Implement a post-processing edge detection with a Sobel gradient magnitude render pass. More...

#include <vtkSobelGradientMagnitudePass.h>

Inheritance diagram for vtkSobelGradientMagnitudePass:

Collaboration diagram for vtkSobelGradientMagnitudePass:

Public Types
typedef vtkImageProcessingPass	Superclass

Public Types inherited from vtkImageProcessingPass
typedef vtkOpenGLRenderPass	Superclass

Public Types inherited from vtkOpenGLRenderPass
typedef vtkRenderPass	Superclass

Public Types inherited from vtkRenderPass
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. More...

vtkSobelGradientMagnitudePass *	NewInstance () const

void	PrintSelf (ostream &os, vtkIndent indent) override
	Methods invoked by print to print information about the object including superclasses. More...

void	Render (const vtkRenderState *s) override
	Perform rendering according to a render state `s`. More...

void	ReleaseGraphicsResources (vtkWindow *w) override
	Release graphics resources and ask components to release their own resources. More...

Public Member Functions inherited from vtkImageProcessingPass
vtkImageProcessingPass *	NewInstance () const

virtual vtkRenderPass *	GetDelegatePass ()
	Delegate for rendering the image to be processed. More...

virtual void	SetDelegatePass (vtkRenderPass *delegatePass)
	Delegate for rendering the image to be processed. More...

Public Member Functions inherited from vtkOpenGLRenderPass
vtkOpenGLRenderPass *	NewInstance () const

virtual bool	PreReplaceShaderValues (std::string &vertexShader, std::string &geometryShader, std::string &fragmentShader, vtkAbstractMapper mapper, vtkProp prop)
	Use vtkShaderProgram::Substitute to replace //VTK::XXX:YYY declarations in the shader sources. More...

virtual bool	PostReplaceShaderValues (std::string &vertexShader, std::string &geometryShader, std::string &fragmentShader, vtkAbstractMapper mapper, vtkProp prop)
	Use vtkShaderProgram::Substitute to replace //VTK::XXX:YYY declarations in the shader sources. More...

virtual bool	SetShaderParameters (vtkShaderProgram program, vtkAbstractMapper mapper, vtkProp prop, vtkOpenGLVertexArrayObject VAO=nullptr)
	Update the uniforms of the shader program. More...

virtual vtkMTimeType	GetShaderStageMTime ()
	For multi-stage render passes that need to change shader code during a single pass, use this method to notify a mapper that the shader needs to be rebuilt (rather than reuse the last cached shader. More...

virtual void	SetActiveDrawBuffers (unsigned int)
	Number of active draw buffers. More...

virtual unsigned int	GetActiveDrawBuffers ()

Public Member Functions inherited from vtkRenderPass
vtkRenderPass *	NewInstance () const

virtual int	GetNumberOfRenderedProps ()
	Number of props rendered at the last Render call. More...

Public Member Functions inherited from vtkObject
	vtkBaseTypeMacro (vtkObject, vtkObjectBase)

virtual void	DebugOn ()
	Turn debugging output on. More...

virtual void	DebugOff ()
	Turn debugging output off. More...

bool	GetDebug ()
	Get the value of the debug flag. More...

void	SetDebug (bool debugFlag)
	Set the value of the debug flag. More...

virtual void	Modified ()
	Update the modification time for this object. More...

virtual vtkMTimeType	GetMTime ()
	Return this object's modified time. More...

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. More...

unsigned long	AddObserver (const char event, vtkCommand , float priority=0.0f)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...

vtkCommand *	GetCommand (unsigned long tag)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...

void	RemoveObserver (vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...

void	RemoveObservers (unsigned long event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...

void	RemoveObservers (const char event, vtkCommand )
	Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...

vtkTypeBool	HasObserver (unsigned long event, vtkCommand *)
	Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...

vtkTypeBool	HasObserver (const char event, vtkCommand )
	Allow people to add/remove/invoke observers (callbacks) to any VTK object. More...

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. More...

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. More...

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. More...

int	InvokeEvent (unsigned long event, void *callData)
	This method invokes an event and return whether the event was aborted or not. More...

int	InvokeEvent (const char event, void callData)
	This method invokes an event and return whether the event was aborted or not. More...

Public Member Functions inherited from vtkObjectBase
const char *	GetClassName () const
	Return the class name as a string. More...

virtual void	Delete ()
	Delete a VTK object. More...

virtual void	FastDelete ()
	Delete a reference to this object. More...

void	InitializeObjectBase ()

void	Print (ostream &os)
	Print an object to an ostream. More...

virtual void	Register (vtkObjectBase *o)
	Increase the reference count (mark as used by another object). More...

virtual void	UnRegister (vtkObjectBase *o)
	Decrease the reference count (release by another object). More...

int	GetReferenceCount ()
	Return the current reference count of this object. More...

void	SetReferenceCount (int)
	Sets the reference count. More...

void	PrintRevisions (ostream &)
	Legacy. More...

virtual void	PrintHeader (ostream &os, vtkIndent indent)
	Methods invoked by print to print information about the object including superclasses. More...

virtual void	PrintTrailer (ostream &os, vtkIndent indent)
	Methods invoked by print to print information about the object including superclasses. More...

Static Public Member Functions
static vtkSobelGradientMagnitudePass *	New ()

static vtkTypeBool	IsTypeOf (const char *type)

static vtkSobelGradientMagnitudePass *	SafeDownCast (vtkObjectBase *o)

Static Public Member Functions inherited from vtkImageProcessingPass
static vtkTypeBool	IsTypeOf (const char *type)

static vtkImageProcessingPass *	SafeDownCast (vtkObjectBase *o)

Static Public Member Functions inherited from vtkOpenGLRenderPass
static vtkTypeBool	IsTypeOf (const char *type)

static vtkOpenGLRenderPass *	SafeDownCast (vtkObjectBase *o)

static vtkInformationObjectBaseVectorKey *	RenderPasses ()
	Key containing information about the current pass. More...

