Implementation of an Axis Aligned Bounding Box. More...

#include <Acts/Utilities/BoundingBox.hpp>

Inheritance diagram for Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >:

Public Types
using	entity_type = entity_t
	Type of stored entity.
using	Size = NamedType<VertexType, struct SizeParameter>
	Strong type to select the correct constructor.
using	transform_type = Eigen::Transform<value_type, DIM, Eigen::Affine>
	The transform type based on the value_type.
using	value_type = value_t
	The value type used by this class.
using	vertex_array_type = Eigen::Array<value_t, DIM, 1>
	Associated array value to VertexType.
using	VertexType = Eigen::Matrix<value_t, DIM, 1>
	Re-export vertex type based on value type given.

Public Member Functions
	AxisAlignedBoundingBox (const entity_t *entity, const VertexType &center, const Size &size)
	Constructor from a center position, and a width and height.
	AxisAlignedBoundingBox (const entity_t *entity, const VertexType &vmin, const VertexType &vmax)
	Constructor from an entity pointer, and the min and max vertices.
	AxisAlignedBoundingBox (const self_t &other)=default
	Copy constructor from other bounding box.
	AxisAlignedBoundingBox (const std::vector< self_t * > &boxes, vertex_array_type envelope=vertex_array_type::Zero())
	Constructor from a list of child boxes.
const VertexType &	center () const
	Get the center position of this bounding box.
void	draw (IVisualization3D &helper, Color color={120, 120, 120}, const transform_type &trf=transform_type::Identity()) const
	Draw this bounding box using the given visualization helper.
const entity_t *	entity () const
	Return the entity associated with this box.
const self_t *	getLeftChild () const
	Get the left child (i.e.
const self_t *	getSkip () const
	Get the skip node for this box.
bool	hasEntity () const
	Check whether this node as an associated entity.
template<std::size_t sides>
bool	intersect (const Frustum< value_type, DIM, sides > &fr) const
	Check if a frustum intersects with this bounding box.
bool	intersect (const Ray< value_type, DIM > &ray) const
	Implements the slab method for Ray/AABB intersections.
bool	intersect (const VertexType &point) const
	Calculate whether a point is inside this box.
const VertexType &	max () const
	Get the maximum vertex.
const VertexType &	min () const
	Get the minimum vertex.
AxisAlignedBoundingBox &	operator= (const self_t &other)=default
	Copy assignment operator from other bounding box.
void	setEntity (const entity_t *entity)
	Set the entity associated with with this box.
void	setSkip (self_t *skip)
	Set the skip node (bounding box).
std::ostream &	svg (std::ostream &os, value_type w, value_type h, value_type unit=10, const std::string &label="", const std::string &fillcolor="grey") const
	Draw this bounding box as SVG.
std::ostream &	toStream (std::ostream &os) const
	Write information about this bounding box to a stream.
void	transform (const transform_type &trf)
	Transforms this bounding box using the given transform.
self_t	transformed (const transform_type &trf) const
	Transforms this bounding box using the given transform.

Static Public Member Functions
static std::pair< VertexType, VertexType >	wrap (const std::vector< const self_t * > &boxes, vertex_array_type envelope=vertex_array_type::Zero())
	Helper function to calculate the size of a bounding box enclosing `boxes`.
static std::pair< VertexType, VertexType >	wrap (const std::vector< self_t * > &boxes, vertex_array_type envelope=vertex_array_type::Zero())
	Helper function to calculate the size of a bounding box enclosing `boxes`.
static std::pair< VertexType, VertexType >	wrap (const std::vector< self_t > &boxes, vertex_array_type envelope=vertex_array_type::Zero())
	Helper function to calculate the size of a bounding box enclosing `boxes`.

Static Public Attributes
static const std::size_t	dim = DIM
	Re-export dimension from template parameter.

Detailed Description

template<typename entity_t, typename value_t, std::size_t DIM>
class Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >

Implementation of an Axis Aligned Bounding Box.

This type is compatible with 2D and 3D boxes

Member Typedef Documentation

◆ entity_type

template<typename entity_t, typename value_t, std::size_t DIM>

using Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::entity_type = entity_t

Type of stored entity.

◆ Size

template<typename entity_t, typename value_t, std::size_t DIM>

using Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::Size = NamedType<VertexType, struct SizeParameter>

Strong type to select the correct constructor.

◆ transform_type

template<typename entity_t, typename value_t, std::size_t DIM>

using Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::transform_type = Eigen::Transform<value_type, DIM, Eigen::Affine>

The transform type based on the value_type.

◆ value_type

template<typename entity_t, typename value_t, std::size_t DIM>

using Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::value_type = value_t

The value type used by this class.

◆ vertex_array_type

template<typename entity_t, typename value_t, std::size_t DIM>

using Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::vertex_array_type = Eigen::Array<value_t, DIM, 1>

Associated array value to VertexType.

◆ VertexType

template<typename entity_t, typename value_t, std::size_t DIM>

using Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::VertexType = Eigen::Matrix<value_t, DIM, 1>

Re-export vertex type based on value type given.

