Class EllipseCurve

Creates a 2d curve in the shape of an ellipse. Setting the xRadius equal to the yRadius will result in a circle.

Example

const curve = new EllipseCurve(
  0,  0,            // ax, aY
  10, 10,           // xRadius, yRadius
  0,  2 * Math.PI,  // aStartAngle, aEndAngle
  false,            // aClockwise
  0                 // aRotation
);

const points = curve.getPoints( 50 );

Hierarchy

Constructors

constructor

Properties

aClockwise aEndAngle aRotation aStartAngle aX aY arcLengthDivisions isArcCurve isCatmullRomCurve3 isCubicBezierCurve isCubicBezierCurve3 isEllipseCurve isLineCurve isLineCurve3 isQuadraticBezierCurve isQuadraticBezierCurve3 isSplineCurve type xRadius yRadius

Methods

clone computeFrenetFrames copy fromJSON getLength getLengths getPoint getPointAt getPoints getSpacedPoints getTangent getTangentAt getUtoTmapping toJSON updateArcLengths

Constructors

constructor

  • Create a new instance.

    Parameters

    • Optional x: number

      – The X center of the ellipse. Default is 0.

    • Optional y: number

      – The Y center of the ellipse. Default is 0.

    • Optional xRadius: number

      – The radius of the ellipse in the x direction. Default is 1.

    • Optional yRadius: number

      – The radius of the ellipse in the y direction. Default is 1.

    • Optional startAngle: number

      – The start angle of the curve in radians starting from the positive X axis. Default is 0.

    • Optional endAngle: number

      – The end angle of the curve in radians starting from the positive X axis. Default is 2 x Math.PI.

    • Optional isClockwise: boolean

      – Whether the ellipse is drawn clockwise. Default is false.

    • Optional rotation: number

      The rotation angle of the ellipse in radians, counterclockwise from the positive X axis (optional). Default is 0.

    Returns EllipseCurve

Properties

aClockwise

aClockwise: boolean

Whether the ellipse is drawn clockwise.

Default Value

false

aEndAngle

aEndAngle: number

The end angle of the curve in radians starting from the middle right side.

Default

2 * Math.PI

aRotation

aRotation: number

The rotation angle of the ellipse in radians, counterclockwise from the positive X axis

Default Value

0

aStartAngle

aStartAngle: number

The start angle of the curve in radians starting from the middle right side.

Default Value

0

aX

aX: number

The X center of the ellipse.

Default Value

0

aY

aY: number

The Y center of the ellipse.

Default Value

0

arcLengthDivisions

arcLengthDivisions: number

Determines the amount of divisions when calculating the cumulative segment lengths of a curve via .getLengths. To ensure precision when using methods like .getSpacedPoints, it is recommended to increase .arcLengthDivisions if the curve is very large.

Default

200

Readonly isArcCurve

isArcCurve: boolean

subclass should override

Default Value

false

Readonly isCatmullRomCurve3

isCatmullRomCurve3: boolean

subclass should override

Default Value

true

Readonly isCubicBezierCurve

isCubicBezierCurve: boolean

subclass should override

Default Value

false

Readonly isCubicBezierCurve3

isCubicBezierCurve3: boolean

subclass should override

Default Value

false

Readonly isEllipseCurve

isEllipseCurve: boolean

Default Value

true

Readonly isLineCurve

isLineCurve: boolean

subclass should override

Default Value

false

Readonly isLineCurve3

isLineCurve3: boolean

subclass should override

Default Value

false

Readonly isQuadraticBezierCurve

isQuadraticBezierCurve: boolean

subclass should override

Default Value

false

Readonly isQuadraticBezierCurve3

isQuadraticBezierCurve3: boolean

subclass should override

Default Value

false

Readonly isSplineCurve

isSplineCurve: boolean

subclass should override

Default Value

false

Readonly type

type: string

The print name of the EllipseCurve.

Default Value

'EllipseCurve'

xRadius

xRadius: number

The radius of the ellipse in the x direction.

Default Value

1

yRadius

yRadius: number

The radius of the ellipse in the y direction.

Default Value

1

Methods

clone

  • Creates a new instance with same property values as this curve.

    Returns

    A new Curve instance exactly like this curve.

    Returns Curve<Vector2>

computeFrenetFrames

  • Generates the Frenet frames. Learn more at http://www.cs.indiana.edu/pub/techreports/TR425.pdf

    Returns

    An object with shape: { tangents: Vector3[]; normals: Vector3[]; binormals: Vector3[]; }

    Parameters

    • segments: number

      Number of segments

    • Optional closed: boolean

      True if this curve is closed.

    Returns { binormals: Vector3[]; normals: Vector3[]; tangents: Vector3[] }

    • binormals: Vector3[]
    • normals: Vector3[]
    • tangents: Vector3[]

copy

fromJSON

getLength

getLengths

  • Get list of cumulative segment lengths.

    Returns

    Array of points

    Parameters

    • Optional divisions: number

    Returns number[]

getPoint

  • Find the point (vector) for point t of the curve where t is between 0 and 1.

    Returns

    The point.

    Parameters

    • t: number

      A position on the curve. Must be in the range [ 0, 1 ].

    • Optional optionalTarget: Vector2

      (optional) If specified, the result will be copied into this Vector, otherwise a new Vector will be created.

    Returns Vector2

getPointAt

  • Find a vector for point at relative position in curve according to arc length

    Returns

    The point.

    Parameters

    • u: number

      A position on the curve according to the arc length. Must be in the range [ 0, 1 ].

    • Optional optionalTarget: Vector2

      (optional) If specified, the result will be copied into this Vector, otherwise a new Vector will be created.

    Returns Vector2

getPoints

  • Compute a set of divisions + 1 points using getPoint( t ).

    Returns

    Array of point vectors.

    Parameters

    • Optional divisions: number

      number of pieces to divide the curve into. Default is 5.

    Returns Vector2[]

getSpacedPoints

  • Compute a set of divisions + 1 equi-spaced points using getPointAt( u ).

    Returns

    Array of point vectors.

    Parameters

    • Optional divisions: number

      number of pieces to divide the curve into. Default is 5.

    Returns Vector2[]

getTangent

  • Compute a unit vector tangent at t. If the subclassed curve do not implement its tangent derivation, 2 points a small delta apart will be used to find its gradient which seems to give a reasonable approximation getTangent(t: number, optionalTarget?: T): T;

    Returns

    A vector tangent to t.

    Parameters

    • t: number

      A position on the curve. Must be in the range [ 0, 1 ].

    • Optional optionalTarget: Vector2

      — (optional) If specified, the result will be copied into this Vector, otherwise a new Vector will be created.

    Returns Vector2

getTangentAt

  • Compute the tangent at a point which is equidistant to the ends of the curve from the point given in getTangent().

    Returns

    a vector tangent to u.

    Parameters

    • u: number

      A position on the curve according to the arc length. Must be in the range [ 0, 1 ].

    • Optional optionalTarget: Vector2

      (optional) If specified, the result will be copied into this Vector, otherwise a new Vector will be created.

    Returns Vector2

getUtoTmapping

  • Given u ( 0 .. 1 ), get a t to find p. This gives you points which are equi distance

    Parameters

    • u: number
    • distance: number

    Returns number

toJSON

  • Create a JSON object representation of this instance.

    Returns

    A JSON object

    Returns object

updateArcLengths

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