Static Public Member Functions inherited from vtkRenderPass
static vtkTypeBool	IsTypeOf (const char *type)

static vtkRenderPass *	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. More...

static void	BreakOnError ()
	This method is called when vtkErrorMacro executes. More...

static void	SetGlobalWarningDisplay (int val)
	This is a global flag that controls whether any debug, warning or error messages are displayed. More...

static void	GlobalWarningDisplayOn ()
	This is a global flag that controls whether any debug, warning or error messages are displayed. More...

static void	GlobalWarningDisplayOff ()
	This is a global flag that controls whether any debug, warning or error messages are displayed. More...

static int	GetGlobalWarningDisplay ()
	This is a global flag that controls whether any debug, warning or error messages are displayed. More...

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. More...

static vtkObjectBase *	New ()
	Create an object with Debug turned off, modified time initialized to zero, and reference counting on. More...

Protected Member Functions
virtual vtkObjectBase *	NewInstanceInternal () const

	vtkSobelGradientMagnitudePass ()
	Default constructor. More...

	~vtkSobelGradientMagnitudePass () override
	Destructor. More...

Protected Member Functions inherited from vtkImageProcessingPass
	vtkImageProcessingPass ()
	Default constructor. More...

	~vtkImageProcessingPass () override
	Destructor. More...

void	RenderDelegate (const vtkRenderState s, int width, int height, int newWidth, int newHeight, vtkOpenGLFramebufferObject fbo, vtkTextureObject *target)
	Render delegate with a image of different dimensions than the original one. More...

Protected Member Functions inherited from vtkOpenGLRenderPass
	vtkOpenGLRenderPass ()

	~vtkOpenGLRenderPass () override

void	PreRender (const vtkRenderState *s)
	Call before rendering to update the actors' information keys. More...

void	PostRender (const vtkRenderState *s)
	Call after rendering to clean up the actors' information keys. More...

Protected Member Functions inherited from vtkRenderPass
	vtkRenderPass ()
	Default constructor. More...

	~vtkRenderPass () override
	Destructor. More...

void	UpdateCamera (vtkRenderer *renderer)
	Call UpdateCamera() on Renderer. More...

void	ClearLights (vtkRenderer *renderer)
	Call ClearLights() on Renderer. More...

void	UpdateLightGeometry (vtkRenderer *renderer)
	Call UpdateLightGeometry() on Renderer. More...

void	UpdateLights (vtkRenderer *renderer)
	Call UpdateLights() on Renderer. More...

void	UpdateGeometry (vtkRenderer *renderer)
	Call UpdateGeometry() on Renderer. More...

void	SetLastRenderingUsedDepthPeeling (vtkRenderer *renderer, bool value)
	Modify protected member LastRenderingUsedDepthPeeling on Renderer. More...

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. More...

void	InternalReleaseFocus ()
	These methods allow a command to exclusively grab all events. More...

Protected Member Functions inherited from vtkObjectBase
	vtkObjectBase ()

virtual	~vtkObjectBase ()

virtual void	CollectRevisions (ostream &)

virtual void	ReportReferences (vtkGarbageCollector *)

	vtkObjectBase (const vtkObjectBase &)

void	operator= (const vtkObjectBase &)

Protected Attributes
vtkOpenGLFramebufferObject *	FrameBufferObject
	Graphics resources. More...

vtkTextureObject *	Pass1

vtkTextureObject *	Gx1

vtkTextureObject *	Gy1

vtkOpenGLHelper *	Program1

vtkOpenGLHelper *	Program2

Protected Attributes inherited from vtkImageProcessingPass
vtkRenderPass *	DelegatePass

Protected Attributes inherited from vtkOpenGLRenderPass
unsigned int	ActiveDrawBuffers = 0

Protected Attributes inherited from vtkRenderPass
int	NumberOfRenderedProps

Protected Attributes inherited from vtkObject
bool	Debug

vtkTimeStamp	MTime

vtkSubjectHelper *	SubjectHelper

Protected Attributes inherited from vtkObjectBase
vtkAtomicInt32	ReferenceCount

vtkWeakPointerBase **	WeakPointers

Detailed Description

Implement a post-processing edge detection with a Sobel gradient magnitude render pass.

Detect the edges of the image renderered by its delegate. Edge-detection uses a Sobel high-pass filter (3x3 kernel).

This pass expects an initialized depth buffer and color buffer. Initialized buffers means they have been cleared with farest z-value and background color/gradient/transparent color. An opaque pass may have been performed right after the initialization.

The delegate is used once.

Its delegate is usually set to a vtkCameraPass or to a post-processing pass.

This pass requires a OpenGL context that supports texture objects (TO), framebuffer objects (FBO) and GLSL. If not, it will emit an error message and will render its delegate and return.

Implementation:: To compute the gradient magnitude, the x and y components of the gradient (Gx and Gy) have to be computed first. Each computation of Gx and Gy uses a separable filter. The first pass takes the image from the delegate as the single input texture. The first pass has two outputs, one for the first part of Gx, Gx1, result of a convolution with (-1 0 1), one for the first part of Gy, Gy1, result of a convolution with (1 2 1). The second pass has two inputs, Gx1 and Gy1. Kernel (1 2 1)^T is applied to Gx1 and kernel (-1 0 1)^T is applied to Gx2. It gives the values for Gx and Gy. Those values are then used to compute the magnitude of the gradient which is stored in the render target. The gradient computation happens per component (R,G,B). A is arbitrarly set to 1 (full opacity).