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

public class TimeSignal
{
    public float[] x;
    public float[] y;

    public TimeSignal(int N)
    {
        x = new float[N];
        y = new float[N];
    }
}

public class LineFFT : MonoBehaviour
{
    LineRenderer lr;
    TimeSignal signal = new TimeSignal(1000);
    void Start()
    {
        lr = GetComponent<LineRenderer>();

        for(int i = 0; i < 1000; i++)
        {
            //x-values
            signal.x[i] = Mathf.Lerp(0, 100, (float)i / 1000f);
            //y-values
            signal.y[i] = 2 * Mathf.Sin(1 * signal.x[i]) + 1* Mathf.Cos(2 * signal.x[i] + Mathf.PI/4.2f);
        }

        lr.SetPositions(DFT(signal, 3.0f));

    }

    // Update is called once per frame
    void Update()
    {
        lr.SetPositions(DFT(signal, Time.time * 0.25f));
    }

    Vector3[] DFT(TimeSignal X, float k)
    {
        int N = X.x.Length;

        Vector3[] c = new Vector3[N];

        for(int n = 0; n < N; n++)
        {
            c[n] = X.y[n] * new Vector3(
                 Mathf.Cos((2 * Mathf.PI) / N * k * n),
                -Mathf.Sin((2 * Mathf.PI) / N * k * n),
                0);
        }

        return c;
    }
}