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


[RequireComponent(typeof(MeshFilter),typeof(MeshRenderer))]
public class Grid : MonoBehaviour
{
    public int xScale;
    public int yScale;
    private Mesh mesh;

    private Vector3[] vertexBuffer;

    private void Awake()
    {
        StartCoroutine(Generator());
    }

    private IEnumerator Generator()
    {
        WaitForSeconds wait = new WaitForSeconds(0.05f);
        vertexBuffer = new Vector3[(xScale + 1) * (yScale + 1)];
        Vector2[] uv = new Vector2[vertexBuffer.Length];
        GetComponent<MeshFilter>().mesh = mesh = new Mesh();

        for (int i = 0, z = 0; z <= yScale; z++)
        {
            for (int x = 0; x <= xScale; x++, i++)
            {
                vertexBuffer[i] = new Vector3(x, Random.Range(0.0f,1.0f), z);
                uv[i] = new Vector2((float)x / (float)xScale, (float)z / (float)yScale);
                yield return wait;
            }
        }

        mesh.vertices = vertexBuffer;
        mesh.uv = uv;

        int[] tris = new int[xScale * yScale * 6];

        for (int ti = 0, vi = 0, y = 0; y < yScale; y++, vi++)
        {
            for (int x = 0; x < xScale; x++, ti += 6, vi++)
            {
                tris[ti] = vi;
                tris[ti + 1] = tris[ti + 4] = vi + xScale + 1;
                tris[ti + 2] = tris[ti + 3] = vi + 1;
                tris[ti + 5] = vi + xScale + 2;
            }
        }

        mesh.triangles = tris;
        mesh.RecalculateNormals();
    }

    private void OnDrawGizmos()
    {
        if (vertexBuffer == null)
        {
            return;
        }

        Gizmos.color = Color.black;
        for (int i = 0; i< vertexBuffer.Length;i++)
        {
            Gizmos.DrawSphere(vertexBuffer[i], 0.1f);
        }
    }
}