vtkOpenGLInstanceCulling Class Reference

Frustum culling and LOD management. More...

#include <vtkOpenGLInstanceCulling.h>

Inheritance diagram for vtkOpenGLInstanceCulling:

Collaboration diagram for vtkOpenGLInstanceCulling:

Classes
struct	InstanceLOD

Public Types
typedef vtkObject	Superclass

Public Member Functions
virtual vtkTypeBool	IsA (const char *type)
	Return 1 if this class is the same type of (or a subclass of) the named class.
vtkOpenGLInstanceCulling *	NewInstance () const
void	PrintSelf (ostream &os, vtkIndent indent) override
	Methods invoked by print to print information about the object including superclasses.
void	InitLOD (vtkPolyData *pd)
	Initialize LOD with a polydata.
void	AddLOD (float distance, float targetReduction)
	Add a level of detail.
void	BuildCullingShaders (vtkOpenGLShaderCache *cache, vtkIdType numInstances, bool withNormals)
	Build culling shader program (if not created yet) and binds it.
vtkOpenGLHelper &	GetHelper ()
	Get helper structure.
InstanceLOD &	GetLOD (vtkIdType index)
	Get LOD structure.
vtkIdType	GetNumberOfLOD ()
	Get number of LOD currently declared.
vtkOpenGLBufferObject *	GetLODBuffer (vtkIdType index)
	Get the transform feedback buffer generated by the culling program.
void	RunCullingShaders (vtkIdType numInstances, vtkOpenGLBufferObject *matrixBuffer, vtkOpenGLBufferObject *colorBuffer, vtkOpenGLBufferObject *normalBuffer)
	Run the culling program and generate LOD buffers.
virtual void	SetColorLOD (bool)
	Overload color with unique color per LOD.
virtual bool	GetColorLOD ()
	Overload color with unique color per LOD.
Public Member Functions inherited from vtkObject
	vtkBaseTypeMacro (vtkObject, vtkObjectBase)
virtual void	DebugOn ()
	Turn debugging output on.
virtual void	DebugOff ()
	Turn debugging output off.
bool	GetDebug ()
	Get the value of the debug flag.
void	SetDebug (bool debugFlag)
	Set the value of the debug flag.
virtual void	Modified ()
	Update the modification time for this object.
virtual vtkMTimeType	GetMTime ()
	Return this object's modified time.
void	PrintSelf (ostream &os, vtkIndent indent) override
	Methods invoked by print to print information about the object including superclasses.
void	RemoveObserver (unsigned long tag)
void	RemoveObservers (unsigned long event)
void	RemoveObservers (const char *event)
void	RemoveAllObservers ()
vtkTypeBool	HasObserver (unsigned long event)
vtkTypeBool	HasObserver (const char *event)
int	InvokeEvent (unsigned long event)
int	InvokeEvent (const char *event)
unsigned long	AddObserver (unsigned long event, vtkCommand *, float priority=0.0f)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
unsigned long	AddObserver (const char *event, vtkCommand *, float priority=0.0f)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
vtkCommand *	GetCommand (unsigned long tag)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
void	RemoveObserver (vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
void	RemoveObservers (unsigned long event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
void	RemoveObservers (const char *event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
vtkTypeBool	HasObserver (unsigned long event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
vtkTypeBool	HasObserver (const char *event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object.
template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, void(T::*callback)(), float priority=0.0f)
	Overloads to AddObserver that allow developers to add class member functions as callbacks for events.
template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, void(T::*callback)(vtkObject *, unsigned long, void *), float priority=0.0f)
	Overloads to AddObserver that allow developers to add class member functions as callbacks for events.
template<class U , class T >
unsigned long	AddObserver (unsigned long event, U observer, bool(T::*callback)(vtkObject *, unsigned long, void *), float priority=0.0f)
	Allow user to set the AbortFlagOn() with the return value of the callback method.
int	InvokeEvent (unsigned long event, void *callData)
	This method invokes an event and return whether the event was aborted or not.
int	InvokeEvent (const char *event, void *callData)
	This method invokes an event and return whether the event was aborted or not.
Public Member Functions inherited from vtkObjectBase
const char *	GetClassName () const
	Return the class name as a string.
virtual vtkTypeBool	IsA (const char *name)
	Return 1 if this class is the same type of (or a subclass of) the named class.
virtual vtkIdType	GetNumberOfGenerationsFromBase (const char *name)
	Given the name of a base class of this class type, return the distance of inheritance between this class type and the named class (how many generations of inheritance are there between this class and the named class).
virtual void	Delete ()
	Delete a VTK object.
virtual void	FastDelete ()
	Delete a reference to this object.
void	InitializeObjectBase ()
void	Print (ostream &os)
	Print an object to an ostream.
virtual void	Register (vtkObjectBase *o)
	Increase the reference count (mark as used by another object).
virtual void	UnRegister (vtkObjectBase *o)
	Decrease the reference count (release by another object).
int	GetReferenceCount ()
	Return the current reference count of this object.
void	SetReferenceCount (int)
	Sets the reference count.
bool	GetIsInMemkind () const
	A local state flag that remembers whether this object lives in the normal or extended memory space.
virtual void	PrintHeader (ostream &os, vtkIndent indent)
	Methods invoked by print to print information about the object including superclasses.
virtual void	PrintTrailer (ostream &os, vtkIndent indent)
	Methods invoked by print to print information about the object including superclasses.

