SoMultiDataSeparator Class Reference

Separator for combining multiple data sets More...

#include <LDM/nodes/SoMultiDataSeparator.h>

Inheritance diagram for SoMultiDataSeparator:

Public Member Functions
virtual SoType	getTypeId () const
	Returns the type identifier for this specific instance.
	SoMultiDataSeparator ()
	Constructor.
Public Member Functions inherited from SoSeparator
	SoSeparator ()
	Creates a separator node with default settings.
	SoSeparator (int nChildren)
	Constructor that takes approximate number of children.
Public Member Functions inherited from SoGroup
	SoGroup ()
	Creates an empty group node.
	SoGroup (int nChildren)
	Constructor that takes approximate number of children.
virtual void	addChild (SoNode *child)
	Adds a child as last one in group.
virtual void	insertChild (SoNode *child, int newChildIndex)
	Adds a child so that it becomes the one with the given index.
virtual SoNode *	getChild (int index) const
	Returns pointer the child node with the given index.
virtual int	findChild (const SoNode *child) const
	Finds index of given child within group.
virtual int	getNumChildren () const
	Returns number of children.
virtual void	removeChild (int index)
	Removes child with given index from group.
virtual void	removeChild (SoNode *child)
	Removes first instance of given child from group.
virtual void	removeAllChildren ()
	Removes all children from group.
virtual void	replaceChild (int index, SoNode *newChild)
	Replaces child with given index with new child.
virtual void	replaceChild (SoNode *oldChild, SoNode *newChild)
	Replaces first instance of given child with new child.
Public Member Functions inherited from SoNode
virtual void	setOverride (const SbBool state)
	Turns the override flag on or off.
virtual SbBool	isOverride () const
	Returns the state of the override flag.
virtual SoNode *	copy (SbBool copyConnections=FALSE) const
	Creates and returns an exact copy of the node.
virtual void	touch ()
	Marks an instance as modified, simulating a change to it.
Public Member Functions inherited from SoFieldContainer
void	setToDefaults ()
	Sets all fields in this object to their default values.
SbBool	hasDefaultValues () const
	Returns TRUE if all of the object's fields have their default values.
SbBool	fieldsAreEqual (const SoFieldContainer *fc) const
	Returns TRUE if this object's fields are exactly equal to fc's fields.
void	copyFieldValues (const SoFieldContainer *fc, SbBool copyConnections=FALSE)
	Copies the contents of fc's fields into this object's fields.
SoNONUNICODE SbBool	set (const char *fieldDataString)
	Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.
SbBool	set (const SbString &fieldDataString)
	Sets one or more fields in this object to the values specified in the given string, which should be a string in the Open Inventor file format.
void	get (SbString &fieldDataString)
	Returns the values of the fields of this object in the Open Inventor ASCII file format in the given string.
virtual int	getFields (SoFieldList &list) const
	Appends references to all of this object's fields to resultList, and returns the number of fields appended.
virtual int	getAllFields (SoFieldList &list) const
	Returns a list of fields, including the eventIn's and eventOut's.
virtual SoField *	getField (const SbName &fieldName) const
	Returns a the field of this object whose name is fieldName.
virtual SoField *	getEventIn (const SbName &fieldName) const
	Returns a the eventIn with the given name.
virtual SoField *	getEventOut (const SbName &fieldName) const
	Returns the eventOut with the given name.
SbBool	getFieldName (const SoField *field, SbName &fieldName) const
	Returns the name of the given field in the fieldName argument.
SbBool	enableNotify (SbBool flag)
	Notification at this Field Container is enabled (if flag == TRUE) or disabled (if flag == FALSE).
SbBool	isNotifyEnabled () const
	Notification is the process of telling interested objects that this object has changed.
virtual void	setUserData (void *data)
	Sets application data.
void *	getUserData (void) const
	Gets user application data.
Public Member Functions inherited from SoBase
virtual SbName	getName () const
	Returns the name of an instance.
virtual void	setName (const SbName &name)
	Sets the name of an instance.
void	setSynchronizable (const bool b)
	Sets this to be a ScaleViz synchronizable object.
bool	isSynchronizable () const
	Gets the ScaleViz synchronizable state of this object.
Public Member Functions inherited from SoRefCounter
void	ref () const
	Adds a reference to an instance.
void	unref () const
	Removes a reference from an instance.
void	unrefNoDelete () const
	unrefNoDelete() should be called when it is desired to decrement the reference count, but not delete the instance if this brings the reference count to zero.
int	getRefCount () const
	Returns current reference count.
void	lock () const
	lock this instance.
void	unlock () const
	unlock this instance.
Public Member Functions inherited from SoTypedObject
SbBool	isOfType (const SoType &type) const
	Returns TRUE if this object is of the type specified in type or is derived from that type.
template<typename TypedObjectClass >
SbBool	isOfType () const
	Returns TRUE if this object is of the type of class TypedObjectClass or is derived from that class.

