SoLOD Class Reference

The SoLOD class is used to choose a child based distance between viewer and object.The class documentation for the SoLOD node class would be similar enough to that of SoLevelOfDetail that we will refer you to look at that one first. It will explain the general principles of what a level-of-detail mechanism is, and why and how to use it. More...

#include <Inventor/nodes/SoLOD.h>

Inheritance diagram for SoLOD:

Public Member Functions
virtual SoType	getTypeId (void) const
	Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and "downward" casting. More...
	SoLOD (void)
	SoLOD (int numchildren)
virtual void	doAction (SoAction *action)
virtual void	callback (SoCallbackAction *action)
virtual void	GLRender (SoGLRenderAction *action)
virtual void	GLRenderBelowPath (SoGLRenderAction *action)
virtual void	GLRenderInPath (SoGLRenderAction *action)
virtual void	GLRenderOffPath (SoGLRenderAction *action)
virtual void	rayPick (SoRayPickAction *action)
virtual void	getBoundingBox (SoGetBoundingBoxAction *action)
virtual void	getPrimitiveCount (SoGetPrimitiveCountAction *action)
virtual void	audioRender (SoAudioRenderAction *action)
virtual void	notify (SoNotList *nl)
Public Member Functions inherited from SoGroup
	SoGroup (void)
	SoGroup (int nchildren)
virtual void	addChild (SoNode *node)
virtual void	insertChild (SoNode *child, int newchildindex)
virtual SoNode *	getChild (int index) const
virtual int	findChild (const SoNode *node) const
virtual int	getNumChildren (void) const
virtual void	removeChild (int childindex)
virtual void	removeChild (SoNode *child)
virtual void	removeAllChildren (void)
virtual void	replaceChild (int index, SoNode *newchild)
virtual void	replaceChild (SoNode *oldchild, SoNode *newchild)
virtual void	getMatrix (SoGetMatrixAction *action)
virtual void	handleEvent (SoHandleEventAction *action)
virtual void	pick (SoPickAction *action)
virtual void	search (SoSearchAction *action)
virtual void	write (SoWriteAction *action)
virtual SoChildList *	getChildren (void) const
Public Member Functions inherited from SoNode
void	setOverride (const SbBool state)
SbBool	isOverride (void) const
void	setNodeType (const NodeType type)
NodeType	getNodeType (void) const
virtual SoNode *	copy (SbBool copyconnections=FALSE) const
virtual SbBool	affectsState (void) const
virtual void	grabEventsSetup (void)
virtual void	grabEventsCleanup (void)
virtual void	startNotify (void)
uint32_t	getNodeId (void) const
virtual void	writeInstance (SoOutput *out)
virtual SoNode *	addToCopyDict (void) const
virtual SoFieldContainer *	copyThroughConnection (void) const
Public Member Functions inherited from SoFieldContainer
void	setToDefaults (void)
SbBool	hasDefaultValues (void) const
SbBool	fieldsAreEqual (const SoFieldContainer *container) const
void	copyFieldValues (const SoFieldContainer *container, SbBool copyconnections=FALSE)
SbBool	set (const char *const fielddata)
void	get (SbString &fielddata)
virtual int	getFields (SoFieldList &l) const
virtual int	getAllFields (SoFieldList &l) const
virtual SoField *	getField (const SbName &name) const
virtual SoField *	getEventIn (const SbName &name) const
virtual SoField *	getEventOut (const SbName &name) const
SbBool	getFieldName (const SoField *const field, SbName &name) const
SbBool	enableNotify (const SbBool flag)
SbBool	isNotifyEnabled (void) const
SbBool	set (const char *fielddata, SoInput *input)
void	get (SbString &fielddata, SoOutput *out)
virtual SbBool	validateNewFieldValue (SoField *field, void *newval)
virtual void	addWriteReference (SoOutput *out, SbBool isfromfield=FALSE)
SbBool	getIsBuiltIn (void) const
virtual void	getFieldsMemorySize (size_t &managed, size_t &unmanaged) const
void	setUserData (void *userdata) const
void *	getUserData (void) const
Public Member Functions inherited from SoBase
void	ref (void) const
void	unref (void) const
void	unrefNoDelete (void) const
int32_t	getRefCount (void) const
void	touch (void)
SbBool	isOfType (SoType type) const
	Returns TRUE if the type of this object is either of the same type or inherited from type. More...
virtual SbName	getName (void) const
virtual void	setName (const SbName &newname)
void	addAuditor (void *const auditor, const SoNotRec::Type type)
void	removeAuditor (void *const auditor, const SoNotRec::Type type)
const SoAuditorList &	getAuditors (void) const
SbBool	shouldWrite (void)
void	assertAlive (void) const

