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SoState Class Reference

The SoState class manages the Coin scenegraph traversal state data. More...

#include <Inventor/misc/SoState.h>

List of all members.

Public Methods
	SoState (SoAction *action, const SoTypeList &enabledelements)
	~SoState (void)
SoAction *	getAction (void) const
SoElement *	getElement (const int stackindex)
const SoElement *	getConstElement (const int stackindex) const
void	push (void)
void	pop (void)
void	print (FILE *const file=stdout) const
SbBool	isElementEnabled (const int stackindex) const
int	getDepth (void) const
void	setCacheOpen (const SbBool flag)
SbBool	isCacheOpen (void) const
void	lazyEvaluate (void) const
SoElement *	getElementNoPush (const int stackindex) const

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Detailed Description

The SoState class manages the Coin scenegraph traversal state data.

The SoState class is used by actions derived from the SoAction class. It manages the scenegraph state as stacks of elements (ie instances of classes derived from SoElement).

For more information on the inner workings of traversal states in Coin, we recommend the book «The Inventor Toolmaker» (ISBN 0-201-62493-1).

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Constructor & Destructor Documentation

SoState::SoState (  SoAction * theAction, const SoTypeList & enabledelements )

The constructor. The theAction argument is the action object the state is part of, and the enabledElements argument is an SoTypeList of the elements that are enabled for this action. The constructor pushes a default element onto the indexes of all the enabled element stacks. SoElement::push() is not called on the initial elements in the SoState stacks, but SoElement::init() is.

SoState::~SoState (  void )

The destructor. Note that when destruction happens, lagging events caused by lazy evaluation won't be performed.

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Member Function Documentation

SoAction * SoState::getAction (  void )  const

This method returns the pointer to the action instance given to the constructor.

SoElement * SoState::getElement (  const int stackindex )

This method returns a modifyable instance of the element on the top of the stack with the given stackindex. Because of lazy programming, this function may need to do some work, so SoState::getConstElement() should be used instead whenever possible.

const SoElement * SoState::getConstElement (  const int stackindex )  const [inline]

This method returns a pointer to the top element of the given element stack. The element is read-only and must not be changed under any circumstances or strange side-effect will occur.

void SoState::push (  void )

This method pushes the state one level down. This saves the state so it can be changed and later restored to this state by calling SoState::pop(). The push and pop mechanism is performed lazily for efficiency reasons (avoids a lot of memory allocation and copying). Only when a state element is actually going to be changed, that element will be pushed for real.

void SoState::pop (  void )

This method pops the state to restore it to a previous state. Pops are performed eagerly but the code is very tight so there is no reason to worry about efficiency.

void SoState::print (  FILE *const file = stdout )  const

This method is just for debugging purposes.

SbBool SoState::isElementEnabled (  const int stackindex )  const

This method returns TRUE if the element with the given element stack index is enabled, and FALSE otherwise.

int SoState::getDepth (  void )  const

This method returns the current depth of the state stack. The depth is "virtual", not necessarily physical.

void SoState::setCacheOpen (  const SbBool open )

Controls whether a cache is open.

SbBool SoState::isCacheOpen (  void )  const

Returns whether a cache is open.

void SoState::lazyEvaluate (  void )  const

Evaluates (calls the virtual function lazyEvaluate()) for all lazy elements (isLazy() returns TRUE).

SoElement * SoState::getElementNoPush (  const int stackindex )  const

This method returns a pointer to a writable element without checking for state depth. Use with care.

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

• SoState.cpp
• SoState.h

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