Node to record vertex attributes from shaders into buffer objects. More...

#include <Inventor/nodes/SoVertexAttribFeedback.h>

Inheritance diagram for SoVertexAttribFeedback:

Public Types
enum	BufferMode { INTERLEAVED , SEPARATE }
	This enum is used by the field buffersMode to describe the data packing format in the buffer objects. More...

enum	PrimitiveType { LINES , POINTS , TRIANGLES }
	This enum is used to setup the expected recorded primitive type from the shaders. More...

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 Member Functions
virtual SoType	getTypeId () const
	Returns the type identifier for this specific instance.

	SoVertexAttribFeedback ()
	Default constructor.

void	registerFeedback (const SbString &varyingName, SoBufferObject *bufferObject, int primitiveSize=-1)
	This function allows to attach a buffer object to a specific varying of the shader pushed on the state.

void	unregisterFeedback (const SbString &varyingName)
	This function is used to unregister a varying registered with the registerFeedback function.

int	getGeneratedPrimitivesCount () const
	This function returns the number of generated primitives during the traversal of the sub scene graph.

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 SbBool	isSupported (SoState *state)
	This function indicates if the vertex attributes feedback feature is available on this system.

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.

Public Attributes
SoSFBool	disableFragmentProcessing
	Turn off the fragment rasterizer.

SoSFBool	autoResizeBuffers
	Set this field to TRUE when the size of the recorded varyings is not known.

SoSFBool	queryGeneratedPrimitivesCount
	Read back the number of recorded primitives.

SoSFEnum	buffersMode
	The buffer mode used to record the primitives.

SoSFEnum	primitiveType
	The type of primitive recorded during traversal.

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.

Additional Inherited Members
Related Symbols inherited from SoSeparator
#define	SO_RENDERUNITID_NONE (-1)
	Don't traverse any children.

#define	SO_RENDERUNITID_INHERIT (-2)
	Inherit value from state.

#define	SO_RENDERUNITID_ALL (-3)
	Traverse all children.

Detailed Description

Node to record vertex attributes from shaders into buffer objects.

This node is used to record selected vertex attributes for each primitive processed by the OpenGL system. The recorded vertex attributes may be stored in separate SoGpuBufferObjects or interleaved into a single buffer object.

This node can only be used when an GLSL shader is enabled on the Open Inventor state. If the active shader contains a geometry shader the attributes are recorded from the varyings declared in it, otherwise it records the attributes from the vertex shader.

The function registerFeedback is used to specify the buffer object, which will receive the data, attached to a specified varying.

The scene graph which will be rendered during the traversal (can be any shape used as input of the geometry or vertex shader) is specified using the regular addChild function from the class SoSeparator.

This node provides a mechanism for the following features:

Rasterizer can be disabled to prevent rendering the generated primitives. This is useful when the main behavior is to record computed primitives from the geometry or vertex shader.
The SoGpuBufferObject can be automatically resized to be able to record all the data.
The number of generated primitives can be retrieved after the traversal.

Limitations

The automatic resize of the buffer objects requires two traversal of the children, one to compute the number of primitives which will be generated and the actual traversal.
Most of the regular actions (except Render and Write) don't traverse the children.

FILE FORMAT/DEFAULT

disableFragmentProcessing	TRUE
autoResizeBuffers	FALSE
queryGeneratedPrimitivesCount	FALSE
buffersMode	SEPARATE
primitiveType	TRIANGLES

ACTION BEHAVIOR

SoGLRenderAction

Member Enumeration Documentation

◆ BufferMode

enum SoVertexAttribFeedback::BufferMode

This enum is used by the field buffersMode to describe the data packing format in the buffer objects.

Enumerator
INTERLEAVED	All varyings are recorded, interleaved, in a single buffer object.
SEPARATE	Each varying is recorded in a separate buffer object.

Definition at line 104 of file SoVertexAttribFeedback.h.

◆ PrimitiveType

enum SoVertexAttribFeedback::PrimitiveType

This enum is used to setup the expected recorded primitive type from the shaders.

Enumerator
LINES	The shader is supposed to generate LINES.
POINTS	The shader is supposed to generate POINTS.
TRIANGLES	The shader is supposed to generate TRIANGLES.

Definition at line 118 of file SoVertexAttribFeedback.h.

Constructor & Destructor Documentation

◆ SoVertexAttribFeedback()

SoVertexAttribFeedback::SoVertexAttribFeedback ( )

Default constructor.

