Class CurveUtility

A collection of methods for extracting information about BezierCurve types.

Inheritance

object

CurveUtility

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: UnityEngine.Splines

Assembly: Unity.Splines.dll

Syntax

public static class CurveUtility

Methods

ApproximateLength(BezierCurve)

Calculate the approximate length of a BezierCurve. This is less accurate than CalculateLength(BezierCurve, int), but can be significantly faster. Use this when accuracy is not paramount and the curve control points are changing frequently.

Declaration

public static float ApproximateLength(BezierCurve curve)

Parameters

Type	Name	Description
BezierCurve	curve	The BezierCurve to calculate length.

Returns

Type	Description
float	An estimate of the length of a curve.

CalculateCurveLengths(BezierCurve, NativeArray<DistanceToInterpolation>)

Populate a pre-allocated lookupTable array with distance to 't' values. The number of table entries is dependent on the size of the passed lookupTable.

Declaration

public static void CalculateCurveLengths(BezierCurve curve, NativeArray<DistanceToInterpolation> lookupTable)

Parameters

Type	Name	Description
BezierCurve	curve	The BezierCurve to create a distance to 't' lookup table for.
NativeArray<DistanceToInterpolation>	lookupTable	A pre-allocated native array to populate with distance to interpolation ratio data.

CalculateCurveLengths(BezierCurve, DistanceToInterpolation[])

Populate a pre-allocated lookupTable array with distance to 't' values. The number of table entries is dependent on the size of the passed lookupTable.

Declaration

public static void CalculateCurveLengths(BezierCurve curve, DistanceToInterpolation[] lookupTable)

Parameters

Type	Name	Description
BezierCurve	curve	The BezierCurve to create a distance to 't' lookup table for.
DistanceToInterpolation[]	lookupTable	A pre-allocated array to populate with distance to interpolation ratio data.

CalculateLength(BezierCurve, int)

Calculate the length of a BezierCurve by unrolling the curve into linear segments and summing the lengths of the lines. This is equivalent to accessing GetCurveLength(int).

Declaration

public static float CalculateLength(BezierCurve curve, int resolution = 30)

Parameters

Type	Name	Description
BezierCurve	curve	The BezierCurve to calculate length.
int	resolution	The number of linear segments used to calculate the curve length.

Returns

Type	Description
float	The sum length of a collection of linear segments fitting this curve.

See Also

ApproximateLength(BezierCurve)

EvaluateAcceleration(BezierCurve, float)

Given a Bezier curve, return an interpolated acceleration at ratio t.

Declaration

public static float3 EvaluateAcceleration(BezierCurve curve, float t)

Parameters

Type	Name	Description
BezierCurve	curve	A cubic Bezier curve.
float	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
float3	An acceleration vector on the curve.

EvaluateCurvature(BezierCurve, float)

Given a Bezier curve, return an interpolated curvature at ratio t.

Declaration

public static float EvaluateCurvature(BezierCurve curve, float t)

Parameters

Type	Name	Description
BezierCurve	curve	A cubic Bezier curve.
float	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
float	A curvature value on the curve.

EvaluatePosition(BezierCurve, float)

Given a Bezier curve, return an interpolated position at ratio t.

Declaration

public static float3 EvaluatePosition(BezierCurve curve, float t)

Parameters

Type	Name	Description
BezierCurve	curve	A cubic Bezier curve.
float	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
float3	A position on the curve.

EvaluateTangent(BezierCurve, float)

Given a Bezier curve, return an interpolated tangent at ratio t.

Declaration

public static float3 EvaluateTangent(BezierCurve curve, float t)

Parameters

Type	Name	Description
BezierCurve	curve	A cubic Bezier curve.
float	t	A value between 0 and 1 representing the ratio along the curve.

Returns

Type	Description
float3	A tangent on the curve.

GetDistanceToInterpolation(BezierCurve, float)

Gets the normalized interpolation, (t), that corresponds to a distance on a BezierCurve.

Declaration

public static float GetDistanceToInterpolation(BezierCurve curve, float distance)

Parameters

Type	Name	Description
BezierCurve	curve	The BezierCurve to calculate the distance to interpolation ratio for.
float	distance	The curve-relative distance to convert to an interpolation ratio (also referred to as 't').

Returns

Type	Description
float	Returns the normalized interpolation ratio associated to distance on the designated curve.

Remarks

It is inefficient to call this method frequently. For better performance create a DistanceToInterpolation cache with CalculateCurveLengths(BezierCurve, DistanceToInterpolation[]) and use the overload of this method which accepts a lookup table.

GetDistanceToInterpolation<T>(T, float)

Return the normalized interpolation (t) corresponding to a distance on a BezierCurve. This method accepts a look-up table (referred to in code with acronym "LUT") that may be constructed using CalculateCurveLengths(BezierCurve, DistanceToInterpolation[]). The built-in Spline class implementations (Spline and NativeSpline) cache these look-up tables internally.

Declaration

public static float GetDistanceToInterpolation<T>(T lut, float distance) where T : IReadOnlyList<DistanceToInterpolation>

Parameters

Type	Name	Description
T	lut	A look-up table of distance to 't' values. See CalculateCurveLengths(BezierCurve, DistanceToInterpolation[]) for creating this collection.
float	distance	The curve-relative distance to convert to an interpolation ratio (also referred to as 't').

Returns

Type	Description
float	The normalized interpolation ratio associated to distance on the designated curve.

Type Parameters

Name	Description
T	The collection type.

GetNearestPoint(BezierCurve, Ray, int)

Gets the point on a BezierCurve nearest to a ray.

Declaration

public static float3 GetNearestPoint(BezierCurve curve, Ray ray, int resolution = 16)

Parameters

Type	Name	Description
BezierCurve	curve	The BezierCurve to compare.
Ray	ray	The input ray.
int	resolution	The number of line segments on this curve that are rasterized when testing for the nearest point. A higher value is more accurate, but slower to calculate.

Returns

Type	Description
float3	Returns the nearest position on the curve to a ray.

GetNearestPoint(BezierCurve, Ray, out float3, out float, int)

Gets the point on a BezierCurve nearest to a ray.

Declaration

public static float GetNearestPoint(BezierCurve curve, Ray ray, out float3 position, out float interpolation, int resolution = 16)

Parameters

Type	Name	Description
BezierCurve	curve	The BezierCurve to compare.
Ray	ray	The input ray.
float3	position	The nearest position on the curve to a ray.
float	interpolation	The ratio from range 0 to 1 along the curve at which the nearest point is located.
int	resolution	The number of line segments that this curve will be rasterized to when testing for nearest point. A higher value will be more accurate, but slower to calculate.

Returns

Type	Description
float	The distance from ray to nearest point on a BezierCurve.

Split(BezierCurve, float, out BezierCurve, out BezierCurve)

Decompose a curve into two smaller curves matching the source curve.

Declaration

public static void Split(BezierCurve curve, float t, out BezierCurve left, out BezierCurve right)

Parameters

Type	Name	Description
BezierCurve	curve	The source curve.
float	t	A mid-point on the source curve defining where the two smaller curves control points meet.
BezierCurve	left	A curve from the source curve first control point to the mid-point, matching the curvature of the source curve.
BezierCurve	right	A curve from the mid-point to the source curve fourth control point, matching the curvature of the source curve.