tlp::BoundingBox Struct Reference

#include <BoundingBox.h>

Inherits tlp::Array< Vec3f, 2 >.

Public Member Functions
	BoundingBox ()
	BoundingBox (const tlp::Vec3f &min, const tlp::Vec3f &max)
Vec3f	center () const
bool	contains (const tlp::Vec3f &coord) const
float	depth () const
void	expand (const tlp::Vec3f &coord)
void	getCompleteBB (Vec3f bb[8]) const
float	height () const
bool	intersect (const tlp::BoundingBox &boundingBox) const
bool	intersect (const Vec3f &segStart, const Vec3f &segEnd) const
bool	isValid () const
void	scale (const tlp::Vec3f &factor)
void	translate (const tlp::Vec3f &vec)
float	width () const
Public Member Functions inherited from tlp::Array< Vec3f, 2 >
Vec3f	operator[] (const unsigned int i) const
Vec3f &	operator[] (const unsigned int i)

Additional Inherited Members
Public Attributes inherited from tlp::Array< Vec3f, 2 >
Vec3f	array [SIZE]

Detailed Description

This class represents the 3D bounding box of an object. It is mostly used to determine whether or not two object are in a state of collision.

It is defined by two 3d points, the first one (A) being the lowest point, the second (B) being the highest. As a bounding box is a mathematical entity describing the lowest and highest points, whether these points are in the top-left corner or lower-right corner depends on the axes we use. Below is a crude ASCII-art description of the axes we use in our 3D world and the points where the min and max are thus positioned. Through the rest of this class's documentation, it will be assumed that this is the convention.

    y
   |
   |
   |_____ x
  /
 /
z

   _________ B
  /        /|
 /        / |
/________/  |
|        |  |
|        |  |
|        | /
|________|/
A

Author : Tulip team

Definition at line 63 of file BoundingBox.h.

Constructor & Destructor Documentation

tlp::BoundingBox::BoundingBox

(

)

Creates an invalid boundig box. The minimum is (1, 1, 1) and the maximum is (-1, -1, -1).

tlp::BoundingBox::BoundingBox	(	const tlp::Vec3f &	min,
		const tlp::Vec3f &	max
	)

Creates a bounding box that must be valid. Validity is checked in debug mode by an assert.

Parameters

min	The lower left closest point of the box.
max	The higher left most farther point of the box.

Member Function Documentation

Vec3f tlp::BoundingBox::center

(

)

const

Returns the geometrical center of the bounding box. An assertion is raised in debug mode if the BoundingBox is not valid.

Returns

The center of the bounding box :Vec3f

bool tlp::BoundingBox::contains

(

const tlp::Vec3f &

coord

)

const

Checks if the given vector is inside the current bounding box. If the bounding box is invalid the result is always false.

Parameters

coord

A point in the 3D space.

Returns

bool Wether coord is in the bounding box.

float tlp::BoundingBox::depth

(

)

const

Returns the depth of the bounding box An assertion is raised in debug mode if the bounding box is not valid.

void tlp::BoundingBox::expand

(

const tlp::Vec3f &

coord

)

Expands the bounding box to one containing the vector passed as parameter. If the parameter is inside the bounding box, it remains unchanged.

Parameters

coord

A point in the 3D space we want the bounding box to encompass.

Returns

void

void tlp::BoundingBox::getCompleteBB

(

Vec3f

bb[8]

)

const

The vector passed as parameter is modified to contain the 8 points of the bounding box. The points are, in order : 0: lower leftmost closest point (the bounding box's minimum) 1: lower rightmost closest point 2: highest rightmost closest point 3: highest leftmost closest point 4: lower rightmost farthest point 5: lower rightmost farthest point 6: highest rightmost farthest point 7: highest leftmost farthest point.

Crude ASCII art again, sorry for your eyes.

   6_________ 7
   /|       /|
  / |      / |
3/__|_____/2 |
 |  |_____|__|
 |  /4    |  /5
 | /      | /
 |/_______|/
 0        1

Parameters

bb	A vector in which to put the points of the bounding box.

Returns

void

float tlp::BoundingBox::height

(

)

const

Returns the height of the bounding box An assertion is raised in debug mode if the bounding box is not valid.

bool tlp::BoundingBox::intersect

(

const tlp::BoundingBox &

boundingBox

)

const

Checks if the given bounding box intersect the current one. If one of the bounding box is invalid return false.

Parameters

boundingBox

The bounding box to compare with.

Returns

bool Wether the bounding boxes intersect.

bool tlp::BoundingBox::intersect	(	const Vec3f &	segStart,
		const Vec3f &	segEnd
	)		const

Checks if the bounding box intersects a given line segment. If the bounding box is invalid the result is always false.

Parameters

segStart	the start point of the line segment on which to check intersection
segEnd	the end point of the line segment on which to check intersection

Returns

bool Wether the line segment intersects the bounding box

bool tlp::BoundingBox::isValid

(

)

const

Checks whether the bounding box's lowest point is less than it's highest point. "Less Than" means axis-by-axis comparison, i.e. x1 < x2 && y1 < y2 && z1 < z2.

Returns

bool Whether this bounding box is valid.

void tlp::BoundingBox::scale

(

const tlp::Vec3f &

factor

)

Scales the bounding box, i.e. multiplying its components by a vector passed as parameter.

Parameters

factor

The factor vector to scale this bounding box by.

Returns

void

void tlp::BoundingBox::translate

(

const tlp::Vec3f &

vec

)

Translates the bounding box by the displacement given by the vector passed as parameter.

Parameters

vec	The displacement vector in 3D space to translate this bounding box by.

Returns

void

float tlp::BoundingBox::width

(

)

const

Returns the width of the bounding box An assertion is raised in debug mode if the BoundingBox is not valid.