using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Spline : MonoBehaviour
{
    Mesh mesh;

    public int minX;
    public int maxX;

    public List<float> factors;
    // Start is called before the first frame update
    void Start()
    {
        mesh = new Mesh
        {
            name = "Spline"
        };
        factors = new List<float>();
        factors.Add(1);
        factors.Add(0);
        factors.Add(1);
    }

    // Update is called once per frame
    void Update()
    {
        
    }

    public void DrawSpline()
    {
        mesh.Clear();

        Vector3[] vectors = new Vector3[100 * (maxX - minX) + 1];
        int k = 0;
        float step = 0.01f;
        for (float i = minX; i <= maxX; i+=step)
        {
            float y = 0;
            for (int j = factors.Count - 1; j > 0; --j)
            {
                y += factors[j];
                y *= i;
            }
            y += factors[0];
            vectors[k] = new Vector3(i, y, 0);
            k++;
        }
        mesh.vertices = vectors;

        int[] triangle = new int[100 * (maxX - minX) * 2];
        for (int i = 0; i < vectors.Length - 1; ++i)
        {
            triangle[2 * i] = i;
            triangle[2 * i + 1] = i + 1;
        }

        mesh.SetIndices(triangle, MeshTopology.Lines, 0);

        GetComponent<MeshFilter>().mesh = mesh;
    }

}