celeritas::BoundingBox< T > Class Template Reference

Axis-aligned bounding box. More...

#include <BoundingBox.hh>

Public Types
Type aliases
using	real_type = T
using	Real3 = Array< real_type, 3 >
using	Extents = Array< real_type, 2 >
using	Extents3 = Array< Extents, 3 >

Public Member Functions
constexpr	BoundingBox () noexcept
	Create a null bounding box.
	BoundingBox (Real3 const &lower, Real3 const &upper) noexcept(! 0)
	Create a non-null bounding box from two points.
	BoundingBox (Extents3 const &extents) noexcept(! 0)
	Create a non-null bounding box from lo/hi extents.
constexpr Real3 const &	lower () const
	Lower bbox coordinate.
constexpr Real3 const &	upper () const
	Upper bbox coordinate.
constexpr Real3 const &	point (Bound b) const noexcept(! 0)
	Access a bounding point.
constexpr real_type const &	point (Bound b, Axis ax) const &noexcept(! 0)
	Access a bounding point coordinate (const ref to support LDG)
constexpr real_type	point (Bound b, Axis ax) const &&noexcept(! 0)
	Access a bounding point coordinate.
constexpr	operator bool () const noexcept
	Whether the bbox contains any point in space.
constexpr void	shrink (Bound b, Axis ax, real_type p)
	Reduce (clip) the bounding box's extent along an axis.
constexpr void	grow (Bound b, Axis ax, real_type p)
	Increase (expand) the bounding box's extent along an axis.
constexpr void	grow (Axis ax, real_type p)
	Increase (expand) the bounding box's extent along an axis.

Static Public Member Functions
static BoundingBox	from_infinite () noexcept
	Create a bounding box with infinite extents.
static constexpr BoundingBox	from_unchecked (Real3 const &lower, Real3 const &upper) noexcept
	Create a bounding box from unchecked lower/upper points.
static constexpr BoundingBox	from_unchecked (Extents3 const &) noexcept
	Create a bounding box from unchecked lo/hi extents.

Friends
constexpr friend bool	operator== (BoundingBox const &lhs, BoundingBox const &rhs)
	Test equality of two bounding boxes.
constexpr friend bool	operator!= (BoundingBox const &lhs, BoundingBox const &rhs)
	Test inequality of two bounding boxes.
constexpr friend BoundingBox	ldg (BoundingBox const *bb) noexcept
	Allow loading via ldg.
std::ostream &	operator<< (std::ostream &os, BoundingBox const &bbox)
	Write box to a stream.

Detailed Description

template<class T = ::celeritas::real_type>
class celeritas::BoundingBox< T >

Axis-aligned bounding box.

Bounding boxes "contain" all points inside and on their faces. See is_inside in BoundingBoxUtils.hh .

The default bounding box is "null", which has at least one lower coordinate strictly greater than its upper coordinate: it evaluates to false . A null bounding box still has the ability to be unioned and intersected with other bounding boxes with the expected effect, but geometrical operations on it (center, surface area, volume) are prohibited.

A "degenerate" bounding box is one that is well-defined but has zero volume because at least one lower coordinate is equal to the corresponding upper coordinate. Any point on the surface of this bounding box is still "inside". It may have nonzero surface area but will have zero volume.

Constructor & Destructor Documentation

BoundingBox() [1/2]

template<class T >

constexpr celeritas::BoundingBox< T >::BoundingBox ( )

inlineconstexprnoexcept

Create a null bounding box.

This should naturally satisfy

calc_union(BBox{}, other) = other:

and

calc_intersection(BBox{}, other) = other;

BoundingBox() [2/2]

template<class T >

celeritas::BoundingBox< T >::BoundingBox ( Real3 const &  lo, Real3 const &  hi  )

inlinenoexcept

Create a non-null bounding box from two points.

The lower and upper points are allowed to be equal (an empty bounding box at a single point) but upper must not be less than lower.

Member Function Documentation

grow() [1/2]

template<class T >

constexpr void celeritas::BoundingBox< T >::grow ( Axis  ax, real_type  p  )

inlineconstexpr

Increase (expand) the bounding box's extent along an axis.

If the point is outside the box, the box is expanded so the given boundary is on that point. Otherwise no change is made.

Postcondition

If the box is non-null, some point on the axis is_inside the bounding box.

grow() [2/2]

template<class T >

constexpr void celeritas::BoundingBox< T >::grow ( Bound  b, Axis  ax, real_type  v  )

inlineconstexpr

Increase (expand) the bounding box's extent along an axis.

If the point is outside the box, the box is expanded so the given boundary is on that point. Otherwise no change is made.

operator bool()

template<class T >

constexpr celeritas::BoundingBox< T >::operator bool ( ) const

inlineexplicitconstexprnoexcept

Whether the bbox contains any point in space.

A null box contains no points, and a degenerate point/edge/face contains that point.

shrink()

template<class T >

constexpr void celeritas::BoundingBox< T >::shrink ( Bound  b, Axis  ax, real_type  v  )

inlineconstexpr

Reduce (clip) the bounding box's extent along an axis.

If the point is inside the box, the box is clipped so the given boundary is on that point. Otherwise no change is made.

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

• BoundingBox.hh