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

public class NoiseDisplay : MonoBehaviour
{
    public int resolution = 512;
    public float zoom = 100f;

    public Color oceanColor = Color.cyan;
    public float seaLevel = 0.5f;
    public float oceanZoom = 3.0f;

    FastNoise noise = new FastNoise();

    public void Start()
    {
        noise.SetNoiseType(FastNoise.NoiseType.SimplexFractal);
        noise.SetFractalOctaves(6);
    }

    public float[,] GenerateNoise()
    {
        float[,] values = new float[resolution, resolution];

        for (int x = 0; x < resolution; x++) {
        for (int y = 0; y < resolution; y++) {

            float val = sample(x, y, zoom);

            values[x, y] = val;

        }}

        return values;
    }

    public float sample(int x, int y, float zoom)
    {
        return RangeToRange( noise.GetNoise(x / zoom, y / zoom), -1f, 1f, 0f, 1f);
    }














    public float RangeToRange(float _input, float _low, float _high, float _newLow, float _newHigh)
    {
        return ((_input - _low) / (_high - _low)) * (_newHigh - _newLow) + _newLow;
    }

    public bool update = false;
    public Texture2D texture;

    public void Update()
    {
        if (update)
        {
            Render( GenerateNoise() );
            update = false;
        }
    }

    public void Render(float[,] values)
    {
        int width = resolution, height = resolution;

        Texture2D tex = new Texture2D(width, height);

        Color[] colors = new Color[width * height];

        for (int x = 0; x < height; x++)
        {
            for (int y = 0; y < width; y++)
            {
                Color color = Color.Lerp(Color.black, Color.white, values[x, y]);

                if (values[x, y] < seaLevel)
                {
                    color *= oceanColor;
                }

                colors[toIndex(x, y)] = color;
            }
        }

        tex.SetPixels(colors);
        tex.Apply();

        texture = tex;
    }

    public int toIndex(int _x, int _y)
    {
        if (_x < 0) _x = 0;
        if (_y < 0) _y = 0;
        if (_x >= resolution) _x = resolution - 1;
        if (_y >= resolution) _y = resolution - 1;

        return (_y * resolution) + _x;
    }

    private void OnGUI()
    {
        if (Event.current.type.Equals(EventType.Repaint))
        {
            if (texture != null) Graphics.DrawTexture(new Rect(0, 0, resolution, resolution), texture);
        }
    }
}