Member Function Documentation

◆ getClassTypeId()

static SoType SoVertexAttribFeedback::getClassTypeId ( )

static

Returns the type identifier for this class.

◆ getGeneratedPrimitivesCount()

int SoVertexAttribFeedback::getGeneratedPrimitivesCount ( ) const

This function returns the number of generated primitives during the traversal of the sub scene graph.

NOTE: The returned value is undefined if the field queryGeneratedPrimitivesCount is not set to TRUE.

Returns: The number of generated primitives.

◆ getTypeId()

virtual SoType SoVertexAttribFeedback::getTypeId ( ) const

virtual

Returns the type identifier for this specific instance.

Reimplemented from SoSeparator.

◆ isSupported()

static SbBool SoVertexAttribFeedback::isSupported ( SoState * state )

static

This function indicates if the vertex attributes feedback feature is available on this system.

When using a debug build of Open Inventor, some "no context available" warning messages may be generated. You can ignore them or see SoGLExtension for an example of using SoGLContext to avoid them.

Returns: TRUE if vertex attributes feedback is supported.

◆ registerFeedback()

void SoVertexAttribFeedback::registerFeedback	(	const SbString &	varyingName,
		SoBufferObject *	bufferObject,
		int	primitiveSize = `-1`
	)

This function allows to attach a buffer object to a specific varying of the shader pushed on the state.

When the buffersMode field is set to INTERLEAVED only the first specified bufferObject is used.

The primitiveSize parameter is used to compute the actual size of buffer objects when autoResizeBuffers is set to TRUE, it is ignored otherwise; It must be the size of each primitive, in bytes. When the buffer mode is set to INTERLEAVED the value must be the accumulated size in bytes for all the varyings. The actual buffer size is computed by multiplying the primitiveSize by the number of primitives and by the size of the data type (float). When the value is -1 (the default value) Open Inventor uses 3 * sizeof(float) * numVerticesPerPrimtive, which is the size of a basic triangle with 3 vertices of 3 float-components, for a triangle the computed value is 3 * sizeof(float) * 3.

NOTE: When the buffer mode is set to INTERLEAVED only the first specified buffer object is used the following ones are ignored.

Parameters

varyingName	The name of the varying which must will be added to the list of recorded varyings.
bufferObject	The buffer object which will receive the recorded values from the varying.
primitiveSize	The size, in bytes, of one primitive, used when the autoResizeBuffers field is set to TRUE.

◆ unregisterFeedback()

void SoVertexAttribFeedback::unregisterFeedback ( const SbString & varyingName )

This function is used to unregister a varying registered with the registerFeedback function.

Parameters

varyingName The name of the varying to unregister, previously registered using the registerFeeback function.

Member Data Documentation

◆ autoResizeBuffers

SoSFBool SoVertexAttribFeedback::autoResizeBuffers

Set this field to TRUE when the size of the recorded varyings is not known.

It provides a mechanism to automatically resize the buffer objects.

This is implemented by performing a first traversal of the children with OpenGL queries enabled to record the number of generated primitives during this traversal. Then the value of the query is used to compute the size in bytes of the buffer object and a second traversal is performed for the actual primitives recording.

Default value is FALSE.

Definition at line 150 of file SoVertexAttribFeedback.h.

◆ buffersMode

SoSFEnum SoVertexAttribFeedback::buffersMode

The buffer mode used to record the primitives.

Use enum BufferMode. Default is SEPARATE.

Definition at line 165 of file SoVertexAttribFeedback.h.

◆ disableFragmentProcessing

SoSFBool SoVertexAttribFeedback::disableFragmentProcessing

Turn off the fragment rasterizer.

It means that the result of the shader is not rendered.

Most of the time the main goal of this node is to record the result of varyings from the geometry shaders and the recorded primitives are not supposed to be rendered.

Default value is TRUE.

Definition at line 137 of file SoVertexAttribFeedback.h.

◆ primitiveType

SoSFEnum SoVertexAttribFeedback::primitiveType

The type of primitive recorded during traversal.

Use enum PrimitiveType. Default is TRIANGLES.

Definition at line 171 of file SoVertexAttribFeedback.h.

◆ queryGeneratedPrimitivesCount

SoSFBool SoVertexAttribFeedback::queryGeneratedPrimitivesCount

Read back the number of recorded primitives.

The read back is performed only when this field is set to TRUE and the method getGeneratedPrimitivesCount returns the value.