Util.cs

using System;
using System.Numerics;

class Util
{
    public static Vector3 RotatePosition(Vector3 pos, Vector3 rot)
    {
        float x = pos.X;
        float y = pos.Y;
        float z = pos.Z;

        Vector3 result = new Vector3(pos.X, pos.Y, pos.Z);

        if (rot.Z != 0)
        {
            float cosZ = (float)Math.Cos(rot.Z);
            float sinZ = (float)Math.Sin(rot.Z);
            result.X = x * cosZ - y * sinZ;
            result.Y = y * cosZ + x * sinZ;
        }

        if (rot.X != 0)
        {
            float cosX = (float)Math.Cos(rot.X);
            float sinX = (float)Math.Sin(rot.X);
            result.Y = y * cosX - z * sinX;
            result.Z = z * cosX + y * sinX;
        }

        if (rot.Y != 0)
        {
            float cosY = (float)Math.Cos(rot.Y);
            float sinY = (float)Math.Sin(rot.Y);
            result.Z = z * cosY - x * sinY;
            result.X = x * cosY + z * sinY;
        }

        return result;
    }
}