SoOctreeOrdering Class Reference
[Groups, Large Model]

Group node derived from SoRenderList that maintains a transparent octree organization of the shapes below it. More...

#include <Inventor/nodes/SoOctreeOrdering.h>

Inheritance diagram for SoOctreeOrdering:

Public Member Functions
virtual SoType	getTypeId () const
	SoOctreeOrdering ()
	SoOctreeOrdering (int numChildren)
void	setOctreeDrawing (SbBool enable)
SbBool	isOctreeDrawing (void)
SbBool	isChainingOn (void)
void	setHandleTransparency (SbBool handle)
SbBool	getHandleTransparency ()
void	reset ()
Static Public Member Functions
static SoType	getClassTypeId ()
static void	setReportCB (SoReportCB func, void userData)
Public Attributes
SoSFBool	dropCulling
SoSFUInt32	dropScreenArea
SoSFBool	boundingBoxSubstitutes
SoSFBool	useMovingQueue
SoSFBool	adjustDecimation

Detailed Description

Group node derived from SoRenderList that maintains a transparent octree organization of the shapes below it.

This speeds view frustum culling in large scenes in which the viewer moves through the scene and much of the scene is not visible at any given time.

The SoOctreeOrdering node uses the functionality from SoRenderList to create a list of paths to the shapes beneath it. It then reorganizes the list of shapes into an octree division of space. During action traversal, it traverses the octree instead of the scene graph. This results in a front to back traversal that quickly skips sections of space that would be culled by the view frustum.

NOTE: This class does not exist in Open Inventor 10.0 and later.

The OctreeOrdering node draws a bounding box to replace cells in the octree that contain shapes but that are too small, based on an approximate screen size. If a larger shape had already been rendered that passes through this cell, the cell will be culled instead of using the bounding box so that no rendered geometry will be covered by a bounding box. This behavior can be altered by the fields listed below.

To specify the maximum depth during octree ordering, use environment variable IV_OCTREE_MAX_DEPTH. The default is 8.

To request an outline of the octree quadrants be drawn as a debugging aid to allow you to see how your scene is distributed throughout the octree, set environment variable OIV_DRAW_OCTREE to 1 or use the method setOctreeDrawing.

Note: If an SoOcclusionCulling node is inserted below the SoOctreeOrdering node, the latter can pass its view-frustum-culled renderObject list to the occlusion node, which will perform an occlusion culling test to reduce even further the number of objects to render. See the isHead field of SoRenderList for additional info.

FILE FORMAT/DEFAULT

dropCulling	TRUE
dropScreenArea	5
boundingBoxSubstitutes	TRUE
useMovingQueue	TRUE
adjustDecimation	TRUE
renderCaching	AUTO
boundingBoxCaching	AUTO
renderCulling	AUTO
pickCulling	AUTO
fastEditing	DISABLE
isHead	TRUE

ACTION BEHAVIOR

SoGLRenderAction

SoGetPrimitiveCountAction

SoSeparator

SoRenderObjectListElement

Constructor & Destructor Documentation

SoOctreeOrdering::SoOctreeOrdering ( )

Default constructor.

Note: Do not modify an instance of this node or any of its children unless this node has a ref count greater than zero. If the node is itself the child of a grouping node then the ref count is automatically greater than zero, otherwise you must explicitly increment the ref count by calling the ref() method.

SoOctreeOrdering::SoOctreeOrdering ( int numChildren )

Constructor that takes approximate number of children as a hint.

Note: Do not modify an instance of this node or any of its children unless this node has a ref count greater than zero. If the node is itself the child of a grouping node then the ref count is automatically greater than zero, otherwise you must explicitly increment the ref count by calling the ref() method.

Member Function Documentation

static SoType SoOctreeOrdering::getClassTypeId ( ) [static]

Returns the type identifier for this class.

Reimplemented from SoRenderList.

SbBool SoOctreeOrdering::getHandleTransparency ( )

virtual SoType SoOctreeOrdering::getTypeId ( ) const [virtual]

Returns the type identifier for this specific instance.

Reimplemented from SoRenderList.

SbBool SoOctreeOrdering::isChainingOn ( void ) [inline]

Returns TRUE if the octree is chained with another culling node.

SbBool SoOctreeOrdering::isOctreeDrawing ( void )

Returns TRUE if octree drawing is enabled.

void SoOctreeOrdering::reset ( )

Allows to rebuild the octree from scratch.

void SoOctreeOrdering::setHandleTransparency ( SbBool handle )

If handle transparency is turned on, the octree will handle transparency and render cache transparent objects.

Default is TRUE;

void SoOctreeOrdering::setOctreeDrawing ( SbBool enable )

Enables/disables octree drawing.

Octree drawing will draw outlines around the octree quadrants, allowing you to see how your scene is distributed throughout the octree. This can be useful for debugging purposes.

static void SoOctreeOrdering::setReportCB	(	SoReportCB *	func,
		void *	userData
	)			`[static]`

This callback can be used to get render statistics: the number of objects in the octree, and the number of objects actually rendered.

If the application is using an MP viewer, each render thread will call the callback function at the end of the octree traversal to let the application know how many objects it rendered. This is useful to see how the rendering work is distributed across the threads.

Member Data Documentation

SoSFBool SoOctreeOrdering::adjustDecimation

If TRUE, the octree will alter the decimation percentage for objects depending on how large they are in the view.

This causes objects closer to the camera to appear in more detail than objects further away.

SoSFBool SoOctreeOrdering::boundingBoxSubstitutes

Enables use of bounding boxes for cells in the octree that contain shapes, but would appear on the screen smaller than the dropScreenArea threshold.

SoSFBool SoOctreeOrdering::dropCulling

Enables culling of shapes that are too small on the screen.

SoSFUInt32 SoOctreeOrdering::dropScreenArea

Sets threshold in pixels for drop culling and bounding box substitutes.

SoSFBool SoOctreeOrdering::useMovingQueue

Sets how this node should handle moving render objects.

If TRUE, then the moving objects are kept in a separate render list, and are not sorted into the octree, meaning that they will not be drop culled. If FALSE, moving objects will be sorted into the octree after each motion, taking more time, but enabling drop and view frustum culling for the moving objects.

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

Inventor/nodes/SoOctreeOrdering.h

SoOctreeOrdering Class Reference [Groups, Large Model]

Public Member Functions

Static Public Member Functions

Public Attributes