siege-song/Data/Assets/Digger/Modules/AdvancedOperations/Splines/Bezier.cs

using UnityEngine;

namespace Digger.Modules.AdvancedOperations.Splines
{
    public static class Bezier
    {
        public static Vector3 GetPoint(Vector3 p0, Vector3 p1, Vector3 p2, float t)
        {
            t = Mathf.Clamp01(t);
            var oneMinusT = 1f - t;
            return
                oneMinusT * oneMinusT * p0 +
                2f * oneMinusT * t * p1 +
                t * t * p2;
        }

        public static Vector3 GetFirstDerivative(Vector3 p0, Vector3 p1, Vector3 p2, float t)
        {
            return
                2f * (1f - t) * (p1 - p0) +
                2f * t * (p2 - p1);
        }

        public static Vector3 GetPoint(Vector3 p0, Vector3 p1, Vector3 p2, Vector3 p3, float t)
        {
            t = Mathf.Clamp01(t);
            var oneMinusT = 1f - t;
            return
                oneMinusT * oneMinusT * oneMinusT * p0 +
                3f * oneMinusT * oneMinusT * t * p1 +
                3f * oneMinusT * t * t * p2 +
                t * t * t * p3;
        }

        public static Vector3 GetFirstDerivative(Vector3 p0, Vector3 p1, Vector3 p2, Vector3 p3, float t)
        {
            t = Mathf.Clamp01(t);
            var oneMinusT = 1f - t;
            return
                3f * oneMinusT * oneMinusT * (p1 - p0) +
                6f * oneMinusT * t * (p2 - p1) +
                3f * t * t * (p3 - p2);
        }
    }
}