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VectorHash Class Reference

This is a hash of a (2-dimensional) Vector to allow for sorting of Obstacle s by using a square system. This is used by ObstacleGrid . More...

#include <obstacle_grid.h>

Inherited by _classes_ [private].

Inheritance diagram for VectorHash:

[legend]List of all members.

Public Methods
	operator unsigned int () const
	The constructor of this class only takes a Vector for an argument and converts that to hashval . More...
	VectorHash ()
void	operator= (const VectorHash &oth)
	VectorHash (const VectorHash &oth)
	VectorHash (const Vector &coord)
bool	operator== (const VectorHash &oth) const
	An equal comparism function between two VectorHash es. Since hashval is pre-calculated, all this function needs to do is check for equality. More...
bool	operator< (const VectorHash &oth) const
	A less than comparism function between two VectorHash es that allows for sorting. Since hashval is pre-calculated, all this function needs to do is check if our hashval is less than the other. More...
Static Public Methods
const float	shortWidth ()
	A constant unexact default for the width of a Surface . More...
Public Attributes
unsigned int	hashval
	hashval is the stored hash value used for hasty comparisms. More...
Static Public Attributes
const float	ScaleAmt = (float)(2.)
	this constant is one divided by the width/height of each 'square' used for collisions with Obstacle s. More...
Static Private Methods
float	frem (float a, float b)
	An internal remainder function that only returns a positive remainder between two floats. More...

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Detailed Description

This is a hash of a (2-dimensional) Vector to allow for sorting of Obstacle s by using a square system. This is used by ObstacleGrid .

VectorHash is a hash value used for fast sorting between (2-dimensional) Vector s. This class goes in a board x spaces forward and then y times a fake width for the Surface. This is allowed to be slightly in-accurate because of unlikeliness of getting the same number twice between the range of a short int.

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Constructor & Destructor Documentation

VectorHash::VectorHash (    )  [inline]

{ hashval=0; }

VectorHash::VectorHash (  const VectorHash &    oth )  [inline]

: hashval(oth.hashval) {}

VectorHash::VectorHash (  const Vector &    coord )  [inline]

{ Vector crd (coord.Scale(ScaleAmt)); hashval =((unsigned int)((frem(floor(crd.i),shortWidth()))+(shortWidth()*floor(crd.j)))); }

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Member Function Documentation

float VectorHash::frem (  float    a, float    b )  [inline, static, private]

An internal remainder function that only returns a positive remainder between two floats. { float ne=fmod(a,b); if (ne<0) { return b+ne; } else { return ne; } }

VectorHash::operator unsigned int (    )  const [inline]

The constructor of this class only takes a Vector for an argument and converts that to hashval . { return hashval; }

bool VectorHash::operator< (  const VectorHash &    oth )  const [inline]

A less than comparism function between two VectorHash es that allows for sorting. Since hashval is pre-calculated, all this function needs to do is check if our hashval is less than the other. { return hashval<oth.hashval; }

void VectorHash::operator= (  const VectorHash &    oth )  [inline]

{ hashval=oth.hashval; }

bool VectorHash::operator== (  const VectorHash &    oth )  const [inline]

An equal comparism function between two VectorHash es. Since hashval is pre-calculated, all this function needs to do is check for equality. { return hashval==oth.hashval; }

const float VectorHash::shortWidth (    )  [inline, static]

A constant unexact default for the width of a Surface . {return 65536-129;}

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Member Data Documentation

unsigned int VectorHash::hashval

hashval is the stored hash value used for hasty comparisms.

const float VectorHash::ScaleAmt = (float)(2.) [static]

this constant is one divided by the width/height of each 'square' used for collisions with Obstacle s.

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

• obstacle_grid.h

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