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CurveTangent Enumeration

  • Article

Specifies different tangent types to be calculated for CurveKey points in a Curve.

Namespace: Microsoft.Xna.Framework
Assembly: Microsoft.Xna.Framework (in microsoft.xna.framework.dll)

Syntax

public enum CurveTangent

Members

  Member name Description
Flat A Flat tangent always has a value equal to zero.
Linear

A Linear tangent at a CurveKey is equal to the difference between its Value and the Value of the preceding or succeeding CurveKey.

For example, in Curve MyCurve, where i is greater than zero and (i + 1) is less than the total number of CurveKeys in MyCurve, the linear TangentIn of MyCurve.Keys[i] is equal to:

  ( MyCurve.Keys[i].Value - MyCurve.Keys[i - 1].Value )

Similarly, the linear TangentOut is equal to:

  ( MyCurve.Keys[i + 1].Value - MyCurve.Keys[i].Value.)
Smooth

A Smooth tangent smooths the inflection between a TangentIn and TangentOut by taking into account the values of both neighbors of the CurveKey.

The smooth TangentIn of MyCurve.Keys[i] is equal to:

  ( ( MyCurve.Keys[i + 1].Value - MyCurve.Keys[i - 1].Value ) * 
    ( ( MyCurve.Keys[i].Position - MyCurve.Keys[i - 1].Position ) /
      ( MyCurve.Keys[i + 1].Position - MyCurve.Keys[i-1].Position ) ) )

Similarly, the smooth TangentOut is equal to:

  ( ( MyCurve.Keys[i + 1].Value - MyCurve.Keys[i - 1].Value ) *
    ( ( MyCurve.Keys[i + 1].Position - MyCurve.Keys[i].Position ) /
      ( MyCurve.Keys[i + 1].Position - MyCurve.Keys[i - 1].Position ) ) )

See Also

Reference

Microsoft.Xna.Framework Namespace

Platforms

Xbox 360, Windows 7, Windows Vista, Windows XP, Windows Phone