using UnityEngine;
using System.Collections;

public class ProceduralPlane : MonoBehaviour {

    public float h = 2.0f;
    public float w = 2.0f;

    public int l = 3;

    public Mesh m;
    // Use this for initialization
    void Start () {
        m = new Mesh();
        m.vertices = new Vector3[]
        {
            -transform.right*w, //left
            transform.right*w, //right

            -transform.right*w + transform.forward*h, //top left
            transform.right*w + transform.forward*h, //top right
        };
        m.triangles = new int[]
        {
            0,2,1,1,2,3
        };
        m.RecalculateNormals();
        GetComponent<MeshFilter>().mesh = m;

        for (int i = 0; i < l; i++)
            AddQuad();
    }

    void AddQuad()
    {
        int vindex = m.vertices.Length-1;
        int tindex = m.triangles.Length-1;

        //Debug.Log(vindex+"="+m.vertices[vindex]);

        Vector3[] new_vertices = new Vector3[m.vertices.Length+2];
        int[] new_triangles = new int[m.triangles.Length+6];

        m.vertices.CopyTo(new_vertices,0);
        m.triangles.CopyTo(new_triangles,0);

        new_vertices[vindex+1] = m.vertices[vindex-1]+transform.forward*h;
        new_vertices[vindex+2] = m.vertices[vindex]+transform.forward*h;

        new_triangles[tindex+1] = m.triangles[tindex-1];
        new_triangles[tindex+2] = m.triangles[tindex]+1;
        new_triangles[tindex+3] = m.triangles[tindex];

        new_triangles[tindex+4] = m.triangles[tindex];
        new_triangles[tindex+5] = m.triangles[tindex]+1;
        new_triangles[tindex+6] = m.triangles[tindex]+2;

        //Debug.Log(tindex+6+" triangle = "+(m.triangles[tindex]+2).ToString() );
        //Debug.Log(tindex+6+" vertex = "+new_vertices[m.triangles[tindex]+2] );

        string t = "";
        foreach(int i in new_triangles)
            t += " "+i.ToString();
        Debug.Log(t);

        t = "";
        foreach(Vector3 v in new_vertices)
            t += " "+v.ToString();
        Debug.Log(t);

        m.vertices = new_vertices;
        m.triangles = new_triangles;

        m.RecalculateNormals();

        /*Vector3[] normals = m.normals;
        int x;
        for (x = 0; x < normals.Length; x++)
            normals[x] = Vector3.up;
        m.normals = normals;
        */

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

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

    }
}