Static Public Member Functions
static vtkOpenGLInstanceCulling *	New ()
static vtkTypeBool	IsTypeOf (const char *type)
static vtkOpenGLInstanceCulling *	SafeDownCast (vtkObjectBase *o)
Static Public Member Functions inherited from vtkObject
static vtkObject *	New ()
	Create an object with Debug turned off, modified time initialized to zero, and reference counting on.
static void	BreakOnError ()
	This method is called when vtkErrorMacro executes.
static void	SetGlobalWarningDisplay (int val)
	This is a global flag that controls whether any debug, warning or error messages are displayed.
static void	GlobalWarningDisplayOn ()
	This is a global flag that controls whether any debug, warning or error messages are displayed.
static void	GlobalWarningDisplayOff ()
	This is a global flag that controls whether any debug, warning or error messages are displayed.
static int	GetGlobalWarningDisplay ()
	This is a global flag that controls whether any debug, warning or error messages are displayed.
Static Public Member Functions inherited from vtkObjectBase
static vtkTypeBool	IsTypeOf (const char *name)
	Return 1 if this class type is the same type of (or a subclass of) the named class.
static vtkIdType	GetNumberOfGenerationsFromBaseType (const char *name)
	Given a the name of a base class of this class type, return the distance of inheritance between this class type and the named class (how many generations of inheritance are there between this class and the named class).
static vtkObjectBase *	New ()
	Create an object with Debug turned off, modified time initialized to zero, and reference counting on.
static void	SetMemkindDirectory (const char *directoryname)
	The name of a directory, ideally mounted -o dax, to memory map an extended memory space within.
static bool	GetUsingMemkind ()
	A global state flag that controls whether vtkObjects are constructed in the usual way (the default) or within the extended memory space.

Protected Member Functions
virtual vtkObjectBase *	NewInstanceInternal () const
	vtkOpenGLInstanceCulling ()=default
	~vtkOpenGLInstanceCulling () override
void	DeleteLODs ()
void	UploadCurrentState (InstanceLOD &lod, vtkPolyData *pd)
Protected Member Functions inherited from vtkObject
	vtkObject ()
	~vtkObject () override
void	RegisterInternal (vtkObjectBase *, vtkTypeBool check) override
void	UnRegisterInternal (vtkObjectBase *, vtkTypeBool check) override
void	InternalGrabFocus (vtkCommand *mouseEvents, vtkCommand *keypressEvents=nullptr)
	These methods allow a command to exclusively grab all events.
void	InternalReleaseFocus ()
	These methods allow a command to exclusively grab all events.
Protected Member Functions inherited from vtkObjectBase
	vtkObjectBase ()
virtual	~vtkObjectBase ()
virtual void	RegisterInternal (vtkObjectBase *, vtkTypeBool check)
virtual void	UnRegisterInternal (vtkObjectBase *, vtkTypeBool check)
virtual void	ReportReferences (vtkGarbageCollector *)
	vtkObjectBase (const vtkObjectBase &)
void	operator= (const vtkObjectBase &)

Additional Inherited Members
Static Protected Member Functions inherited from vtkObjectBase
static vtkMallocingFunction	GetCurrentMallocFunction ()
static vtkReallocingFunction	GetCurrentReallocFunction ()
static vtkFreeingFunction	GetCurrentFreeFunction ()
static vtkFreeingFunction	GetAlternateFreeFunction ()
Protected Attributes inherited from vtkObject
bool	Debug
vtkTimeStamp	MTime
vtkSubjectHelper *	SubjectHelper
Protected Attributes inherited from vtkObjectBase
std::atomic< int32_t >	ReferenceCount
vtkWeakPointerBase **	WeakPointers

Detailed Description

Frustum culling and LOD management.

This class is used to cull instances based on their transformation matrix. It was designed to improve performances when there is large number of instances in vtkOpenGLGlyph3DMapper.

Each instance is tested on the GPU through vertex shader to know if it is inside of the frustum view. If it is, the distance to the camera is computed to select and send to the geometry shader the corresponding LOD index. The geometry shader register the instance to the corresponding vertex stream and therefore the corresponding transform feedback buffer in video memory.

