In Unity3D, I am following a tilemap tutorial. However, the UV layout is coming out strange. How can I fix this?

Question

I'm following this tutorial set: https://www.youtube.com/watch?v=owBt9SNKXCI&index=6&list=PLbghT7MmckI4qGA0Wm_TZS8LVrqS47I9R to dynamically build a tile map layout. It works to a point, but it generates a very strange layout with 128 x 128 sized tiles.

Clearly that strange partitioning shouldn't be happening, but I cannot seem to track down what's going on to cause it. Here is my version of the code, which is mostly identical to quill18creates's version sans a few small differences:

using UnityEngine;
using System.Collections;

[ExecuteInEditMode]
public class TileMap : MonoBehaviour {

    public int size_x = 100;
    public int size_z = 50;
    public float tileSize = 1.0f;

    public Texture2D terrainTiles;
    int tileResolution = 128;

    // Use this for initialization
    void Start () {
        BuildMesh();
    }

    Color[][] ChopUpTiles() {
        int numTilesPerRow = terrainTiles.width / tileResolution;
        int numRows = terrainTiles.height / tileResolution;

        Color[][] tiles = new Color[numTilesPerRow*numRows][];

        for(int y=0; y < numRows; y++) {
            for(int x=0; x < numTilesPerRow; x++) {
                tiles[y * numTilesPerRow + x] = terrainTiles.GetPixels( x*tileResolution , y*tileResolution, tileResolution, tileResolution );
            }
        }

        return tiles;
    }

    void BuildTexture() {
        //DTileMap map = new DTileMap(size_x, size_z);

        int texWidth = size_x * tileResolution;
        int texHeight = size_z * tileResolution;
        Texture2D texture = new Texture2D(texWidth, texHeight);

        Color[][] tiles = ChopUpTiles();


        for(int y=0; y < size_z; y++) {
            for(int x=0; x < size_x; x++) {
                Color[] p = tiles[Mathf.RoundToInt(Random.Range(0, 5))];
                texture.SetPixels(x * tileResolution, y * tileResolution, tileResolution, tileResolution, p);
            }
        }

        //texture.filterMode = FilterMode.Bilinear;
        texture.wrapMode = TextureWrapMode.Clamp;
        texture.Apply();

        MeshRenderer mesh_renderer = GetComponent<MeshRenderer>();
        mesh_renderer.sharedMaterials[0].mainTexture = texture;
    }

    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;

        // 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;
        for(z=0; z < vsize_z; z++) {
            for(x=0; x < vsize_x; x++) {
                vertices[ z * vsize_x + x ] = new Vector3( x*tileSize, 0, -z*tileSize );
                normals[ z * vsize_x + x ] = Vector3.up;
                uv[ (z * vsize_x) + x ] = new Vector2( (float)x / size_x, (float)z / size_z );
            }
        }
        Debug.Log ("Done Verts!");

        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 + 0;
                triangles[triOffset + 1] = z * vsize_x + x + vsize_x + 1;

                triangles[triOffset + 3] = z * vsize_x + x +           0;
                triangles[triOffset + 5] = z * vsize_x + x + vsize_x + 1;
                triangles[triOffset + 4] = z * vsize_x + x +           1;
            }
        }

        // Create a 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/collider
        MeshFilter mesh_filter = GetComponent<MeshFilter>();
        MeshCollider mesh_collider = GetComponent<MeshCollider>();

        mesh_filter.mesh = mesh;
        mesh_collider.sharedMesh = mesh;


        BuildTexture();
    }   
}

Answer 1

I don't get exactly what part is wrong in the image but I think it is that the same tiles are lumping together. I tried your code and it works well for me. But I guess the following part could be causing the lumping together problem for you:

Color[] p = tiles[Mathf.RoundToInt(Random.Range(0, 5))];

Instead you should do:

Color[] p = tiles[Random.Range(0, 5)];

Because, the other way, Random is generating float numbers and maybe they are near the each other that rounding them to the integer gives same tile. Give it a try. Also just reminding, make sure the width and the height of your texture is divisible by 128.