Spline

CarFollowSpline.cs

using UnityEngine;

public class CarFollowSpline : MonoBehaviour
{
    public SplineST spline;
    public float speed = 0.2f;
    private float t = 0f;
    Vector3 initialPosition;
    Vector3 initialRotation;

    void OnEnable()
    {
        initialPosition = transform.position;
        initialRotation = transform.eulerAngles;
    }

    void Update()
    {
        if (spline == null) return;

        t += Time.deltaTime * speed;
        t = Mathf.Clamp01(t); // 0-1 arası kalsın

        Vector3 position = spline.GetPoint(t);
        Vector3 direction = spline.GetTangent(t);

        transform.position = position;
        transform.rotation = Quaternion.LookRotation(direction);
    }

    [ContextMenu("Reset t")]
    public void ResetT()
    {
        t = 0f;
        transform.position = initialPosition;
        transform.eulerAngles = initialRotation;
    }

    public void SetSpeed(float newSpeed)
    {
        speed = newSpeed;
    }
}

SplineST.cs

using UnityEngine;

public class SplineST : MonoBehaviour
{
    [Header("Spline Noktaları (Sıralı)")]
    public Transform[] controlPoints;

    public Vector3 GetPoint(float t)
    {
        int numSections = controlPoints.Length - 3;
        if (numSections < 1)
        {
            Debug.LogWarning("Spline için en az 4 nokta gerekir.");
            return Vector3.zero;
        }

        t = Mathf.Clamp01(t);
        float scaledT = t * numSections;
        int currPt = Mathf.FloorToInt(scaledT);
        currPt = Mathf.Clamp(currPt, 0, numSections - 1);

        float u = scaledT - currPt;

        Vector3 a = controlPoints[currPt].position;
        Vector3 b = controlPoints[currPt + 1].position;
        Vector3 c = controlPoints[currPt + 2].position;
        Vector3 d = controlPoints[currPt + 3].position;

        return 0.5f * (
            (-a + 3f * b - 3f * c + d) * (u * u * u)
            + (2f * a - 5f * b + 4f * c - d) * (u * u)
            + (-a + c) * u
            + 2f * b
        );
    }

    public Vector3 GetTangent(float t)
    {
        float delta = 0.001f;
        Vector3 p1 = GetPoint(t);
        Vector3 p2 = GetPoint(t + delta);
        return (p2 - p1).normalized;
    }

    private void OnDrawGizmos()
    {
        if (controlPoints == null || controlPoints.Length < 4) return;

        Gizmos.color = Color.green;
        Vector3 prevPoint = GetPoint(0);
        for (float t = 0; t <= 1f; t += 0.01f)
        {
            Vector3 point = GetPoint(t);
            Gizmos.DrawLine(prevPoint, point);
            prevPoint = point;
        }
    }
}