Warning

GL_ARB_gpu_shader5 extension is required.

vtkNew<vtkOpenGLInstanceCulling> culling;
vtkIdType nbInstances = 1000000;
 
// buffer of size 16*nbInstances containing transform matrices.
vtkOpenGLBufferObject* bufferMatrix = ...;
 
// buffer of size 4*nbInstances containing color buffer to pass through.
vtkOpenGLBufferObject* bufferColor = ...;
 
// Initialize LODs
culling->InitLOD(polydata); // LOD0 : full geometry
culling->AddLOD(2.0, 0.5); // LOD1 : after 2.0, 50% triangles
culling->AddLOD(5.0, 0.99); // LOD2 : after 5.0, 1% triangles
 
// Build shader and binds
culling->BuildCullingShaders(ren, actor, nbInstances);
culling->RunCullingShaders(nbInstances, bufferMatrix, bufferColor);
 
// Get number of instances in LOD 0
int nbInstInLOD0 = culling->GetLOD(0).NumberOfInstances;
 
// Get VBO and IBO of LOD 1
vtkOpenGLBufferObject* VBO1 = culling->GetLOD(1).PositionVBO;
vtkOpenGLBufferObject* IBO1 = culling->GetLOD(1).IBO;
 
// Get instances buffer of LOD 2
// buffer is interleaved [ transformMatrix0 color0 transformMatrix1 color1 ... ]
vtkOpenGLBufferObject* buffer2 = culling->GetLODBuffer(2);

Definition at line 81 of file vtkOpenGLInstanceCulling.h.

Member Typedef Documentation

Superclass

typedef vtkObject vtkOpenGLInstanceCulling::Superclass

Definition at line 85 of file vtkOpenGLInstanceCulling.h.

Constructor & Destructor Documentation

vtkOpenGLInstanceCulling()

vtkOpenGLInstanceCulling::vtkOpenGLInstanceCulling ( )

protecteddefault

~vtkOpenGLInstanceCulling()

vtkOpenGLInstanceCulling::~vtkOpenGLInstanceCulling ( )

overrideprotected

Member Function Documentation

New()

static vtkOpenGLInstanceCulling * vtkOpenGLInstanceCulling::New ( )

static

IsTypeOf()

static vtkTypeBool vtkOpenGLInstanceCulling::IsTypeOf ( const char *  type )

static

IsA()

virtual vtkTypeBool vtkOpenGLInstanceCulling::IsA ( const char *  name )

virtual

Return 1 if this class is the same type of (or a subclass of) the named class.

Returns 0 otherwise. This method works in combination with vtkTypeMacro found in vtkSetGet.h.

Reimplemented from vtkObjectBase.

SafeDownCast()

static vtkOpenGLInstanceCulling * vtkOpenGLInstanceCulling::SafeDownCast ( vtkObjectBase *  o )

static

NewInstanceInternal()

virtual vtkObjectBase * vtkOpenGLInstanceCulling::NewInstanceInternal ( ) const

protectedvirtual

NewInstance()

vtkOpenGLInstanceCulling * vtkOpenGLInstanceCulling::NewInstance

(

)

const

PrintSelf()

void vtkOpenGLInstanceCulling::PrintSelf ( ostream &  os, vtkIndent  indent  )

overridevirtual

Methods invoked by print to print information about the object including superclasses.

Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.

Reimplemented from vtkObject.

InitLOD()

void vtkOpenGLInstanceCulling::InitLOD

(

vtkPolyData *

pd

)

Initialize LOD with a polydata.

AddLOD()

void vtkOpenGLInstanceCulling::AddLOD	(	float	distance,
		float	targetReduction
	)

Add a level of detail.

distance is the distance after which LOD is enabled targetReduction is the reduction factor applied on polydata (vtkDecimatePro is used)

See also

vtkDecimatePro::SetTargetReduction

BuildCullingShaders()

void vtkOpenGLInstanceCulling::BuildCullingShaders	(	vtkOpenGLShaderCache *	cache,
		vtkIdType	numInstances,
		bool	withNormals
	)

Build culling shader program (if not created yet) and binds it.

GetHelper()

vtkOpenGLHelper & vtkOpenGLInstanceCulling::GetHelper

(

)

Get helper structure.

GetLOD()

InstanceLOD & vtkOpenGLInstanceCulling::GetLOD

(

vtkIdType

index

)

Get LOD structure.

GetNumberOfLOD()

vtkIdType vtkOpenGLInstanceCulling::GetNumberOfLOD

(

)

Get number of LOD currently declared.

GetLODBuffer()

vtkOpenGLBufferObject * vtkOpenGLInstanceCulling::GetLODBuffer

(

vtkIdType

index

)

Get the transform feedback buffer generated by the culling program.

RunCullingShaders()

void vtkOpenGLInstanceCulling::RunCullingShaders	(	vtkIdType	numInstances,
		vtkOpenGLBufferObject *	matrixBuffer,
		vtkOpenGLBufferObject *	colorBuffer,
		vtkOpenGLBufferObject *	normalBuffer
	)

Run the culling program and generate LOD buffers.

SetColorLOD()

virtual void vtkOpenGLInstanceCulling::SetColorLOD ( bool  )

virtual

Overload color with unique color per LOD.

GetColorLOD()

virtual bool vtkOpenGLInstanceCulling::GetColorLOD ( )

virtual

Overload color with unique color per LOD.

DeleteLODs()

void vtkOpenGLInstanceCulling::DeleteLODs ( )

protected

UploadCurrentState()

void vtkOpenGLInstanceCulling::UploadCurrentState ( InstanceLOD &  lod, vtkPolyData *  pd  )

protected

---

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

• Rendering/OpenGL2/vtkOpenGLInstanceCulling.h