Adding self-constructed diamond-square algorithm to the GameObject->3D Object->Terrain

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class DiamondSquare : MonoBehaviour {
6.  
7.     public TerrainData TerrainData;
8.  
9.     Mesh m;
10.  
11.     // Length of the square
12.     public float length;
13.     // Num of vertices in one side
14.     public int vertNum;
15.     // Max height
16.     public float height;
17.  
18.     Vector3[] vertices;
19.  
20.     void Start () {
21.         m = GetComponent<MeshFilter>().mesh;
22.         CreateTerrian();
23.     }
24.    
25.     void CreateTerrian () {
26.  
27.         m.name = "Terrian";
28.  
29.         // Num of the phase
30.         int division = vertNum - 1;
31.  
32.         float halfLength = length / 2;
33.  
34.         // The length of the smallest square
35.         float singleLength = length / division;
36.  
37.         int vertCount = vertNum * vertNum;
38.  
39.         // All the vertices of the terrian
40.         vertices = new Vector3[vertCount];
41.  
42.         Vector2[] uvs = new Vector2[vertCount];
43.  
44.         // Index of all the triangles
45.         int[] triVertex = new int[vertNum * vertNum * 6];
46.         int triIndex = 0;
47.  
48.         for (int i = 0; i < vertNum; i++) {
49.             for (int j = 0; j < vertNum; j++) {
50.  
51.                 vertices[i * vertNum + j] = new Vector3(-halfLength + singleLength * j, 0, halfLength - singleLength * i);
52.                 uvs[i * vertNum + j] = new Vector2((float)i / division, (float)j / division);
53.  
54.                 if (i < division && j < division) {
55.                     int topLeft = i * vertNum + j;
56.                     int botLeft = (i + 1) * vertNum + j;
57.                     int topRight = i * vertNum + j + 1;
58.                     int botRight = (i + 1) * vertNum + j + 1;
59.  
60.                     // Topright tri
61.                     triVertex[triIndex++] = topLeft;
62.                     triVertex[triIndex++] = topRight;
63.                     triVertex[triIndex++] = botRight;
64.                     // Botleft tri
65.                     triVertex[triIndex++] = topLeft;
66.                     triVertex[triIndex++] = botRight;
67.                     triVertex[triIndex++] = botLeft;
68.                 }
69.             }
70.         }
71.  
72.         vertices[0].y = Random.Range(-height, height);
73.         vertices[division].y = Random.Range(-height, height);
74.         vertices[vertCount - 1].y = Random.Range(-height, height);
75.         vertices[vertCount - division - 1].y = Random.Range(-height, height);
76.            
77.         int iteration = (int)Mathf.Log(division, 2);
78.         int numSquare = 1;
79.         int squareSize = division;
80.  
81.         for (int i = 0; i < iteration; i++) {
82.             int row = 0;
83.             for (int j = 0; j < numSquare; j++) {
84.                 int column = 0;
85.                 for (int k = 0; k < numSquare; k++) {
86.                     diamondSquare(row, column, squareSize, height);
87.                     column += squareSize;
88.                 }
89.                 row += squareSize;
90.             }
91.             squareSize /= 2;
92.             numSquare *= 2;
93.             height *= 0.5f;
94.         }
95.  
96.         m.vertices = vertices;
97.         m.uv = uvs;
98.         m.triangles = triVertex;
99.         m.RecalculateBounds();
100.         m.RecalculateNormals();
101.     }
102.  
103.     void diamondSquare (int row, int column, int squareSize, float height) {
104.  
105.         int halfSize = squareSize / 2;
106.         int topLeft = row * vertNum + column;
107.         int topRight = topLeft + squareSize;
108.         int botLeft = topLeft + vertNum * squareSize;
109.         int botRight = botLeft + squareSize;
110.         int topMid = (topLeft + topRight) / 2;
111.         int botMid = (botLeft + botRight) / 2;
112.         int leftMid = (topLeft + botLeft) / 2;
113.         int rightMid = (topRight + botRight) / 2;
114.         int mid = (topLeft + botRight) / 2;
115.  
116.         vertices[mid].y = (vertices[topLeft].y + vertices[topRight].y + vertices[botLeft].y + vertices[botRight].y) * 0.25f + Random.Range(-height, height);
117.  
118.         vertices[topMid].y = (vertices[topLeft].y + vertices[topRight].y + vertices[mid].y) / 3 + Random.Range(-height, height);
119.         vertices[botMid].y = (vertices[botLeft].y + vertices[botRight].y + vertices[mid].y) / 3 + Random.Range(-height, height);
120.         vertices[leftMid].y = (vertices[topLeft].y + vertices[botLeft].y + vertices[mid].y) / 3 + Random.Range(-height, height);
121.         vertices[rightMid].y = (vertices[topRight].y + vertices[botRight].y + vertices[mid].y) / 3 + Random.Range(-height, height);
122.     }
123.    
124. }
125.  

This is my own diamond-square algorithm attached to a GameObject->EmptyGameObject

I just want to attach it with the Terrain type Object and make use of it. I have difficulty modify the code to suit the type Terrain given by unity. Could any one can help me with this?

 

The code itself basicly just create a empty squre-form area and randomly generate the moutrain like terrain. But for the Terrain type given by unity, the empty squre-form area is already a given. I just need to make use the function void diamondSquare (int row, int column, int squareSize, float height); But I don't know how to appply it.