add code

diamond_square_landscape/Assets/Scripts/DiamondSquare.cs

+
+using System;
+
+using UnityEngine;
+using Random = UnityEngine.Random;
+
+public class DiamondSquare : MonoBehaviour
+{
+    public int divisions; // number of faces
+    public float height;
+    public float size;
+    
+    private Vector3[] _verts; //array of all vertex
+    private int _vertCount; // count of vertex
+
+    private Vector2[] _uvs; // count of UVs
+    private int[] _triangles; // array of all triangles
+    
+    private Mesh mesh;
+    
+    
+
+    // Start is called before the first frame update
+    void Start()
+    {
+        mesh = new Mesh();
+        MeshFilter filter = gameObject.GetComponent<MeshFilter>();
+        if(!filter) gameObject.AddComponent<MeshFilter>();
+        GetComponent<MeshFilter>().mesh = mesh;
+        create_terrain();
+    }
+
+
+    void  create_terrain()
+    {
+        _vertCount = (int)Math.Pow(divisions + 1, 2); // number of vertices is 2^n + 1 
+        _verts = new Vector3[_vertCount]; // initiate the verts
+        _uvs = new Vector2[_vertCount]; // initiate the UVs
+        _triangles = new int [(int)Math.Pow(divisions, 2) * 6]; // numbers of triangles
+        // in the start is 2 * division^2
+        // in unity triangles are defined by 3 numbers 
+        // so result is 3 * 2 * division^2
+
+
+        //_____create the mesh______________________________________________________________________
+        int inx = 0;
+        for (int  offset = 0, x = 0; x <= divisions; x++)
+        {
+            for (int z = 0; z <= divisions; z++)
+            {
+                _verts[inx] = new Vector3(-0.5f*size+z*divisions, 0, 0.5f*size - x*divisions);
+                _uvs[inx] = new Vector2((float)x / divisions, (float)z / divisions); 
+                if (x<divisions && z <divisions)  create_triangles(inx, ref offset);
+                inx++;
+               
+            }
+        }
+        
+       //_____base_vertices______________________________________________________________________
+       _verts[0].y = Random.Range(-height, height);
+       _verts[divisions].y = Random.Range(-height, height);
+       _verts[_verts.Length-1].y = Random.Range(-height, height);
+       _verts[_verts.Length-divisions-1].y = Random.Range(-height, height);
+
+       //_____diamond_square_algorithm______________________________________________________________________
+       int iterations = (int)Mathf.Log(divisions, 2);
+       int numSquares = 1;
+       int squareSize = divisions;
+       for (int i = 0; i < iterations; i++)
+       {
+           int row = 0;
+           for (int j = 0; j < numSquares; j++)
+           {
+               int col = 0;
+               for (int k = 0; k < numSquares; k++)
+               {
+                   diamond_square(row, col, squareSize, height);
+                   col += squareSize;
+               }
+               row += squareSize;
+               
+           }
+
+           numSquares *= 2;
+           squareSize /= 2;
+           height *= 0.5f;
+
+       }
+       
+       
+      
+    }
+    
+    void diamond_square(int row, int col, int size, float offset)
+    {
+        //_____diamond__________________________________________________________________
+        int halfSize = (int)(size * 0.5f);
+        int topLeft = row * (divisions + 1) + col;
+        int botLeft = (row + size) * (divisions + 1) + col;
+        int mid = (row + halfSize) * (divisions + 1) + col + halfSize;
+        _verts[mid].y = (_verts[topLeft].y + _verts[topLeft + size].y 
+                                           + _verts[botLeft].y 
+                                           + _verts[botLeft+size].y) * 0.25f 
+                                           + Random.Range(-offset, offset);
+        //_____squares__________________________________________________________________
+        _verts[topLeft + halfSize].y = (_verts[topLeft].y 
+                                        + _verts[topLeft + size].y 
+                                        + _verts[mid].y)/3
+                                        + Random.Range(-offset, offset);
+        
+        _verts[mid-halfSize].y = (_verts[topLeft].y 
+                                  + _verts[botLeft + size].y 
+                                  + _verts[mid].y)/3
+                                  + Random.Range(-offset, offset);
+        _verts[mid+halfSize].y =  (_verts[topLeft+size].y 
+                                    + _verts[botLeft + size].y 
+                                    + _verts[mid].y)/3
+                                   + Random.Range(-offset, offset);
+        _verts[botLeft+halfSize].y =  (_verts[botLeft].y 
+                                    + _verts[botLeft + size].y 
+                                    + _verts[mid].y)/3
+                                   + Random.Range(-offset, offset);
+    }
+    void create_triangles(int vert, ref int offset)
+    {
+        int top = vert;
+        int bottom = vert + divisions +1;
+       
+    _triangles[offset++] = top;
+    _triangles[offset++] = top +1;
+    _triangles[offset++] = bottom;
+    
+    _triangles[offset++] = bottom;
+    _triangles[offset++] = top +1;
+    _triangles[offset++] = bottom  + 1;
+  
+    }
+
+    // Update is called once per frame
+    private void Update()
+    {
+        update_terrain();
+    }
+
+    void update_terrain()
+    {
+        mesh.Clear();
+
+        mesh.vertices = _verts;
+        mesh.triangles = _triangles;
+        mesh.uv = _uvs;
+        
+        mesh.RecalculateNormals();
+        mesh.RecalculateBounds();
+    }
+    
+}