osg::BlendFunc Class Reference

Encapsulates OpenGL blend/transparency state. More...

Inheritance diagram for osg::BlendFunc:

List of all members.

Public Types
enum	BlendFuncMode {   DST_ALPHA = GL_DST_ALPHA, DST_COLOR = GL_DST_COLOR, ONE = GL_ONE, ONE_MINUS_DST_ALPHA = GL_ONE_MINUS_DST_ALPHA,   ONE_MINUS_DST_COLOR = GL_ONE_MINUS_DST_COLOR, ONE_MINUS_SRC_ALPHA = GL_ONE_MINUS_SRC_ALPHA, ONE_MINUS_SRC_COLOR = GL_ONE_MINUS_SRC_COLOR, SRC_ALPHA = GL_SRC_ALPHA,   SRC_ALPHA_SATURATE = GL_SRC_ALPHA_SATURATE, SRC_COLOR = GL_SRC_COLOR, CONSTANT_COLOR = GL_CONSTANT_COLOR, ONE_MINUS_CONSTANT_COLOR = GL_ONE_MINUS_CONSTANT_COLOR,   CONSTANT_ALPHA = GL_CONSTANT_ALPHA, ONE_MINUS_CONSTANT_ALPHA = GL_ONE_MINUS_CONSTANT_ALPHA, ZERO = GL_ZERO }
Public Member Functions
	BlendFunc ()
	BlendFunc (GLenum source, GLenum destination)
	BlendFunc (GLenum source, GLenum destination, GLenum source_alpha, GLenum destination_alpha)
	BlendFunc (const BlendFunc &trans, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
	Copy constructor using CopyOp to manage deep vs shallow copy.
	META_StateAttribute (osg, BlendFunc, BLENDFUNC)
virtual int	compare (const StateAttribute &sa) const
	Return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs.
virtual bool	getModeUsage (StateAttribute::ModeUsage &usage) const
	Return the modes associated with this StateAttribute.
void	setFunction (GLenum source, GLenum destination)
void	setFunction (GLenum source_rgb, GLenum destination_rgb, GLenum source_alpha, GLenum destination_alpha)
void	setSource (GLenum source)
GLenum	getSource () const
void	setSourceRGB (GLenum source)
GLenum	getSourceRGB () const
void	setSourceAlpha (GLenum source)
GLenum	getSourceAlpha () const
void	setDestination (GLenum destination)
GLenum	getDestination () const
void	setDestinationRGB (GLenum destination)
GLenum	getDestinationRGB () const
void	setDestinationAlpha (GLenum destination)
GLenum	getDestinationAlpha () const
virtual void	apply (State &state) const
	apply the OpenGL state attributes.
Protected Member Functions
virtual	~BlendFunc ()
Protected Attributes
GLenum	_source_factor
GLenum	_destination_factor
GLenum	_source_factor_alpha
GLenum	_destination_factor_alpha

---

Detailed Description

Encapsulates OpenGL blend/transparency state.

Blending combines incoming fragment with a fragment already present in the target buffer.

OpenGL 1.1 supports following source and destination blending factors: GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_DST_ALPHA, GL_ONE_MINUS_DST_ALPHA, GL_ZERO, GL_ONE.

Moreover, there are three source-only blending factors: GL_DST_COLOR, GL_ONE_MINUS_DST_COLOR, GL_SRC_ALPHA_SATURATE and two destination-only blending factors: GL_SRC_COLOR, GL_ONE_MINUS_SRC_COLOR. OpenGL 1.4 allowed to use these five blending factors as both - source and destination blending factors.

Following four source and destination blending factors were added by Imaging subset of OpenGL 1.2 and made mandatory by OpenGL 1.4: GL_CONSTANT_COLOR, GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_ALPHA, GL_ONE_MINUS_CONSTANT_ALPHA

OpenGL 1.4 further provides glBlendFuncSeparate (promoted from GL_EXT_blend_func_separate). It makes possible to set blending functions for RGB and Alpha separately. Before, it was possible to set just one blending function for RGBA.