Constructor & Destructor Documentation

◆ AxisAlignedBoundingBox() [1/4]

template<typename entity_t, typename value_t, std::size_t DIM>

Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::AxisAlignedBoundingBox ( const self_t & other )

default

Copy constructor from other bounding box.

Parameters

other The other bounding box to copy from

◆ AxisAlignedBoundingBox() [2/4]

template<typename entity_t, typename value_t, std::size_t DIM>

Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::AxisAlignedBoundingBox	(	const entity_t *	entity,
		const VertexType &	vmin,
		const VertexType &	vmax )

Constructor from an entity pointer, and the min and max vertices.

Parameters

entity	The entity to store
vmin	The minimum vertex.
vmax	The maximum vertex.

◆ AxisAlignedBoundingBox() [3/4]

template<typename entity_t, typename value_t, std::size_t DIM>

Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::AxisAlignedBoundingBox	(	const entity_t *	entity,
		const VertexType &	center,
		const Size &	size )

Constructor from a center position, and a width and height.

Parameters

entity	The entity to store
center	The center position
size	The size (width and height) of the box.

Note: The special type size is required to disambiguate this constructor from the other one above. It is a wrapper around a simple Vector3.

◆ AxisAlignedBoundingBox() [4/4]

template<typename entity_t, typename value_t, std::size_t DIM>

Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::AxisAlignedBoundingBox	(	const std::vector< self_t * > &	boxes,
		vertex_array_type	envelope = vertex_array_type::Zero() )

explicit

Constructor from a list of child boxes.

This box will wrap around all boxes contained in boxes, and additional envelope can be given.

Parameters

boxes	Vector of child boxes to store in this bounding box.
envelope	Envelope that will be added/subtracted to the dimension.

Member Function Documentation

◆ center()

template<typename entity_t, typename value_t, std::size_t DIM>

const VertexType & Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::center ( ) const

Get the center position of this bounding box.

Returns: The center position

◆ draw()

template<typename entity_t, typename value_t, std::size_t DIM>

void Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::draw	(	IVisualization3D &	helper,
		Color	color = {120, 120, 120},
		const transform_type &	trf = transform_type::Identity() ) const

Draw this bounding box using the given visualization helper.

This method is only available for the 3D case.

Parameters

helper	The visualization helper to write to
color	The color to use for drawing
trf	An optional transform to apply first.

◆ entity()

template<typename entity_t, typename value_t, std::size_t DIM>

const entity_t * Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::entity ( ) const

Return the entity associated with this box.

This might be nullptr if there is no entity attached.

Returns: The entity pointer, might be nullptr

◆ getLeftChild()

template<typename entity_t, typename value_t, std::size_t DIM>

const self_t * Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::getLeftChild ( ) const

Get the left child (i.e.

the first of the children that are inside this bounding box).

Returns: The lest most child.

◆ getSkip()

template<typename entity_t, typename value_t, std::size_t DIM>

const self_t * Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::getSkip ( ) const

Get the skip node for this box.

Returns: The skip node pointer

◆ hasEntity()

template<typename entity_t, typename value_t, std::size_t DIM>

bool Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::hasEntity ( ) const

Check whether this node as an associated entity.

If it does not have one, this is a purely abstract container box.

Returns: Whether the box has an entity attached.

◆ intersect() [1/3]

template<typename entity_t, typename value_t, std::size_t DIM>

template<std::size_t sides>

bool Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::intersect ( const Frustum< value_type, DIM, sides > & fr ) const

Check if a frustum intersects with this bounding box.

This method implements an algorithm similar to the one described in "Optimized View Frustum Culling Algorithms for Bounding Boxes (2012)" [2] (https://doi.org/10.1080/10867651.2000.10487517), but drops some of the more sophisticated optimization.

Parameters

fr	The frustum

Returns: Whether the frustum intersects this AABB

◆ intersect() [2/3]

template<typename entity_t, typename value_t, std::size_t DIM>

bool Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::intersect ( const Ray< value_type, DIM > & ray ) const

Implements the slab method for Ray/AABB intersections.

See https://tavianator.com/fast-branchless-raybounding-box-intersections/, https://tavianator.com/fast-branchless-raybounding-box-intersections-part-2-nans/, https://medium.com/@bromanz/another-view-on-the-classic-ray-aabb-intersection-algorithm-for-bvh-traversal-41125138b525 The original algorithms is described in "Graphics Gems (1990)" [1] (https://doi.org/10.1016/B978-0-08-050753-8.50084-X)

Note: This implementation may treat parallel rays on any of the slabs as outside due to how NaNs are handled by Eigen. See https://eigen.tuxfamily.org/bz/show_bug.cgi?id=564

Parameters

ray	The ray to intersect with

Returns: Whether the ray intersects this AABB

◆ intersect() [3/3]

template<typename entity_t, typename value_t, std::size_t DIM>

bool Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::intersect ( const VertexType & point ) const

Calculate whether a point is inside this box.

Parameters

point The point to test.

Returns: Whether the point is inside or not.

◆ max()

template<typename entity_t, typename value_t, std::size_t DIM>

const VertexType & Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::max ( ) const

Get the maximum vertex.

