agxUtil::ConvexHull2D Class Reference

Utility class to create a convex hull in a plane given point cloud. More...

#include <ConvexHull2D.h>

Classes
struct	Point
	Point in hull containing the point projected onto the plane and the original point. More...

Public Types
using	const_iterator = HullContainer::const_iterator
using	Curve = PointCurve< Point >
using	CurveSegment = PointCurve< Point >::Segment
using	HullContainer = agx::VectorPOD< Point >

Public Member Functions
	ConvexHull2D ()
	Default constructor.
	ConvexHull2D (const agx::Vec3Vector &points, const agx::Plane &plane)
	Construct given point cloud and a plane.
	ConvexHull2D (const agx::Vec3Vector &points, const agx::Plane &plane, agx::UInt numSubQuadrangles)
	Construct given point cloud, plane and number of sub-quadrangles.
Curve	asCurve (agx::Bool closed=true) const
	Current hull as a curve object.
const Point &	back () const
const_iterator	begin () const
agx::Real	calculateArea () const
	Calculates the area of the hull - if the hull is present.
agx::Real	calculatePerimeter () const
	Computes the perimeter of the hull - if the hull is present.
const HullContainer &	computeHullJarvisMarch (const agx::Vec3Vector &points, const agx::Plane &plane)
	Computes the convex hull in the given plane using 2D gift wrapping algorithm - Jarvis march.
const HullContainer &	computeHullQuadrangles (const agx::Vec3Vector &points, const agx::Plane &plane, agx::UInt numSubQuadrangles)
	Computes the convex hull in the given plane using a set of quadrangles.
const_iterator	end () const
const Point &	front () const
const HullContainer &	getHull () const
const Point &	operator[] (agx::UInt index) const
	Access hull points of given index.
agx::UInt	size () const

Detailed Description

Utility class to create a convex hull in a plane given point cloud.

Definition at line 29 of file ConvexHull2D.h.

Member Typedef Documentation

const_iterator

using agxUtil::ConvexHull2D::const_iterator = HullContainer::const_iterator

Definition at line 45 of file ConvexHull2D.h.

Curve

using agxUtil::ConvexHull2D::Curve = PointCurve<Point>

Definition at line 46 of file ConvexHull2D.h.

CurveSegment

using agxUtil::ConvexHull2D::CurveSegment = PointCurve<Point>::Segment

Definition at line 47 of file ConvexHull2D.h.

HullContainer

using agxUtil::ConvexHull2D::HullContainer = agx::VectorPOD<Point>

Definition at line 44 of file ConvexHull2D.h.

Constructor & Destructor Documentation

ConvexHull2D() [1/3]

agxUtil::ConvexHull2D::ConvexHull2D

(

)

Default constructor.

ConvexHull2D() [2/3]

agxUtil::ConvexHull2D::ConvexHull2D	(	const agx::Vec3Vector &	points,
		const agx::Plane &	plane
	)

Construct given point cloud and a plane.

The hull will be calculated during construction using the Jarvis march algorithm.

Parameters

points	- original point cloud
plane	- plane to project point cloud onto

ConvexHull2D() [3/3]

agxUtil::ConvexHull2D::ConvexHull2D	(	const agx::Vec3Vector &	points,
		const agx::Plane &	plane,
		agx::UInt	numSubQuadrangles
	)

Construct given point cloud, plane and number of sub-quadrangles.

The hull will be calculated during construction using the Quadrangles algorithm.

Parameters

points	- original point cloud
plane	- plane to project point cloud onto
numSubQuadrangles	- number of sub quadrangles defining the accuracy of this algorithm (3 is very low and 100 is large and probably accurate)

Member Function Documentation

asCurve()

Curve agxUtil::ConvexHull2D::asCurve

(

agx::Bool

closed = true

)

const

Current hull as a curve object.

Parameters

closed

- true if the curve should be closed, i.e., first point == last point

Returns

current hull points as a curve object

back()

const ConvexHull2D::Point & agxUtil::ConvexHull2D::back ( ) const

inline

Returns

last element of the hull assuming the hull isn't empty

Definition at line 164 of file ConvexHull2D.h.

References agx::VectorPOD< T, Allocator >::back().

begin()

ConvexHull2D::const_iterator agxUtil::ConvexHull2D::begin ( ) const

inline

Returns

begin iterator of this hull

Definition at line 174 of file ConvexHull2D.h.

References agx::VectorPOD< T, Allocator >::begin().

calculateArea()

agx::Real agxUtil::ConvexHull2D::calculateArea

(

)

const

Calculates the area of the hull - if the hull is present.

If the hull is empty, i.e., number of points < 2, the area is 0.

Returns

area of the hull in the plane

calculatePerimeter()

agx::Real agxUtil::ConvexHull2D::calculatePerimeter

(

)

const

Computes the perimeter of the hull - if the hull is present.

If the hull is empty, i.e., number of points < 2, the perimeter is 0.

Returns

the perimeter of the hull in the plane

computeHullJarvisMarch()

const HullContainer & agxUtil::ConvexHull2D::computeHullJarvisMarch	(	const agx::Vec3Vector &	points,
		const agx::Plane &	plane
	)

Computes the convex hull in the given plane using 2D gift wrapping algorithm - Jarvis march.

Parameters

points	- original point cloud
plane	- plane to project point cloud onto

Returns

hull points if successful - otherwise an empty array

computeHullQuadrangles()

const HullContainer & agxUtil::ConvexHull2D::computeHullQuadrangles	(	const agx::Vec3Vector &	points,
		const agx::Plane &	plane,
		agx::UInt	numSubQuadrangles
	)

Computes the convex hull in the given plane using a set of quadrangles.

This approach can be much faster than the Jarvis march but points could be missed if numSubQuadrangles is too low. The lower number of sub-quadrangles the quicker this method will find a hull.

Parameters

points	- original point cloud
plane	- plane to project point cloud onto
numSubQuadrangles	- number of sub quadrangles defining the accuracy of this algorithm (3 is very low and 100 is large and probably accurate)

Returns

hull points if successful - otherwise an empty array

end()

ConvexHull2D::const_iterator agxUtil::ConvexHull2D::end ( ) const

inline

Returns

begin iterator of this hull

Definition at line 179 of file ConvexHull2D.h.

References agx::VectorPOD< T, Allocator >::end().

front()

const ConvexHull2D::Point & agxUtil::ConvexHull2D::front ( ) const

inline

Returns

first element of the hull assuming the hull isn't empty

Definition at line 159 of file ConvexHull2D.h.

References agx::VectorPOD< T, Allocator >::front().

getHull()

const HullContainer & agxUtil::ConvexHull2D::getHull

(

)

const

Returns

the hull (empty array if not created)

operator[]()

const ConvexHull2D::Point & agxUtil::ConvexHull2D::operator[] ( agx::UInt  index ) const

inline

Access hull points of given index.

No bounds checks make sure index < size().

Parameters

index

- hull point index

Returns

point with index index in the hull

Definition at line 154 of file ConvexHull2D.h.

size()

agx::UInt agxUtil::ConvexHull2D::size ( ) const

inline

Returns

number of points in the hull

Definition at line 169 of file ConvexHull2D.h.

References agx::Container::size().

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

• ConvexHull2D.h