---

Member Enumeration Documentation

enum osg::BlendFunc::BlendFuncMode

Enumerator:

DST_ALPHA
DST_COLOR
ONE
ONE_MINUS_DST_ALPHA
ONE_MINUS_DST_COLOR
ONE_MINUS_SRC_ALPHA
ONE_MINUS_SRC_COLOR
SRC_ALPHA
SRC_ALPHA_SATURATE
SRC_COLOR
CONSTANT_COLOR
ONE_MINUS_CONSTANT_COLOR
CONSTANT_ALPHA
ONE_MINUS_CONSTANT_ALPHA
ZERO

---

Constructor & Destructor Documentation

osg::BlendFunc::BlendFunc

(

)

osg::BlendFunc::BlendFunc	(	GLenum	source,
		GLenum	destination
	)

osg::BlendFunc::BlendFunc	(	GLenum	source,
		GLenum	destination,
		GLenum	source_alpha,
		GLenum	destination_alpha
	)

osg::BlendFunc::BlendFunc	(	const BlendFunc &	trans,
		const CopyOp &	copyop = CopyOp::SHALLOW_COPY
	)		[inline]

Copy constructor using CopyOp to manage deep vs shallow copy.

virtual osg::BlendFunc::~BlendFunc

(

)

[protected, virtual]

---

Member Function Documentation

virtual void osg::BlendFunc::apply

(

State &

)

const [virtual]

apply the OpenGL state attributes.

The render info for the current OpenGL context is passed in to allow the StateAttribute to obtain details on the the current context and state.

Reimplemented from osg::StateAttribute.

Reimplemented in osg::BlendFunci.

virtual int osg::BlendFunc::compare

(

const StateAttribute &

sa

)

const [inline, virtual]

Return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs.

Implements osg::StateAttribute.

Reimplemented in osg::BlendFunci.

References COMPARE_StateAttribute_Parameter, and COMPARE_StateAttribute_Types.

Referenced by osg::BlendFunci::compare().

GLenum osg::BlendFunc::getDestination

(

)

const [inline]

GLenum osg::BlendFunc::getDestinationAlpha

(

)

const [inline]

GLenum osg::BlendFunc::getDestinationRGB

(

)

const [inline]

virtual bool osg::BlendFunc::getModeUsage

(

StateAttribute::ModeUsage &

)

const [inline, virtual]

Return the modes associated with this StateAttribute.

Reimplemented from osg::StateAttribute.

References osg::StateAttribute::ModeUsage::usesMode().

GLenum osg::BlendFunc::getSource

(

)

const [inline]

GLenum osg::BlendFunc::getSourceAlpha

(

)

const [inline]

GLenum osg::BlendFunc::getSourceRGB

(

)

const [inline]

osg::BlendFunc::META_StateAttribute	(	osg	,
		BlendFunc	,
		BLENDFUNC
	)

void osg::BlendFunc::setDestination

(

GLenum

destination

)

[inline]

void osg::BlendFunc::setDestinationAlpha

(

GLenum

destination

)

[inline]

void osg::BlendFunc::setDestinationRGB

(

GLenum

destination

)

[inline]

void osg::BlendFunc::setFunction	(	GLenum	source,
		GLenum	destination
	)		[inline]

void osg::BlendFunc::setFunction	(	GLenum	source_rgb,
		GLenum	destination_rgb,
		GLenum	source_alpha,
		GLenum	destination_alpha
	)		[inline]

void osg::BlendFunc::setSource

(

GLenum

source

)

[inline]

void osg::BlendFunc::setSourceAlpha

(

GLenum

source

)

[inline]

void osg::BlendFunc::setSourceRGB

(

GLenum

source

)

[inline]

---

Member Data Documentation

GLenum osg::BlendFunc::_destination_factor [protected]

GLenum osg::BlendFunc::_destination_factor_alpha [protected]

GLenum osg::BlendFunc::_source_factor [protected]

GLenum osg::BlendFunc::_source_factor_alpha [protected]

---

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

• osg/BlendFunc