Static Public Member Functions
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
Static Public Member Functions inherited from SoSeparator
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
Static Public Member Functions inherited from SoGroup
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
Static Public Member Functions inherited from SoNode
static SoType	getClassTypeId ()
	Returns the type identifier for this class.
static SoNode *	getByName (const SbName &name)
	A node's name can be set using SoBase::setName().
static int	getByName (const SbName &name, SoNodeList &list)
	A node's name can be set using SoBase::setName().
Static Public Member Functions inherited from SoFieldContainer
static SoType	getClassTypeId ()
	Returns the type of this class.
Static Public Member Functions inherited from SoBase
static SoType	getClassTypeId ()
	Returns type identifier for this class.
Static Public Member Functions inherited from SoTypedObject
static SoType	getClassTypeId ()
	Returns the type identifier for this class.

Additional Inherited Members
Public Types inherited from SoSeparator
enum	CacheEnabled {   OFF ,   ON ,   AUTO }
	Possible values for caching. More...
enum	FastEditing {   DISABLE = 0x01 ,   KEEP_ZBUFFER = 0x02 ,   CLEAR_ZBUFFER = 0x03 }
	Fast editing policy enumeration values. More...
Public Attributes inherited from SoSeparator
SoSFEnum	boundingBoxCaching
	Whether to cache during bounding box traversal.
SoSFEnum	renderCulling
	Whether to cull during rendering traversal.
SoSFEnum	pickCulling
	Whether to cull during picking traversal.
SoSFEnum	fastEditing
	Specifies the fast edit mode of the separator node.
SoSFInt32	renderUnitId
	Used during the ScaleViz depth compositing process, this field specifies which render unit (OIRU) will render the sub scene graph below this separator.
SoDEPRECATED SoSFEnum	renderCaching
	Whether to cache during rendering traversal.
Public Attributes inherited from SoGroup
SoSFBool	boundingBoxIgnoring
	Whether to ignore this node during bounding box traversal.

Detailed Description

Separator for combining multiple data sets

The SoMultiDataSeparator node allows you to combine multiple data sets.

This is the correct method for combining multiple data sets. Combining multiple data sets without inserting them under an SoMultiDataSeparator node may produce incorrect results and should be avoided.

Each data set is represented by an SoDataSet node (typically an SoVolumeData node).
Combining is enabled by an SoDataCompositor node for CPU combining or an SoVolumeShader node for GPU combining. A common use of GPU combining is to implement co-blending of multiple volumes, in other words using a fragment shader to combine the color and/or intensity values of the voxels.

Some rules must be followed when doing render or data compositing:

• Each SoVolumeData node must have a unique SoDataSet::dataSetId.
  
• All the SoVolumeData nodes to be composited, as well as the compositing node (e.g. SoVolumeShader for slices or SoVolumeRenderingQuality for volumes) and the rendering node (e.g. SoVolumeRender), must be under an SoMultiDataSeparator node.
• The SoVolumeData nodes to be composited must be all scalar data sets or all RGBA data sets. To composite scalar and RGBA data sets under the same SoMultiDataSeparator, set the usePalettedTexture field to false in the scalar dataset's SoVolumeData node to force the scalar data to be converted into RGBA data.
• An SoVolumeData node used in a data compositing scheme must not be inserted multiple times in the scene graph. Use another volume data node pointing to the same file.
• Each SoVolumeData node has its own resource settings (see field SoDataSet::ldmResourceParameters). The resources required for the composition are the sum of the resources for all of the SoVolumeData nodes involved.
  *
• All transfer functions must have the same 'colorMapType' and must have the same number of entries in the colormap.

