoLvlOfDtlAffectsState(const SoLvlOfDtl *this)
     SoNode *            SoLvlOfDtlGetByName(const char *name)
     int                 SoLvlOfDtlGetByNameList(const char *name, SoNodeList
                              *list)

          Functions from class SoFieldContainer:

     void                SoLvlOfDtlSetToDflts(SoLvlOfDtl *this)
     SbBool              SoLvlOfDtlHasDfltVals(const SoLvlOfDtl *this)
     SbBool              SoLvlOfDtlFldsAreEq(const SoLvlOfDtl *this, const
                              SoFieldContainer *fc)
     void                SoLvlOfDtlCopyFieldVals(SoLvlOfDtl *this, const
                              SoFieldContainer *fc, SbBool copyConnections =
                              FALSE)
     SbBool              SoLvlOfDtlSet(SoLvlOfDtl *this, const char
                              *fieldDataString)
     void                SoLvlOfDtlGet(SoLvlOfDtl *this, SbString
                              *fieldDataString)
     int                 SoLvlOfDtlGetFields(const SoLvlOfDtl *this,
                              SoFieldList *resultList)
     SoField *           SoLvlOfDtlGetField(const SoLvlOfDtl *this, const char
                              *fieldName)
     SbBool              SoLvlOfDtlGetFieldName(const SoLvlOfDtl *this, const
                              SoField *field, SbName *fieldName)
     SbBool              SoLvlOfDtlIsNotifyEnabled(const SoLvlOfDtl *this)
     SbBool              SoLvlOfDtlEnableNotify(SoLvlOfDtl *this, SbBool flag)

          Functions from class SoBase:

     void                SoLvlOfDtlRef(SoLvlOfDtl *this)
     void                SoLvlOfDtlUnref(const SoLvlOfDtl *this)
     void                SoLvlOfDtlUnrefNoDelete(const SoLvlOfDtl *this)
     void                SoLvlOfDtlTouch(SoLvlOfDtl *this)
     SoType              SoLvlOfDtlGetTypeId(const SoLvlOfDtl *this)
     SbBool              SoLvlOfDtlIsOfType(const SoLvlOfDtl *this, SoType
                              type)
     void                SoLvlOfDtlSetName(SoLvlOfDtl *this, const char *name)
     SbName              SoLvlOfDtlGetName(const SoLvlOfDtl *this)


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


FUNCTIONS
     SoLevelOfDetail *   SoLvlOfDtlCreate()
          Creates a level-of-detail node with default settings.

     SoType              SoLvlOfDtlGetClassTypeId()
          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