Box3 Class Reference

#include <box3.h>

Public Member Functions
	Box3 ()
	Box3 (const Point3 &p, const Point3 &q)
void	Init ()
void	MakeCube (const Point3 &p, float side)
Point3	Min () const
Point3	Max () const
Point3	Center () const
Point3	Width () const
Point3	operator[] (int i) const
Box3 &	operator+= (const Point3 &p)
Box3 &	operator+= (const Box3 &b)
void	Scale (float s)
void	Translate (const Point3 &p)
void	EnlargeBy (float s)
void	IncludePoints (const Point3 *pts, int numpoints, Matrix3 *tm=nullptr)
Box3	operator* (const Matrix3 &tm) const
bool	operator== (const Box3 &b) const
bool	operator!= (const Box3 &b) const
bool	IsEmpty () const
bool	IsInitialized () const
bool	Contains (const Point3 &p) const
bool	Contains (const Box3 &b) const
bool	Intersects (const Box3 &b) const
bool	TriBoxOverlap (const Point3 vert0, const Point3 vert1, const Point3 vert2) const

Public Attributes
Point3	pmin
Point3	pmax

Detailed Description

See also

Class Point3, Class Matrix3.

Description:

This class represents a 3D box volume described by two 3D corner coordinates. Box3 provides methods that return individual coordinates of the box, scale and translate it, retrieve its center, modify its size, expand it to include points or other boxes, and determine if points are inside the box. All methods are implemented by the system.

Data Members:

Point3 pmin,pmax;

The corners of the 3D box.

Constructor & Destructor Documentation

Box3() [1/2]

Box3

(

)

Remarks

Constructor. The corners of the box are initialized such that the box is 'empty' and 'uninitialized'. See IsEmpty() and IsInitialized().

Box3() [2/2]

Box3 ( const Point3 &  p, const Point3 &  q  )

inline

Remarks

Constructor. The corners of the box are initialized to the points passed. pmin=p; pmax = q.

    {
        pmin = p;
        pmax = q;
    }

Member Function Documentation

Init()

void Init

(

)

Remarks

Initializes this box such that pmin is a very large value while pmax is a small value. Thus the box is 'empty' and 'uninitialized'. See IsEmpty() and IsInitialized().

MakeCube()

void MakeCube	(	const Point3 &	p,
		float	side
	)

Remarks

Modifies this box such that half the side length is subtracted from pmin and added to pmax. This creates a cube with the specified center p and side length side.

Parameters:

const Point3& p

Specifies the center point of the cube.

float side

Specifies the side length.

Min()

Point3 Min ( ) const

inline

Remarks

Returns the value of corner pmin.

    {
        return pmin;
    }

Max()

Point3 Max ( ) const

inline

Remarks

Returns the value of corner pmax.

    {
        return pmax;
    }

Center()

Point3 Center ( ) const

inline

Remarks

Returns the center of this Box3 as a Point3.

    {
        return (pmin + pmax) / (float)2.0;
    }

Width()

Point3 Width ( ) const

inline

Remarks

Returns the width of the box as a Point3. This is pmax-pmin.

    {
        return (pmax - pmin);
    }

operator[]()

Point3 operator[]

(

int

i

)

const

Remarks

Operator[] returns the 'i-th' corner point:

Mapping : X Y Z

[0] : (min,min,min)

[1] : (max,min,min)

[2] : (min,max,min)

[3] : (max,max,min)

[4] : (min,min,max)

[5] : (max,min,max)

[6] : (min,max,max)

[7] : (max,max,max)

Parameters:

int i

Specifies the corner to retrieve (0 <= i <= 7)

Returns

The 'i-th' corner point as a Point3.

operator+=() [1/2]

Box3 & operator+=

(

const Point3 &

p

)

Remarks

Expands this Box3 to include the Point3 p.

Parameters:

const Point3& p

Specifies the point to expand the box to include.

operator+=() [2/2]

Box3 & operator+=

(

const Box3 &

b

)

Remarks

Expands this Box3 to include the Box3 b.

Parameters:

const Box3& b

Specifies the Box3 to expand this box to include.

Scale()

void Scale

(

float

s

)

Remarks

Scales this box about its center by the specified scale.

Parameters:

float s

Specifies the scale factor for this Box3.

Translate()

void Translate

(

const Point3 &

p

)

Remarks

Translates this box by the distance specified. The point is added to each corner.

Parameters:

const Point3 &p

Specifies the distance to translate the box.

EnlargeBy()

void EnlargeBy

(

float

s

)

Remarks

Enlarges this box. A Point3 is created from s as Point3(s,s,s) and added to pmax and subtracted from pmin. If the box is 'empty', the box is centered at (0,0,0) and then enlarged.

IncludePoints()

void IncludePoints	(	const Point3 *	pts,
		int	numpoints,
		Matrix3 *	tm = nullptr
	)

operator*()

Box3 operator*

(

const Matrix3 &

tm

)

const

Remarks

Returns a box that bounds the 8 transformed corners of the input box.

Parameters:

const Matrix3& tm

Specifies the matrix to transform the box corners by.

operator==()

bool operator== ( const Box3 &  b ) const

inline

Remarks

Equality operator. Determines whether b is equal to this box. Returns nonzero if the boxes are equal; 0 otherwise.

    {
        return (pmin == b.pmin && pmax == b.pmax);
    }

operator!=()

bool operator!= ( const Box3 &  b ) const

inline

Remarks

Inequality operator. Determines whether b is different from this box. Returns true if the boxes are different.

    {
        return !(operator==(b));
    }

IsEmpty()

bool IsEmpty

(

)

const

Remarks

Determines if the box is empty. A box is considered empty if any component value of pmin is greater than the corresponding component value of pmax.

Returns

true if the box is empty; otherwise false.

IsInitialized()

bool IsInitialized

(

)

const

Remarks

Determines if the box is initialized. This indicates the box has had specific values set by the developer.

Returns

true if the box is initialized; otherwise false.

Contains() [1/2]

bool Contains

(

const Point3 &

p

)

const

Remarks

Determines if the specified point p is contained in this box.

Parameters:

const Point3& p

Specifies the point to check.

Returns

true if the specified point is contained in this box; otherwise false.

Contains() [2/2]

bool Contains

(

const Box3 &

b

)

const

Remarks

Determines if the specified Box3 is contained totally within this box.

Parameters:

const Box3& b

Specifies the box to check.

Returns

true if the specified box is entirely contained within this box; otherwise false.

Operators:

Intersects()

bool Intersects

(

const Box3 &

b

)

const

Remarks

Determines if the specified Box3 intersects this box.

Parameters:

const Box3& b

Specifies the box to check.

Returns

true if the specified Box3 intersects this box; otherwise false.

Operators:

TriBoxOverlap()

bool TriBoxOverlap	(	const Point3	vert0,
		const Point3	vert1,
		const Point3	vert2
	)		const

Remarks

Determines if the triangle specified by the tree points vert0, vert1, vert2 is overlapping with this box.

Returns

true if the specified triangle overlaps with this box in some way; otherwise false.

Member Data Documentation

pmin

Point3 pmin

pmax

Point3 pmax