OpenGl_PBREnvironment Class Reference

This class contains specular and diffuse maps required for Image Base Lighting (IBL) in PBR shading model with it's generation methods. More...

#include <OpenGl_PBREnvironment.hxx>

Inheritance diagram for OpenGl_PBREnvironment:

Public Member Functions
void	Bind (const occ::handle< OpenGl_Context > &theCtx)
	Binds diffuse and specular IBL maps to the corresponding texture units.
void	Unbind (const occ::handle< OpenGl_Context > &theCtx)
	Unbinds diffuse and specular IBL maps.
void	Clear (const occ::handle< OpenGl_Context > &theCtx, const NCollection_Vec3< float > &theColor=NCollection_Vec3< float >(1.f))
	Fills all mipmaps of specular IBL map and diffuse IBL map with one color. So that environment illumination will be constant.
void	Bake (const occ::handle< OpenGl_Context > &theCtx, const occ::handle< OpenGl_Texture > &theEnvMap, bool theZIsInverted=false, bool theIsTopDown=true, size_t theDiffMapNbSamples=1024, size_t theSpecMapNbSamples=256, float theProbability=0.99f)
	Generates specular and diffuse (irradiance) IBL maps.
unsigned int	SpecMapLevelsNumber () const
	Returns number of mipmap levels used in specular IBL map. It can be different from value passed to creation method.
unsigned int	Pow2Size () const
	Returns size of IBL maps sides as power of 2. So that the real size can be calculated as 2^Pow2Size()
bool	SizesAreDifferent (unsigned int thePow2Size, unsigned int theSpecMapLevelsNumber) const
	Checks whether the given sizes affects to the current ones. It can be imagined as creation of new PBR environment. If creation method with this values returns the PBR environment having real sizes which are equals to current ones then this method will return false. It is handful when sizes are required to be changed. If this method returns false there is no reason to recreate PBR environment in order to change sizes.
bool	IsNeededToBeBound () const
	Indicates whether IBL map's textures have to be bound or it is not obligate.
void	Release (OpenGl_Context *theCtx) override
	Releases all OpenGL resources. It must be called before destruction.
size_t	EstimatedDataSize () const override
	Returns estimated GPU memory usage for holding data without considering overheads and allocation alignment rules.
bool	IsComplete () const
	Checks completeness of PBR environment. Creation method returns only completed objects or null handles otherwise.
	~OpenGl_PBREnvironment () override
	Destructor. Warning! 'Release' method must be called before destruction. Otherwise unhandled critical error will be generated.
Public Member Functions inherited from OpenGl_NamedResource
	OpenGl_NamedResource (const TCollection_AsciiString &theId)
	Empty constructor.
const TCollection_AsciiString &	ResourceId () const
	Return resource name.
Public Member Functions inherited from OpenGl_Resource
	OpenGl_Resource ()
	Empty constructor.
	~OpenGl_Resource () override
	Destructor. Inheritors should call Clean (NULL) within it.
virtual void	DumpJson (Standard_OStream &theOStream, int theDepth=-1) const
	Dumps the content of me into the stream.
Public Member Functions inherited from Standard_Transient
	Standard_Transient ()
	Empty constructor.
	Standard_Transient (const Standard_Transient &)
	Copy constructor – does nothing.
Standard_Transient &	operator= (const Standard_Transient &)
	Assignment operator, needed to avoid copying reference counter.
virtual	~Standard_Transient ()=default
	Destructor must be virtual.
virtual const opencascade::handle< Standard_Type > &	DynamicType () const
	Returns a type descriptor about this object.
bool	IsInstance (const opencascade::handle< Standard_Type > &theType) const
	Returns a true value if this is an instance of Type.
bool	IsInstance (const char *const theTypeName) const
	Returns a true value if this is an instance of TypeName.
bool	IsKind (const opencascade::handle< Standard_Type > &theType) const
	Returns true if this is an instance of Type or an instance of any class that inherits from Type. Note that multiple inheritance is not supported by OCCT RTTI mechanism.
bool	IsKind (const char *const theTypeName) const
	Returns true if this is an instance of TypeName or an instance of any class that inherits from TypeName. Note that multiple inheritance is not supported by OCCT RTTI mechanism.
Standard_Transient *	This () const
	Returns non-const pointer to this object (like const_cast). For protection against creating handle to objects allocated in stack or call from constructor, it will raise exception Standard_ProgramError if reference counter is zero.
int	GetRefCount () const noexcept
	Get the reference counter of this object.
void	IncrementRefCounter () noexcept
	Increments the reference counter of this object. Uses relaxed memory ordering since incrementing only requires atomicity, not synchronization with other memory operations.
int	DecrementRefCounter () noexcept
	Decrements the reference counter of this object; returns the decremented value. Uses release ordering for the decrement to ensure all writes to the object are visible before the count reaches zero. An acquire fence is added only when the count reaches zero, ensuring proper synchronization before deletion. This is more efficient than using acq_rel for every decrement.
virtual void	Delete () const
	Memory deallocator for transient classes.

Static Public Member Functions
static occ::handle< OpenGl_PBREnvironment >	Create (const occ::handle< OpenGl_Context > &theCtx, unsigned int thePow2Size=9, unsigned int theSpecMapLevelsNum=6, const TCollection_AsciiString &theId="PBREnvironment")
	Creates and initializes new PBR environment. It is the only way to create OpenGl_PBREnvironment.
Static Public Member Functions inherited from Standard_Transient
static constexpr const char *	get_type_name ()
	Returns a type descriptor about this object.
static const opencascade::handle< Standard_Type > &	get_type_descriptor ()
	Returns type descriptor of Standard_Transient class.

