BufferedBool Class Reference

#include <C:/Work/specialnumbers_svn/NumberLib/NumbersLib/BufferedBool.h>

Inheritance diagram for BufferedBool:

Detailed Description

This class can be used instead of a bool to get smoother (less eratic) transitions, that is, the value stays true or false longer.

It works as follows: an internal value is maintained. Every time this class is set to true, the value is increased; every time it is set to false, that value is reduced. When the value becomes larger than a certain threshold, the output value is switched to true. Similarly when the value becomes smaller than a certain threshold, the output value is switched to false. These two thresholds needn't (and in most cases shouldn't) be the same.

This class is supposed to mimick bools. However, assignement and other operators have not been overloaded so that this class won't be confused with an actual bool.

For example, suppose the internal float value is well below the threshold. Then the following code results print "false";

b.setValue(true) printf(b.getValue() ? "true" : "false");

If we overloaded the operators, we would get

b = false; printf(b ? "true" : "false");

which would be more confusing. The less convenient but explicit syntax reminds us that this is not pure bool, but something special.

Using with floating point

Consider this example:

      BufferedBool b(0.3f, 0.7f, 0.1f);

      for(int i = 0; i < 8; i++)
      {
         b.setValue(true);
         cout << b.getValue() << " ";
      }

This will print

   false false false false false false true true

instead of

   false false false false false false false true

This is because the top threshold is converted to .69999999 and adding the increment 0.1 seven times is to 0 gives 0.70000005, so the internal float becomes greater than the threshold one iteration too early. Never rely on exact transitions!

Author:: Herman Tulleken (herman.tulleken@gmail.com)
luma/games (http://www.luma.co.za/)

Definition at line 71 of file BufferedBool.h.


Public Member Functions
	BufferedBool (float bottomThreshold, float topThreshold, float increment=0.1f)
	Constructs a new BufferedBool.
void	forceValue (bool value)
	Forces the next value to be the given value.
float	getFloatValue () const
	Returns the internal float value that regulates the boolean value.
bool	getValue () const
	Returns the boolean value, which depends on which threshold was last triggered.
void	setIncrement (float increment)
	Sets the uincreemnt value for this buffered bool.
void	setValue (bool value, float ellapsedTime=1)
	The internal float is incremented if this is true, otherwise it is decremented.
Private Attributes
bool	mBoolValue
float	mBottomThreshold
ClampedNumber< float >	mFloatValue
float	mFrameTime
float	mTopThreshold

Constructor & Destructor Documentation

BufferedBool	(	float	bottomThreshold,
		float	topThreshold,
		float	increment = `0.1f`
	)

Constructs a new BufferedBool.

Parameters:

	bottomThreshold	if the internal float value drops below this point, the bool value next returned will be false.
	topThreshold	if the internal float value rises above this point, the bool value next returned will be true.
	increment	The value with which the internal float is adjusted each time setValue() is called.

Definition at line 8 of file BufferedBool.cpp.