A Unity class that calculates a forward vector from the tangent of a point on a 'BGCurve' closest to a given point, used in my 2.5D Platformer Engine.

Platformer2Point5D_Path

using UnityEngine;
using BansheeGz.BGSpline.Curve;

[RequireComponent(typeof(BansheeGz.BGSpline.Curve.BGCurve))]
public class Platformer2Point5D_Path : MonoBehaviour {

    private BGCurve curve;
    private BGCurveBaseMath math;
    
  	void Start () {
        curve = GetComponent<BGCurve>();
        math = new BGCurveBaseMath(curve, new BGCurveBaseMath.Config(BGCurveBaseMath.Fields.PositionAndTangent));
  	}

    // This is the important method
    public Vector3 CalculateForwardFromClosestPoint(Vector3 outsidePoint, out Vector3 curvePoint)
    {
        Vector3 forward = CalculateTangentFromClosestPoint(outsidePoint, out curvePoint);
        forward.y = 0;
        return forward.normalized;
    }
    
    private Vector3 CalculateTangentFromClosestPoint(Vector3 outsidePoint, out Vector3 curvePoint)
    {
        float curvePointDistance;
        curvePoint = math.CalcPositionByClosestPoint(outsidePoint, out curvePointDistance);
        Vector3 tangent = math.CalcTangentByDistance(curvePointDistance);
        return tangent;
    }

}