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sglBlending Class Reference

#include <sglStatelet.hpp>

Inheritance diagram for sglBlending::

List of all members.

Public Types
enum	BlendFuncEnum {   eZERO = GL_ZERO,   eONE = GL_ONE,   eSRC_COLOR = GL_SRC_COLOR,   eONE_MINUS_SRC_COLOR = GL_ONE_MINUS_SRC_COLOR,   eDST_COLOR = GL_DST_COLOR,   eONE_MINUS_DST_COLOR = GL_ONE_MINUS_DST_COLOR,   eSRC_ALPHA = GL_SRC_ALPHA,   eONE_MINUS_SRC_ALPHA = GL_ONE_MINUS_SRC_ALPHA,   eDST_ALPHA = GL_DST_ALPHA,   eONE_MINUS_DST_ALPHA = GL_ONE_MINUS_DST_ALPHA,   eSRC_ALPHA_SATURATE = GL_SRC_ALPHA_SATURATE }
Public Methods
	sglBlending (BlendFuncEnum src_func=eSRC_ALPHA, BlendFuncEnum dst_func=eONE_MINUS_SRC_ALPHA, bool on=false)
virtual	~sglBlending ()
void	enable (bool on)
bool	isEnabled () const
void	setBlendFunc (BlendFuncEnum src_func, BlendFuncEnum dst_func)
void	getBlendFunc (BlendFuncEnum &src_func, BlendFuncEnum &dst_func) const
void	apply (sglCurrState *curr_state) const
virtual bool	getSorted () const
virtual void	printInfo (ostream &ostrm, const char *indent_string) const

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Detailed Description

This statelet controls the OpenGL blending state by issuing the glBlendFunc() function and the glEnable(GL_BLEND_FUNC). Even when this statelet is disabled by calling sglBlending::enable(false), the blend function defined here is used by the sglTransparency and most of the sglAntiAlias* statelets to perform their blending. Because of this the default blending function is SRC_ALPHA, ONE_MINUS_SRC_ALPHA. If this blending mode is not desired for some of these other statelets then an sglBlending statelet can be included which defines the desired blend function (without ever enabling it).

Example:

   sglBlending *blending = new sglBlending;  // defaults to disabled
   blending->setBlendFunc(sglBlending::eSRC_ALPHA,
                          sglBlending::eONE_MINUS_SRC_ALPHA);
   blending->enable(true);

Todo:

Add support for GL_EXT_blend_color.

Definition at line 591 of file sglStatelet.hpp.

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Member Enumeration Documentation

enum sglBlending::BlendFuncEnum

The list of possible blend functions. Definition at line 595 of file sglStatelet.hpp.

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Constructor & Destructor Documentation

sglBlending::sglBlending ( BlendFuncEnum src_func = eSRC_ALPHA, BlendFuncEnum dst_func = eONE_MINUS_SRC_ALPHA, bool on = false ) [inline]

Constructor (also default constructor). Parameters: src_func   Enum indicating how the source values are combined in the blend function (default is sglBlending::eSRC_ALPHA). dst_func   Enum indicating how the destination values are combined in the blend function (default is sglBlending::eONE_MINUS_SRC_ALPHA). on   True to enable blending otherwise false (default is false). Definition at line 618 of file sglStatelet.hpp.

sglBlending::~sglBlending ( ) [inline, virtual]

virtual destructor. Definition at line 626 of file sglStatelet.hpp.

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Member Function Documentation

void sglBlending::enable ( bool on ) [inline]

Enable or disable blending. Parameters: on   True to enable and false to disable. Definition at line 631 of file sglStatelet.hpp.

bool sglBlending::isEnabled ( ) const [inline]

Query whether or not blending is enabled. Returns: True if enabled and false if disabled. Definition at line 636 of file sglStatelet.hpp.

void sglBlending::setBlendFunc ( BlendFuncEnum src_func, BlendFuncEnum dst_func ) [inline]

Set the blend function factors for source and destination values. Parameters: src_func   The factor used on the source values (one of the BlendFuncEnum tokens). dst_func   The factor used on the destination values. Definition at line 643 of file sglStatelet.hpp.

void sglBlending::getBlendFunc ( BlendFuncEnum & src_func, BlendFuncEnum & dst_func ) const [inline]

Query the current blend function factors. Parameters: src_func   On return will contain the factor enum for source. dst_func   On return will contain the factor enum for destination. Definition at line 650 of file sglStatelet.hpp.

void sglBlending::apply ( sglCurrState * curr_state ) const [virtual]

Apply this state change to the current rendering state. Parameters: curr_state   Required for statelets that affect one another. For example the sglTransparency sets up depth mask and blending modes which interact with the sglBlending and sglDepthMask statelets, and the curr_state object is used to resolve these internal issues. Reimplemented from sglStatelet.

bool sglBlending::getSorted ( ) const [inline, virtual]

Query the sorting mode for this statelet. Returns: true if this type of statelet should be sorted by pointer rather than using m_index to index into an array. The defualt implementation is the latter, but if a statelet can take on an inordinate number of states (e.g. a floating point parameter) then true should be returned. Reimplemented from sglStatelet. Definition at line 657 of file sglStatelet.hpp.

virtual void sglBlending::printInfo ( ostream & ostrm, const char * indent_string ) const [virtual]

Output the state of this node to the specified ostream. Parameters: ostrm   the ostream to which the output is sent indent_string   the string (usually spaces) that is output at the beginning of every line of output Reimplemented from sglStatelet.

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

• sglStatelet.hpp

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