Static Public Member Functions
static SoType	getClassTypeId (void)
static void	initClass (void)
Static Public Member Functions inherited from SoGroup
static SoType	getClassTypeId (void)
static void	initClass (void)
Static Public Member Functions inherited from SoNode
static uint32_t	getCompatibilityTypes (const SoType &nodetype)
static SoType	getClassTypeId (void)
static SoNode *	getByName (const SbName &name)
static int	getByName (const SbName &name, SoNodeList &l)
static void	initClass (void)
static void	initClasses (void)
static uint32_t	getNextNodeId (void)
static int	getActionMethodIndex (const SoType type)
static void	getBoundingBoxS (SoAction *action, SoNode *node)
static void	GLRenderS (SoAction *action, SoNode *node)
static void	callbackS (SoAction *action, SoNode *node)
static void	getMatrixS (SoAction *action, SoNode *node)
static void	handleEventS (SoAction *action, SoNode *node)
static void	pickS (SoAction *action, SoNode *node)
static void	rayPickS (SoAction *action, SoNode *node)
static void	searchS (SoAction *action, SoNode *node)
static void	writeS (SoAction *action, SoNode *node)
static void	audioRenderS (SoAction *action, SoNode *node)
static void	getPrimitiveCountS (SoAction *action, SoNode *node)
Static Public Member Functions inherited from SoFieldContainer
static void	initClass (void)
static SoType	getClassTypeId (void)
static void	cleanupClass (void)
static void	initCopyDict (void)
static void	addCopy (const SoFieldContainer *orig, const SoFieldContainer *copy)
static SoFieldContainer *	checkCopy (const SoFieldContainer *orig)
static SoFieldContainer *	findCopy (const SoFieldContainer *orig, const SbBool copyconnections)
static void	copyDone (void)
Static Public Member Functions inherited from SoBase
static void	initClass (void)
	Sets up initialization for data common to all instances of this class, like submitting necessary information to the Coin type system.
static SoType	getClassTypeId (void)
	This static method returns the SoType object associated with objects of this class.
static void	addName (SoBase *const base, const char *const name)
static void	removeName (SoBase *const base, const char *const name)
static void	incrementCurrentWriteCounter (void)
static void	decrementCurrentWriteCounter (void)
static SoBase *	getNamedBase (const SbName &name, SoType type)
static int	getNamedBases (const SbName &name, SoBaseList &baselist, SoType type)
static SbBool	read (SoInput *input, SoBase *&base, SoType expectedtype)
static void	setInstancePrefix (const SbString &c)
static void	setTraceRefs (SbBool trace)
static SbBool	getTraceRefs (void)
static SbBool	connectRoute (SoInput *input, const SbName &fromnodename, const SbName &fromfieldname, const SbName &tonodename, const SbName &tofieldname)
static SbBool	readRoute (SoInput *input)

Public Attributes
SoMFFloat	range
SoSFVec3f	center

Protected Member Functions
virtual const SoFieldData *	getFieldData (void) const
virtual	~SoLOD ()
virtual int	whichToTraverse (SoAction *)
Protected Member Functions inherited from SoGroup
virtual	~SoGroup ()
virtual SbBool	readInstance (SoInput *in, unsigned short flags)
virtual SbBool	readChildren (SoInput *in)
virtual void	copyContents (const SoFieldContainer *from, SbBool copyconnections)
virtual SoNotRec	createNotRec (void)
void	setOperation (const SoNotRec::OperationType opType=SoNotRec::UNSPECIFIED, const SoNode *cc=NULL, const SoNode *pc=NULL, const int ci=-1)
Protected Member Functions inherited from SoNode
	SoNode (void)
virtual	~SoNode ()
Protected Member Functions inherited from SoFieldContainer
	SoFieldContainer (void)
virtual	~SoFieldContainer ()
Protected Member Functions inherited from SoBase
	SoBase (void)
virtual	~SoBase ()
virtual void	destroy (void)
SbBool	hasMultipleWriteRefs (void) const
SbBool	writeHeader (SoOutput *out, SbBool isgroup, SbBool isengine) const
void	writeFooter (SoOutput *out) const
virtual const char *	getFileFormatName (void) const

