Module org.dyn4j

Class HalfEllipse

• All Implemented Interfaces:
`DataContainer`, `Convex`, `Rotatable`, `Shape`, `Transformable`, `Translatable`

```public class HalfEllipse
extends AbstractShape
implements Convex, Shape, Transformable, DataContainer```
Implementation of an Half-Ellipse `Convex` `Shape`.

A half ellipse must have a width and height greater than zero and the height parameter is the height of the half.

This shape is only supported by the GJK collision detection algorithm.

An `UnsupportedOperationException` is thrown when this shape is used with SAT. If you are using or are planning on using the SAT collision detection algorithm, you can use the `Geometry.createPolygonalHalfEllipse(int, double, double)` method to create a half ellipse `Polygon` approximation. Another option is to use the GJK or your own collision detection algorithm for this shape only and use SAT on others.

Since:
3.1.7
Version:
5.0.0
Author:
William Bittle

• Fields inherited from class AbstractShape

`center, radius, userData`
• Constructor Summary

Constructors
Constructor Description
```HalfEllipse​(double width, double height)```
Minimal constructor.
• Method Summary

All Methods
Modifier and Type Method Description
`void` ```computeAABB​(Transform transform, AABB aabb)```
Computes the `AABB` from this `Shape` after applying the given transformation and places the result in the given `AABB`.
`boolean` ```contains​(Vector2 point, Transform transform, boolean inclusive)```
Returns true if the given point is inside this `Shape`.
`Mass` `createMass​(double density)`
Creates a `Mass` object using the geometric properties of this `Shape` and the given density.
`double` `getArea()`
Returns the total area of the `Shape`.
`Vector2[]` ```getAxes​(Vector2[] foci, Transform transform)```
Returns an array of separating axes to test for this `Shape`.
`Vector2` `getEllipseCenter()`
Returns the center of the ellipse.
`Feature` ```getFarthestFeature​(Vector2 vector, Transform transform)```
Returns the `Feature` farthest in the direction of the given vector.
`Vector2` ```getFarthestPoint​(Vector2 vector, Transform transform)```
Returns the point farthest in the direction of the given vector.
`Vector2[]` `getFoci​(Transform transform)`
Returns an array of world space foci points for circular curved edges.
`double` `getHalfWidth()`
Returns the half width.
`double` `getHeight()`
Returns the height.
`double` `getRadius​(Vector2 center)`
Returns the radius of the shape if the given point was the center for this shape.
`Rotation` `getRotation()`
`double` `getRotationAngle()`
`double` `getWidth()`
Returns the width.
`Interval` ```project​(Vector2 vector, Transform transform)```
Returns the `Interval` of this `Shape` projected onto the given `Vector2` given the `Transform`.
`void` ```rotate​(Rotation rotation, double x, double y)```
Rotates the object about the given point.
`String` `toString()`
`void` ```translate​(double x, double y)```
Translates the object the given amounts in the respective directions.
• Methods inherited from class AbstractShape

`computeAABB, contains, contains, createAABB, createAABB, getCenter, getRadius, getUserData, project, rotate, rotate, rotate, rotate, rotate, rotateAboutCenter, setUserData, translate`
• Methods inherited from class Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`
• Methods inherited from interface DataContainer

`getUserData, setUserData`
• Methods inherited from interface Rotatable

`rotate, rotate, rotate, rotate, rotate`
• Methods inherited from interface Shape

`computeAABB, contains, contains, createAABB, createAABB, getCenter, getRadius, project, rotateAboutCenter`
• Methods inherited from interface Translatable

`translate`
• Constructor Detail

• HalfEllipse

```public HalfEllipse​(double width,
double height)```
Minimal constructor.

This creates an axis-aligned half ellipse fitting inside a rectangle of the given width and height.

Parameters:
`width` - the width
`height` - the height of the half
Throws:
`IllegalArgumentException` - if either the width or height is less than or equal to zero
• Method Detail

• toString

`public String toString()`
Overrides:
`toString` in class `AbstractShape`
• getAxes

```public Vector2[] getAxes​(Vector2[] foci,
Transform transform)```
Returns an array of separating axes to test for this `Shape`.

The `foci` parameter is an array of circular focal points of the other `Shape`.

If foci points are given, this method will return the separating axes for this `Shape`'s voronoi regions also. The points in the foci array are assumed to be in world space.

