How do i assign perlin noise

Question

I am trying to make a procedural map using perlin noise. I have made a script that generates a plane mesh, and now i want to use mathf.perlinnoise to create hills. But i cannot figure out how to implement it.

My plane generation script was made with the help of quill18's tile map tutorial.

 using UnityEngine;
 using System.Collections;
 
 [ExecuteInEditMode]
 [RequireComponent(typeof(MeshFilter))]
 [RequireComponent(typeof(MeshRenderer))]
 [RequireComponent(typeof(MeshCollider))]
 
 public class TileMap2 : MonoBehaviour {
 
     public int size_x = 100;
     public int size_z = 50;
     public float tileSize = 1.0f;
     
     
 
     // Use this for initialization
     void Start () {
     
         BuildMesh();
     
     }
     
 
     public void BuildMesh () {
     
         int numTiles = size_x * size_z;
         int numTris = numTiles * 2;
     
         int vsize_x = size_x +1;
         int vsize_z = size_z +1;
         int numVerts = vsize_x * vsize_z;
         
         float noise = 0.1f;
 
     
         // generate the mesh data
         Vector3[] vertices = new Vector3[numVerts];
         Vector3[] normals = new Vector3[numVerts];
         Vector2[] uv = new Vector2[numVerts];
         
         int[] triangles = new int[ numTris * 3 ];
     
         int x, z;    

             //my perlin noise nonsense..???

         var noiseOffset = new Vector2(Random.Range(0f, 100f), Random.Range(0f, 100f));
         
         for(z=0; z < size_z; z++) {
             for(x=0; x < size_x; x++) {
                 
                 var a = z * vsize_x + x + noiseOffset.x;
                 var b = z * vsize_x + x + noiseOffset.y;
                 noise = Mathf.PerlinNoise(a, b);
                 
                 
             }
         }
 
                 
     
         for(x=0; x < vsize_x; x++) {
             for(z=0; z < vsize_z; z++) {
                             
                 vertices[ z * vsize_x + x ] = new Vector3( x*tileSize, noise, z*tileSize );
                 normals[ z * vsize_x + x ] = Vector3.up;
                 uv[ z * vsize_x + x ] = new Vector2( (float)x / size_x, (float)z / size_z );
             }
         }
         
         for(z=0; z < size_z; z++) {
             for(x=0; x < size_x; x++) {
                 int squareIndex = z * size_x + x;
                 int triOffset = squareIndex * 6;
                 triangles[triOffset + 0] = z * vsize_x + x +            0;
                 triangles[triOffset + 2] = z * vsize_x + x + vsize_x + 1;
                 triangles[triOffset + 1] = z * vsize_x + x + vsize_x + 0;
                 
                 triangles[triOffset + 3] = z * vsize_x + x +            0;
                 triangles[triOffset + 5] = z * vsize_x + x +            1;
                 triangles[triOffset + 4] = z * vsize_x + x + vsize_x + 1;
         
             }
         }
         
 
                     
         // create new mesh and populate with the data
         Mesh mesh = new Mesh();
         mesh.vertices = vertices;
         mesh.triangles = triangles;
         mesh.normals = normals;
         mesh.uv = uv;
         
         // assign our mesh to our filter/renderer
         MeshFilter mesh_filter = GetComponent<MeshFilter>();
         MeshRenderer mesh_renderer = GetComponent<MeshRenderer>();
         MeshCollider mesh_collider = GetComponent<MeshCollider>();
         
         mesh_filter.mesh = mesh;
         mesh_collider.sharedMesh = mesh;
         
     }
 }

When i run the script now, it sets the entire plane at a random height. If i run the perlin noise stuff in the for loop making the mesh, it just becomes noise (or if i dont use random.range, nothing). I understand i have to change the y axis of Vertecies. But how do i implement the smooth perlin noise? I am still learning, especially c#..

Answer 1

Answer by maccabbe · Jun 15, 2015 at 03:19 PM

In lines 50-59 you are generating perlin noise for each point but only storing the last value. So when you assign the positions of the verticies in lines 63-70 you use the last generated height for all verticies. You would either have to store the generated heights or use each one immediately. i.e. replace lines 50-70 with

 for(x=0; x < vsize_x; x++) {
     for(z=0; z < vsize_z; z++) {                 
         var a = z * vsize_x + x + noiseOffset.x;
         var b = z * vsize_x + x + noiseOffset.y;
         noise = Mathf.PerlinNoise(a, b);
                              
         vertices[ z * vsize_x + x ] = new Vector3( x*tileSize, noise, z*tileSize );
         normals[ z * vsize_x + x ] = Vector3.up;
         uv[ z * vsize_x + x ] = new Vector2( (float)x / size_x, (float)z / size_z );
     }
 }

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Answer 2

Thank you.. after messing with it for a while i came up with this:

         var noiseOffset = new Vector2(Random.Range(0f, 10f), Random.Range(0f, 10f));
     
         for(x=0; x < vsize_x; x++) {
             for(z=0; z < vsize_z; z++) {
                 
                 var a = x + size_x * 2f + noiseOffset.x;
                 var b = z + size_x * 2f + noiseOffset.y;            
                 
                 float noise = Mathf.PerlinNoise(a / 10, b / 10);
                 
                             
                 vertices[ z * vsize_x + x ] = new Vector3( x*tileSize, noise * 10, z*tileSize );
                 
                 normals[ z * vsize_x + x ] = Vector3.up;
                 
                 uv[ z * vsize_x + x ] = new Vector2( (float)x / size_x, (float)z / size_z );
             }
         }

Any suggestions to how i can mix 2 or more x perlin noise to get a more natural terrain?

How do i assign perlin noise

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