gf::Polygon Class Reference

A convex polygon. More...

#include <gf/Polygon.h>

Inheritance diagram for gf::Polygon:

Public Member Functions
	Polygon ()=default
	Default constructor. More...
	Polygon (Span< const Vector2f > points)
	Constructor from an array. More...
template<typename Iterator >
	Polygon (Iterator first, Iterator last)
	Constructor from points. More...
Vector2f	getSupport (Vector2f direction, const Transform &transform) const
	Get the farthest point in a direction. More...
Vector2f	getSupport (Vector2f direction) const
	Get the farthest point in a direction. More...
bool	isConvex () const
	Check if the polygon is convex. More...
Winding	getWinding () const
	Compute the winding of a simple polygon. More...
bool	contains (Vector2f point) const
	Test if a point is inside the polygon. More...
float	getArea () const
	Compute the area of the polygon. More...
Vector2f	getPrevPoint (std::size_t i) const
	Get the point before the i-th point. More...
Vector2f	getNextPoint (std::size_t i) const
	Get the point after the i-th point. More...
Public Member Functions inherited from gf::PointSequence
	PointSequence ()=default
	Default constructor. More...
	PointSequence (Span< const Vector2f > points)
	Constructor from an array. More...
template<typename Iterator >
	PointSequence (Iterator first, Iterator last)
	Constructor from points. More...
bool	isEmpty () const
	Check if the sequence is empty. More...
void	addPoint (Vector2f point)
	Add a point to the sequence. More...
std::size_t	getPointCount () const
	Get the number of points of the sequence. More...
Vector2f	getPoint (std::size_t index) const
	Get the i-th point of the sequence. More...
Vector2f	getCenter () const
	Get the center of the sequence. More...
const Vector2f *	begin () const
	Get an iterator to the first point. More...
Vector2f *	begin ()
	Get an iterator to the first point. More...
const Vector2f *	end () const
	Get an iterator past the last point. More...
Vector2f *	end ()
	Get an iterator past the last point. More...
Vector2f	getFirstPoint () const
	Get the first point of the sequence. More...
Vector2f	getLastPoint () const
	Get the last point of the sequence. More...
void	applyTransform (const Matrix3f &mat)
	Apply a transformation to the sequence. More...
void	simplify (float distance=Epsilon)
	Simplify the sequence. More...
void	reverse ()
	Reverse the points in the sequence. More...

Additional Inherited Members
Protected Member Functions inherited from gf::PointSequence
std::vector< Vector2f > &	getRawPoints ()
	Get the raw container of points. More...
const std::vector< Vector2f > &	getRawPoints () const
	Get the raw container of points. More...

Detailed Description

A convex polygon.

Constructor & Destructor Documentation

Polygon() [1/3]

gf::Polygon::Polygon ( )

default

Default constructor.

Polygon() [2/3]

gf::Polygon::Polygon ( Span< const Vector2f >  points )

inline

Constructor from an array.

Parameters

points

The array of points

Polygon() [3/3]

template<typename Iterator >

gf::Polygon::Polygon ( Iterator  first, Iterator  last  )

inline

Constructor from points.

Parameters

first	Iterator to the first point
last	Iterator after the last point

Member Function Documentation

contains()

bool gf::Polygon::contains

(

Vector2f

point

)

const

Test if a point is inside the polygon.

Parameters

point

The point to test

Returns

True if the point is inside the polygon

getArea()

float gf::Polygon::getArea

(

)

const

Compute the area of the polygon.

Complexity: \( O(n) \)

Returns

The area of the polygon

getNextPoint()

Vector2f gf::Polygon::getNextPoint

(

std::size_t

i

)

const

Get the point after the i-th point.

Parameters

i	The index of the current point

Returns

The point after the current point

getPrevPoint()

Vector2f gf::Polygon::getPrevPoint

(

std::size_t

i

)

const

Get the point before the i-th point.

Parameters

i	The index of the current point

Returns

The point before the current point

getSupport() [1/2]

Vector2f gf::Polygon::getSupport

(

Vector2f

direction

)

const

Get the farthest point in a direction.

Parameters

direction

The direction to search

Returns

The farthest point of the polygon in the given direction

getSupport() [2/2]

Vector2f gf::Polygon::getSupport	(	Vector2f	direction,
		const Transform &	transform
	)		const

Get the farthest point in a direction.

Parameters

direction	The direction to search (in world coordinates)
transform	The transformation of the polygon

Returns

The farthest point of the polygon in the given direction

getWinding()

Winding gf::Polygon::getWinding

(

)

const

Compute the winding of a simple polygon.

Complexity: \( O(n) \)

Returns

The winding of the simple polygon

See also

gf::Winding

Curve orientation - Wikipedia

isConvex()

bool gf::Polygon::isConvex

(

)

const

Check if the polygon is convex.

This function should return true, otherwise you may have problems in other functions which assume that the polygon is convex.

This function does not handle self-intersecting polygons (yet).

Returns

True if the polygon is convex