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

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
     }