Returns: The maximum vertex

◆ min()

template<typename entity_t, typename value_t, std::size_t DIM>

const VertexType & Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::min ( ) const

Get the minimum vertex.

Returns: The minimum vertex

◆ operator=()

template<typename entity_t, typename value_t, std::size_t DIM>

AxisAlignedBoundingBox & Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::operator= ( const self_t & other )

default

Copy assignment operator from other bounding box.

Parameters

other The other AABB

Returns: Reference to this bounding box after copying

◆ setEntity()

template<typename entity_t, typename value_t, std::size_t DIM>

void Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::setEntity ( const entity_t * entity )

Set the entity associated with with this box.

Parameters

entity The entity

◆ setSkip()

template<typename entity_t, typename value_t, std::size_t DIM>

void Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::setSkip ( self_t * skip )

Set the skip node (bounding box).

Parameters

skip	The target skip node pointer

◆ svg()

template<typename entity_t, typename value_t, std::size_t DIM>

std::ostream & Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::svg	(	std::ostream &	os,
		value_type	w,
		value_type	h,
		value_type	unit = 10,
		const std::string &	label = "",
		const std::string &	fillcolor = "grey" ) const

Draw this bounding box as SVG.

This method is only available for the 2D case.

Parameters

os	The output stream to write to
w	The width of the output SVG.
h	The height of the output SVG.
unit	A scale factor to apply before drawing
label	A label to put next to the box.
fillcolor	Color to fill the box with.

Returns: The outstream given in os.

◆ toStream()

template<typename entity_t, typename value_t, std::size_t DIM>

std::ostream & Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::toStream ( std::ostream & os ) const

Write information about this bounding box to a stream.

Parameters

os	The output stream.

Returns: The stream given as an argument.

◆ transform()

template<typename entity_t, typename value_t, std::size_t DIM>

void Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::transform ( const transform_type & trf )

Transforms this bounding box using the given transform.

This method modifies the box it is called on.

Parameters

trf	The transform

◆ transformed()

template<typename entity_t, typename value_t, std::size_t DIM>

self_t Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::transformed ( const transform_type & trf ) const

Transforms this bounding box using the given transform.

This method returns a copy of this box, with the transformation applied, and leaves this instance unchanged.

Parameters

trf	The transform

Returns: The transformed bounding box

◆ wrap() [1/3]

template<typename entity_t, typename value_t, std::size_t DIM>

std::pair< VertexType, VertexType > Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::wrap	(	const std::vector< const self_t * > &	boxes,
		vertex_array_type	envelope = vertex_array_type::Zero() )

static

Helper function to calculate the size of a bounding box enclosing boxes.

Parameters

boxes	The boxes to wrap (const pointers)
envelope	Optional envelop to add/subtract to dimension.

Returns: Pair of vertices: min and max.

◆ wrap() [2/3]

template<typename entity_t, typename value_t, std::size_t DIM>

std::pair< VertexType, VertexType > Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::wrap	(	const std::vector< self_t * > &	boxes,
		vertex_array_type	envelope = vertex_array_type::Zero() )

static

Helper function to calculate the size of a bounding box enclosing boxes.

Overload which accepts non-const boxes in boxes.

Parameters

boxes	The boxes to wrap (non-const pointers)
envelope	Optional envelop to add/subtract to dimension.

Returns: Pair of vertices: min and max.

◆ wrap() [3/3]

template<typename entity_t, typename value_t, std::size_t DIM>

std::pair< VertexType, VertexType > Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::wrap	(	const std::vector< self_t > &	boxes,
		vertex_array_type	envelope = vertex_array_type::Zero() )

static

Helper function to calculate the size of a bounding box enclosing boxes.

Overload which accepts a vector in boxes which owns the instances

Parameters

boxes	The boxes to wrap (by-value vector)
envelope	Optional envelop to add/subtract to dimension.

Returns: Pair of vertices: min and max.

Member Data Documentation

◆ dim

template<typename entity_t, typename value_t, std::size_t DIM>

const std::size_t Acts::AxisAlignedBoundingBox< entity_t, value_t, DIM >::dim = DIM

static

Re-export dimension from template parameter.

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Detailed Description

Member Typedef Documentation

◆ entity_type

◆ Size

◆ transform_type

◆ value_type

◆ vertex_array_type

◆ VertexType

Constructor & Destructor Documentation

◆ AxisAlignedBoundingBox() [1/4]

◆ AxisAlignedBoundingBox() [2/4]

◆ AxisAlignedBoundingBox() [3/4]

◆ AxisAlignedBoundingBox() [4/4]

Member Function Documentation

◆ center()

◆ draw()

◆ entity()

◆ getLeftChild()

◆ getSkip()

◆ hasEntity()

◆ intersect() [1/3]

◆ intersect() [2/3]

◆ intersect() [3/3]

◆ max()

◆ min()

◆ operator=()

◆ setEntity()

◆ setSkip()

◆ svg()

◆ toStream()

◆ transform()

◆ transformed()

◆ wrap() [1/3]

◆ wrap() [2/3]

◆ wrap() [3/3]

Member Data Documentation

◆ dim