Static Protected Member Functions
static const SoFieldData **	getFieldDataPtr (void)
Static Protected Member Functions inherited from SoGroup
static const SoFieldData **	getFieldDataPtr (void)
Static Protected Member Functions inherited from SoNode
static const SoFieldData **	getFieldDataPtr (void)
static void	setNextActionMethodIndex (int index)
static int	getNextActionMethodIndex (void)
static void	incNextActionMethodIndex (void)
static void	setCompatibilityTypes (const SoType &nodetype, const uint32_t bitmask)
Static Protected Member Functions inherited from SoBase
static uint32_t	getCurrentWriteCounter (void)
static void	staticDataLock (void)
static void	staticDataUnlock (void)

Additional Inherited Members
Public Types inherited from SoNode
enum	NodeType {   INVENTOR = 0x0000, VRML1 = 0x0001, VRML2 = 0x0002, INVENTOR_1 = 0x0004,   INVENTOR_2_0 = 0x0008, INVENTOR_2_1 = 0x0010, INVENTOR_2_5 = 0x0020, INVENTOR_2_6 = 0x0040,   COIN_1_0 = 0x0080, COIN_2_0 = 0x0100, EXTENSION = 0x0200, COIN_2_2 = 0x0400,   COIN_2_3 = 0x0800, COIN_2_4 = 0x1000, INVENTOR_5_0 = 0x2000, COIN_2_5 = 0x4000,   COIN_3_0 = 0x8000, INVENTOR_6_0 = 0x10000, COIN_4_0 = 0x20000 }
Protected Types inherited from SoBase
enum	BaseFlags { IS_ENGINE = 0x01, IS_GROUP = 0x02 }
Protected Attributes inherited from SoGroup
SoChildList *	children
Protected Attributes inherited from SoNode
uint32_t	uniqueId
Protected Attributes inherited from SoFieldContainer
SbBool	isBuiltIn
Static Protected Attributes inherited from SoNode
static uint32_t	nextUniqueId = 1
static int	nextActionMethodIndex = 0

Detailed Description

The SoLOD class is used to choose a child based distance between viewer and object.

The class documentation for the SoLOD node class would be similar enough to that of SoLevelOfDetail that we will refer you to look at that one first. It will explain the general principles of what a level-of-detail mechanism is, and why and how to use it.

(The main difference between SoLOD and SoLevelOfDetail is that SoLOD uses the speedier "distance-to-viewer" technique for implementing level-of-detail functionality, versus the more correct (but potentially slower) "projected-bbox-area" technique used by SoLevelOfDetail.)

Here's a mockup example (in Inventor file format style, but easily converted to code) that shows how to use this node:

LOD {
   range [ 10, 20, 30, 40 ]

   Sphere { }
   Cylinder { }
   Cone { }
   Cube { }
   Info { }
}

For the sub-scenegraph above, when the LOD-object is less than 10 units away from the viewpoint camera, an SoSphere will be shown. For distances 10 - 20 units away, this will be changed to the SoCylinder, and so on. For distances of more than 40 units from the camera, an SoInfo node will be traversed / rendered – ie, nothing will be shown. (This is a common "trick" used to optimize rendering when models get far enough away from the camera that we want to remove them completely).

Note that when using an SoOrthographicCamera in the examiner viewers of the SoQt, SoWin and SoXt libraries, it will seem like the SoLOD node is not working when using the "Zoom" functionality. What happens is that an SoOrthographicCamera is not actually moved, the "zoom" effect is accomplished simply by changing its height-of-view setting (i.e. the value of the SoOrthographicCamera::height field), but its position remains constant. So the distance to the camera will not change, which means SoLOD will pick the same child, no matter how much one "zooms".

(The SoLevelOfDetail node uses the screen space area of the object to decide when to switch children, so that node will still work with SoOrthographicCamera.)

FILE FORMAT/DEFAULTS:

LOD {
    center 0 0 0
    range [  ]
}

Since

Inventor 2.1

See also

SoLevelOfDetail

Constructor & Destructor Documentation

SoLOD::SoLOD

(

void

)

Default constructor.

SoLOD::SoLOD

(

int

numchildren

)

Constructor.

The argument should be the approximate number of children which is expected to be inserted below this node. The number need not be exact, as it is only used as a hint for better memory resource allocation.

SoLOD::~SoLOD ( )

protectedvirtual

Destructor.

Member Function Documentation

SoType SoLOD::getTypeId ( void  ) const

virtual

Returns the type identification of an object derived from a class inheriting SoBase. This is used for run-time type checking and "downward" casting.