Additional Inherited Members
Public Types inherited from Standard_Transient
typedef void	base_type
	Returns a type descriptor about this object.
Protected Attributes inherited from OpenGl_NamedResource
TCollection_AsciiString	myResourceId
	resource name

Detailed Description

This class contains specular and diffuse maps required for Image Base Lighting (IBL) in PBR shading model with it's generation methods.

Constructor & Destructor Documentation

~OpenGl_PBREnvironment()

OpenGl_PBREnvironment::~OpenGl_PBREnvironment ( )

override

Destructor. Warning! 'Release' method must be called before destruction. Otherwise unhandled critical error will be generated.

Member Function Documentation

Bake()

void OpenGl_PBREnvironment::Bake	(	const occ::handle< OpenGl_Context > &	theCtx,
		const occ::handle< OpenGl_Texture > &	theEnvMap,
		bool	theZIsInverted = false,
		bool	theIsTopDown = true,
		size_t	theDiffMapNbSamples = 1024,
		size_t	theSpecMapNbSamples = 256,
		float	theProbability = 0.99f )

Generates specular and diffuse (irradiance) IBL maps.

Parameters

theCtx	OpenGL context
theEnvMap	source environment map
theZIsInverted	flags indicates whether environment cubemap has inverted Z axis or not
theIsTopDown	flags indicates whether environment cubemap has top-down memory layout or not
theDiffMapNbSamples	number of samples in Monte-Carlo integration for diffuse IBL spherical harmonics calculation
theSpecMapNbSamples	number of samples in Monte-Carlo integration for specular IBL map generation
theProbability	controls strength of samples number reducing strategy during specular IBL map baking (see 'SpecIBLMapSamplesFactor' for details) theZIsInverted and theIsTopDown can be taken from Graphic3d_CubeMap source of environment cubemap. theDiffMapNbSamples and theSpecMapNbSamples is the main parameter directly affected to performance.

Bind()

void OpenGl_PBREnvironment::Bind

(

const occ::handle< OpenGl_Context > &

theCtx

)

Binds diffuse and specular IBL maps to the corresponding texture units.

Clear()

void OpenGl_PBREnvironment::Clear	(	const occ::handle< OpenGl_Context > &	theCtx,
		const NCollection_Vec3< float > &	theColor = NCollection_Vec3< float >(1.f) )

Fills all mipmaps of specular IBL map and diffuse IBL map with one color. So that environment illumination will be constant.

Create()

static occ::handle< OpenGl_PBREnvironment > OpenGl_PBREnvironment::Create ( const occ::handle< OpenGl_Context > & theCtx, unsigned int thePow2Size = 9, unsigned int theSpecMapLevelsNum = 6, const TCollection_AsciiString & theId = "PBREnvironment" )

static

Creates and initializes new PBR environment. It is the only way to create OpenGl_PBREnvironment.

Parameters

theCtx	OpenGL context where environment will be created
thePow2Size	final size of texture's sides can be calculated as 2^thePow2Size; if thePow2Size less than 1 it will be set to 1
theSpecMapLevelsNum	number of mipmap levels used in specular IBL map; if theSpecMapLevelsNum less than 2 or less than Pow2Size + 1 it will be set to the corresponding values.
theId	OpenGl_Resource name

Returns

handle to created PBR environment or NULL handle in case of fail

EstimatedDataSize()

size_t OpenGl_PBREnvironment::EstimatedDataSize ( ) const

inlineoverridevirtual

Returns estimated GPU memory usage for holding data without considering overheads and allocation alignment rules.

Implements OpenGl_Resource.

IsComplete()

bool OpenGl_PBREnvironment::IsComplete ( ) const

inline

Checks completeness of PBR environment. Creation method returns only completed objects or null handles otherwise.

IsNeededToBeBound()

bool OpenGl_PBREnvironment::IsNeededToBeBound ( ) const

inline

Indicates whether IBL map's textures have to be bound or it is not obligate.

Pow2Size()

unsigned int OpenGl_PBREnvironment::Pow2Size ( ) const

inline

Returns size of IBL maps sides as power of 2. So that the real size can be calculated as 2^Pow2Size()

Release()

void OpenGl_PBREnvironment::Release ( OpenGl_Context * theCtx )

overridevirtual

Releases all OpenGL resources. It must be called before destruction.

Implements OpenGl_Resource.

SizesAreDifferent()

bool OpenGl_PBREnvironment::SizesAreDifferent	(	unsigned int	thePow2Size,
		unsigned int	theSpecMapLevelsNumber ) const

Checks whether the given sizes affects to the current ones. It can be imagined as creation of new PBR environment. If creation method with this values returns the PBR environment having real sizes which are equals to current ones then this method will return false. It is handful when sizes are required to be changed. If this method returns false there is no reason to recreate PBR environment in order to change sizes.

SpecMapLevelsNumber()

unsigned int OpenGl_PBREnvironment::SpecMapLevelsNumber ( ) const

inline

Returns number of mipmap levels used in specular IBL map. It can be different from value passed to creation method.

Unbind()

void OpenGl_PBREnvironment::Unbind

(

const occ::handle< OpenGl_Context > &

theCtx

)

Unbinds diffuse and specular IBL maps.

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

• OpenGl_PBREnvironment.hxx