GPU combining must be implemented in a shader program written in the standard GLSL language. The shader program will be specified using an SoVolumeShader node. The shader source code is loaded using (for example) an SoFragmentShader object. Uniform parameters for the shader may be specified using the subclasses of SoShaderParameter. See SoVolumeShader for more information about the shader function library provided by VolumeViz.

It is possible to compose datasets that have different dimensions, tile sizes and transformations.
In order to help fetch the correct data values in custom shaders, texture coordinates conversion functions are provided in the VolumeViz/vvizStructure.h shader include.
See SoVolumeShader for more details.

For each data set there will typically be an SoDataRange node and an SoTransferFunction node to define the mapping from data values to color values. For each SoVolumeData a separate 3D texture will be generated and sent to the GPU. 3D textures can be generated with different precision (8-bit or 12-bit) according to the SoDataSet::texturePrecision field. The texture unit used for each data set is determined by the SoDataSet::dataSetId field. All colormaps are aggregated into a single 2D texture.

A custom fragment shader can retrieve the voxel's data value from each 3D texture using the GLSL VolumeViz function:

VVIZ_DATATYPE value = VVizGetData( dataSetId, texCoord );

A custom fragment shader can lookup the color/intensity for each data value from the appropriate colormap, using the GLSL VolumeViz function:

vec4 color = VVizTransferFunction( value, colorMapId );

A custom fragment shader can then compute (using custom blending functions) the actual color for the voxel and output that color using the GLSL VolumeViz function:

VVizOutputColor( color ):

EXAMPLE

The following code shows how to do multidata rendering using an SoVolumeShader node to combine values for an SoVolumeRender node. Given two SoVolumeData nodes ds1 and ds2:

SoVolumeShader* volumeShader = new SoVolumeShader();
 
SoVolumeData* volumeData1 = new SoVolumeData();
volumeData1->dataSetId  = 0;
SoDataRange* dataRange1 = new SoDataRange();
dataRange1->dataRangeId = 0;
SoTransferFunction* colorMap1 = new SoTransferFunction();
 
SoVolumeData* volumeData2 = new SoVolumeData();
volumeData2->dataSetId  = 1;
SoDataRange* dataRange2 = new SoDataRange();
dataRange2->dataRangeId = 1;
SoTransferFunction* colorMap2 = new SoTransferFunction();
 
SoVolumeRender* volumeRender = new SoVolumeRender();
 
SoMultiDataSeparator* multiDataSep = new SoMultiDataSeparator();
  multiDataSep->addChild( volumeShader ); // Shader to combine volumes
 
  multiDataSep->addChild( volumeData1 );
  multiDataSep->addChild( dataRange1 );
  multiDataSep->addChild( colorMap1 );
 
  multiDataSep->addChild( volumeData2 );
  multiDataSep->addChild( dataRange2 );
  multiDataSep->addChild( colorMap2 );
 
  multiDataSep->addChild( volumeRender );
root->addChild( multiDataSep );

SEE ALSO

SoDataSet, SoVolumeData, SoDataCompositor, SoVolumeShader

Definition at line 227 of file SoMultiDataSeparator.h.

Constructor & Destructor Documentation

SoMultiDataSeparator()

SoMultiDataSeparator::SoMultiDataSeparator

(

)

Constructor.

Member Function Documentation

getClassTypeId()

static SoType SoMultiDataSeparator::getClassTypeId ( )

static

Returns the type identifier for this class.

getTypeId()

virtual SoType SoMultiDataSeparator::getTypeId ( ) const

virtual

Returns the type identifier for this specific instance.

Reimplemented from SoSeparator.

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

• LDM/nodes/SoMultiDataSeparator.h