Usage example:

void foo(SoNode * node)
{
  if (node->getTypeId() == SoFile::getClassTypeId()) {
    SoFile * filenode = (SoFile *)node;  // safe downward cast, knows the type
  }
}

For application programmers wanting to extend the library with new nodes, engines, nodekits, draggers or others: this method needs to be overridden in all subclasses. This is typically done as part of setting up the full type system for extension classes, which is usually accomplished by using the pre-defined macros available through for instance Inventor/nodes/SoSubNode.h (SO_NODE_INIT_CLASS and SO_NODE_CONSTRUCTOR for node classes), Inventor/engines/SoSubEngine.h (for engine classes) and so on.

For more information on writing Coin extensions, see the class documentation of the toplevel superclasses for the various class groups.

Reimplemented from SoGroup.

const SoFieldData * SoLOD::getFieldData ( void  ) const

protectedvirtual

Returns a pointer to the class-wide field data storage object for this instance. If no fields are present, returns NULL.

Reimplemented from SoGroup.

void SoLOD::doAction ( SoAction *  action )

virtual

This function performs the typical operation of a node for any action.

Reimplemented from SoGroup.

void SoLOD::callback ( SoCallbackAction *  action )

virtual

Action method for SoCallbackAction.

Simply updates the state according to how the node behaves for the render action, so the application programmer can use the SoCallbackAction for extracting information about the scene graph.

Reimplemented from SoGroup.

void SoLOD::GLRender ( SoGLRenderAction *  action )

virtual

Action method for the SoGLRenderAction.

This is called during rendering traversals. Nodes influencing the rendering state in any way or who wants to throw geometry primitives at OpenGL overrides this method.

Reimplemented from SoGroup.

void SoLOD::GLRenderBelowPath ( SoGLRenderAction *  action )

virtual

Implements the SoAction::BELOW_PATH traversal method for the rendering action.

Reimplemented from SoNode.

void SoLOD::GLRenderInPath ( SoGLRenderAction *  action )

virtual

Implements the SoAction::IN_PATH traversal method for the rendering action.

Reimplemented from SoNode.

void SoLOD::GLRenderOffPath ( SoGLRenderAction *  action )

virtual

Implements the SoAction::OFF_PATH traversal method for the rendering action.

Reimplemented from SoNode.

void SoLOD::rayPick ( SoRayPickAction *  action )

virtual

Action method for SoRayPickAction.

Checks the ray specification of the action and tests for intersection with the data of the node.

Nodes influencing relevant state variables for how picking is done also overrides this method.

Reimplemented from SoNode.

void SoLOD::getBoundingBox ( SoGetBoundingBoxAction *  action )

virtual

Action method for the SoGetBoundingBoxAction.

Calculates bounding box and center coordinates for node and modifies the values of the action to encompass the bounding box for this node and to shift the center point for the scene more towards the one for this node.

Nodes influencing how geometry nodes calculates their bounding box also overrides this method to change the relevant state variables.

Reimplemented from SoGroup.

void SoLOD::getPrimitiveCount ( SoGetPrimitiveCountAction *  action )

virtual

Action method for the SoGetPrimitiveCountAction.

Calculates the number of triangle, line segment and point primitives for the node and adds these to the counters of the action.

Nodes influencing how geometry nodes calculates their primitive count also overrides this method to change the relevant state variables.

Reimplemented from SoGroup.

void SoLOD::audioRender ( SoAudioRenderAction *  action )

virtual

Action method for SoAudioRenderAction.

Does common processing for SoAudioRenderAction action instances.

Reimplemented from SoGroup.

void SoLOD::notify ( SoNotList *  l )

virtual

Notifies all auditors for this instance when changes are made.

Reimplemented from SoNode.

int SoLOD::whichToTraverse ( SoAction *  action )

protectedvirtual

Returns the child to traverse based on the ranges in SoLOD::range. Will clamp to index to the number of children. This method will return -1 if no child should be traversed. This will only happen if the node has no children though.

Member Data Documentation

SoMFFloat SoLOD::range

The distance ranges which decides when to use each child for traversal / rendering. See usage example in main class documentation of SoLOD for an explanation of how this vector should be set up correctly.

By default this vector just contains a single value 0.0f.

SoSFVec3f SoLOD::center

This vector represents an offset within the object from the geometric center point to the center point the application programmer would actually like the distance between the viewer and the object to be calculated from.

Default value is [0, 0, 0]. It is usually not necessary to change this field.

---

The documentation for this class was generated from the following files:

• SoLOD.h
• SoLOD.cpp