The returned axes are normalized and in world space.

This method is not supported by this shape.

Specified by:
`getAxes` in interface `Convex`
Parameters:
`foci` - the world space points representing foci of curved `Shape`s; can be null
`transform` - the local to world space `Transform` of this `Convex` `Shape`
Returns:
`Vector2`[]
Throws:
`UnsupportedOperationException` - when called
• getFoci

`public Vector2[] getFoci​(Transform transform)`
Returns an array of world space foci points for circular curved edges.

This method returns null if the `Shape` has zero curved edges.

The returned points are in world space.

This method is not supported by this shape.

Specified by:
`getFoci` in interface `Convex`
Parameters:
`transform` - the local to world space `Transform` of this `Convex` `Shape`
Returns:
`Vector2`[]
Throws:
`UnsupportedOperationException` - when called
• getFarthestPoint

```public Vector2 getFarthestPoint​(Vector2 vector,
Transform transform)```
Description copied from interface: `Convex`
Returns the point farthest in the direction of the given vector. If two points are equally distant along the given `Vector2` the first one is used.

The returned point is in world space.

Specified by:
`getFarthestPoint` in interface `Convex`
Parameters:
`vector` - the direction
`transform` - the local to world space `Transform` of this `Convex` `Shape`
Returns:
`Vector2`
• getFarthestFeature

```public Feature getFarthestFeature​(Vector2 vector,
Transform transform)```
Description copied from interface: `Convex`
Returns the `Feature` farthest in the direction of the given vector.

The returned feature is in world space.

Specified by:
`getFarthestFeature` in interface `Convex`
Parameters:
`vector` - the direction
`transform` - the local to world space `Transform` of this `Convex` `Shape`
Returns:
`Feature`
• createMass

`public Mass createMass​(double density)`
Description copied from interface: `Shape`
Creates a `Mass` object using the geometric properties of this `Shape` and the given density.
Specified by:
`createMass` in interface `Shape`
Parameters:
`density` - the density in kg/m2
Returns:
`Mass` the `Mass` of this `Shape`
• getArea

`public double getArea()`
Description copied from interface: `Shape`
Returns the total area of the `Shape`.
Specified by:
`getArea` in interface `Shape`
Returns:
double

`public double getRadius​(Vector2 center)`
Description copied from interface: `Shape`
Returns the radius of the shape if the given point was the center for this shape.
Specified by:
`getRadius` in interface `Shape`
Parameters:
`center` - the center point
Returns:
double
• contains

```public boolean contains​(Vector2 point,
Transform transform,
boolean inclusive)```
Description copied from interface: `Shape`
Returns true if the given point is inside this `Shape`.

If the given point lies on an edge the behavior is determined by the inclusive parameter. Set to true to consider the point inside or contained, or false to consider it outside or not contained.

The given point is assumed to be in world space.

Specified by:
`contains` in interface `Shape`
Parameters:
`point` - world space point
`transform` - `Transform` for this `Shape`
`inclusive` - whether points on the edge of the shape should be considered inside
Returns:
boolean
• rotate

```public void rotate​(Rotation rotation,
double x,
double y)```
Description copied from interface: `Rotatable`
Rotates the object about the given point.
Specified by:
`rotate` in interface `Rotatable`
Overrides:
`rotate` in class `AbstractShape`
Parameters:
`rotation` - the `Rotation` representing the rotation amount
`x` - the x coordinate to rotate about
`y` - the y coordinate to rotate about
• translate

```public void translate​(double x,
double y)```
Description copied from interface: `Translatable`
Translates the object the given amounts in the respective directions.
Specified by:
`translate` in interface `Translatable`
Overrides:
`translate` in class `AbstractShape`
Parameters:
`x` - the translation in the x direction
`y` - the translation in the y direction
• getRotationAngle

`public double getRotationAngle()`
Returns:
• getRotation

`public Rotation getRotation()`
Returns:
the `Rotation` object that represents the local rotation
• getWidth

`public double getWidth()`
Returns the width.
Returns:
double
• getHeight

`public double getHeight()`
Returns the height.
Returns:
double
• getHalfWidth

`public double getHalfWidth()`
Returns the half width.
Returns:
double
• getEllipseCenter

`public Vector2 getEllipseCenter()`
Returns the center of the ellipse.
Returns:
`Vector2`