Module org.dyn4j

Package org.dyn4j.geometry.decompose

Class Bayazit

Object

AbstractDecomposer

Bayazit

All Implemented Interfaces:

Decomposer

public class Bayazit
extends AbstractDecomposer
implements Decomposer

Implementation of the Bayazit convex decomposition algorithm for simple polygons.

This algorithm is a O(nr) complexity algorithm where n is the number of input vertices and r is the number of output convex polygons. This algorithm can achieve optimal decompositions, however this is not guaranteed.

Since:

2.2.0

Version:

5.0.0

Author:

William Bittle

See Also:

Bayazit

Constructor Summary

Constructors

Constructor	Description
Bayazit()

Method Summary

Modifier and Type	Method	Description
List<Convex>	decompose(Vector2... points)	Performs the decomposition on the given polygon returning a list of Convex shapes.
protected void	decomposePolygon(List<Vector2> polygon, List<Convex> polygons)	Internal recursive method to decompose the given polygon into convex sub-polygons.
protected boolean	getIntersection(Vector2 a1, Vector2 a2, Vector2 b1, Vector2 b2, Vector2 p)	Returns true if the given lines intersect and returns the intersection point in the p parameter.
protected boolean	isReflex(Vector2 p0, Vector2 p, Vector2 p1)	Returns true if the given vertex, b, is a reflex vertex.
protected boolean	left(Vector2 a, Vector2 b, Vector2 p)	Returns true if the given point p is to the left of the line created by a-b.
protected boolean	leftOn(Vector2 a, Vector2 b, Vector2 p)	Returns true if the given point p is to the left or on the line created by a-b.
protected boolean	right(Vector2 a, Vector2 b, Vector2 p)	Returns true if the given point p is to the right of the line created by a-b.
protected boolean	rightOn(Vector2 a, Vector2 b, Vector2 p)	Returns true if the given point p is to the right or on the line created by a-b.

Methods inherited from class AbstractDecomposer

decompose

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface Decomposer

decompose

Constructor Detail

Bayazit

public Bayazit()

Method Detail

decompose

public List<Convex> decompose(Vector2... points)

Description copied from interface: Decomposer

Performs the decomposition on the given polygon returning a list of Convex shapes.

Specified by:

decompose in interface Decomposer

Parameters:

points - the polygon vertices

Returns:

List<Convex>

decomposePolygon

protected void decomposePolygon(List<Vector2> polygon,
                                List<Convex> polygons)

Internal recursive method to decompose the given polygon into convex sub-polygons.

Parameters:

polygon - the polygon to decompose

polygons - the list to store the convex polygons resulting from the decomposition

isReflex

protected boolean isReflex(Vector2 p0,
                           Vector2 p,
                           Vector2 p1)

Returns true if the given vertex, b, is a reflex vertex.

A reflex vertex is a vertex who's interior angle is greater than 180 degrees.

Parameters:

p0 - the vertex to test

p - the previous vertex

p1 - the next vertex

Returns:

boolean

left

protected boolean left(Vector2 a,
                       Vector2 b,
                       Vector2 p)

Returns true if the given point p is to the left of the line created by a-b.

Parameters:

a - the first point of the line

b - the second point of the line

p - the point to test

Returns:

boolean

leftOn

protected boolean leftOn(Vector2 a,
                         Vector2 b,
                         Vector2 p)

Returns true if the given point p is to the left or on the line created by a-b.

Parameters:

a - the first point of the line

b - the second point of the line

p - the point to test

Returns:

boolean

right

protected boolean right(Vector2 a,
                        Vector2 b,
                        Vector2 p)

Returns true if the given point p is to the right of the line created by a-b.

Parameters:

a - the first point of the line

b - the second point of the line

p - the point to test

Returns:

boolean

rightOn

protected boolean rightOn(Vector2 a,
                          Vector2 b,
                          Vector2 p)

Returns true if the given point p is to the right or on the line created by a-b.

Parameters:

a - the first point of the line

b - the second point of the line

p - the point to test

Returns:

boolean

getIntersection

protected boolean getIntersection(Vector2 a1,
                                  Vector2 a2,
                                  Vector2 b1,
                                  Vector2 b2,
                                  Vector2 p)

Returns true if the given lines intersect and returns the intersection point in the p parameter.

Parameters:

a1 - the first point of the first line

a2 - the second point of the first line

b1 - the first point of the second line

b2 - the second point of the second line

p - the destination object for the intersection point

Returns:

boolean