how to add trees to terrain based on texture

Hi everyone, i finished making a script to generate a terrain from libNoise, auto texture with another script to add textures based on height and slope, and one for grass generation.



I'v been trying to add trees to my terrain based on the texture on the ground, but don't know what i have to use for this...

If anyone already did something similar, it would be great if you can help!

 

Once you have your list of possible tree sites (am not going to assume how you do that), you can query the terrainData splatmapData for the index of the dominant texture at each tree position. Here is a link to a script I wrote for that. dorpeleg has also given a C# conversion in the comments : http://answers.unity3d.com/questions/456973/getting-the-texture-of-a-certain-point-on-terrain.html
Interestingly enough, I've been making some tools to do the same thing you have here!

 

Thanks for the reply, oh and those tutorials you did a while back for the libnoise helped a lot!
Cool, what exactly can your tools do?

 

Can't get the trees placed on the specific splat texture which is the 2nd texture of 3...

Could you give an example of random placement on only that texture?
Any help is appreciated thanks!

Using this to place objects and trees randomly... but cant get the objects placed on the areas with specific splat textures..

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3. public class RandomObjects : MonoBehaviour
4. {
5.     public Terrain terrain;
6.     public int numberOfObjects; // number of objects to place
7.     private int currentObjects; // number of placed objects
8.     public GameObject objectToPlace; // GameObject to place
9.     private int terrainWidth; // terrain size (x)
10.     private int terrainLength; // terrain size (z)
11.     private int terrainPosX; // terrain position x
12.     private int terrainPosZ; // terrain position z
13.     void Start()
14.     {
15.         terrain = gameObject.GetComponent<Terrain> ();
16.         // terrain size x
17.         terrainWidth = (int)terrain.terrainData.size.x;
18.         // terrain size z
19.         terrainLength = (int)terrain.terrainData.size.z;
20.         // terrain x position
21.         terrainPosX = (int)terrain.transform.position.x;
22.         // terrain z position
23.         terrainPosZ = (int)terrain.transform.position.z;
24.  
25.         for (int t =0; t <50; t++){
26.  
27.             if(currentObjects <= numberOfObjects)
28.             {
29.                 // generate random x position
30.                 int posx = Random.Range(terrainPosX, terrainPosX + terrainWidth);
31.                 // generate random z position
32.                 int posz = Random.Range(terrainPosZ, terrainPosZ + terrainLength);
33.                 // get the terrain height at the random position
34.                 float posy = Terrain.activeTerrain.SampleHeight(new Vector3(posx, 0, posz));
35.                 // create new gameObject on random position
36.                 GameObject newObject = (GameObject)Instantiate(objectToPlace, new Vector3(posx, posy, posz), Quaternion.identity);
37.                 currentObjects += 1;
38.             }
39.             if(currentObjects == numberOfObjects)
40.             {
41.                 Debug.Log("Generate objects complete!");
42.             }
43.         }
44.  
45.     }
46.     // Update is called once per frame
47.     void Update()
48.     {
49.         // generate objects
50.  
51.     }
52. }

 

Couple of observations:
The for-loop with a hard-coded value. This should use numberOfObjects instead of 50.
Although the variables currentObjects and numberOfObjects could be used in a while-loop, checking if the random site is feasible and if there is no tree assigned there already:

Code (csharp):

1. while( currentObjects < numberOfObjects )
2. {
3.    // get random site
4.    // if site is feasible(texture index and slope angle), and site has no tree already, add tree and currentObjects++;
5. }
6. Debug.Log("Generate objects complete!");

line 34: using Terrain.activeTerrain, but you already have a reference to the terrain on line 15

Code (csharp):

1. float posy = terrain.SampleHeight(new Vector3(posx, 0, posz));

Regarding checking the random tree position terrain texture index:
As you are using world-space coordinates for tree position, simply pass that to the GetMainTexture function

Code (csharp):

1. int terrainTextureIndexToPlaceTreeOn = 1; // specific splat texture which is the 2nd texture of 3...
2. Vector3 randomTreePos = new Vector3( posx, posy, posz );
3. int textureIndexAtRandomTreePos = GetMainTexture( randomTreePos );
4.  
5. if ( textureIndexAtRandomTreePos == terrainTextureIndexToPlaceTreeOn )
6. {
7.    // should also check if there is not a tree there already
8.    Add Tree Object
9.    currentObjects++;
10. }

Personally I think for you a better approach would be to: create a list of all possible tree sites; then choose random values from that list to place trees

Code (csharp):

1. // create a list of all possible sites
2. List< Vector3 > possibleTreeSites = new List< Vector3 >();
3. // using your method of integers within the terrain width and length
4. for ( int x = 0; x < terrainWidth; x++ )
5. {
6.    for ( int z = 0; z < terrainLength; z++ )
7.    {
8.      Vector3 checkPos = new Vector3( terrainPosX + x, 0, terrainPosZ + z );
9.      int textureIndexAtCheckPos = GetMainTexture( checkPos );
10.      // consider also checking the slope angle
11.  
12.      if ( textureIndexAtCheckPos == terrainTextureIndexToPlaceTreeOn )
13.      {
14.        possibleTreeSites.Add( checkPos );
15.      }
16.    }
17. }
18.  
19. // now you have a list of all possible sites, draw 50(numberOfObjects) values from that list to place a tree
20.  
21. // first check there are enough positions in the list
22. if ( numberOfObjects > possibleTreeSites.Count )
23. {
24.    numberOfObjects = possibleTreeSites.Count;
25. }
26.  
27. // now loop, draw random values and place tree
28. for ( int t = 0; t < numberOfObjects; t++ )
29. {
30.    // get random index of possibleTreeSites
31.    int randomIndex = Random.Range( 0, possibleTreeSites.Count );
32.  
33.    // get Y-value for position
34.    Vector3 treeSite = possibleTreeSites[ randomIndex ]; // <- EDIT: fixed incorrect brackets
35.    float posY = terrain.SampleHeight( treeSite );
36.    treeSite.y = posY;
37.  
38.    // place tree
39.    GameObject newObject = (GameObject)Instantiate(objectToPlace, treeSite, Quaternion.identity);
40.  
41.    // remove that site from the list!!
42.    possibleTreeSites.RemoveAt( randomIndex );
43. }

Please note this code is just a pseudo-example so you don't repeat random sites.

Regarding your query about my terrain tools:

Spoiler

Currently working on:

Copy Terrain : select resolution; heightmap; textures; splatmap; details; detailmap; trees; treedata
Paint By Slope Angles : currently only for exactly 4 textures
Mass Place Trees : select count; slope angle; water level(no underwater trees)
Grass Around Trees : places grass around trees. select radius; slope angle; density; density falloff
Grass On Texture : density based on slope angle using curves

Still need to clean up some stuff, then make videos showing how they work. Shall post the link when complete

 

Thanks will try this code when i get home!
Nice, all the features i'v been trying to make for a terrainGen script..
You going to put it on the asset store?

 

=
error CS0119: Expression denotes a `variable', where a `method group' was expected
Not sure what to make of this...

 

That's a typo, sorry. I wrote the pseudocode in notepad++, so untested.

Code (csharp):

1. Vector3 treeSite = possibleTreeSites[ randomIndex ];

Accessing an array(well, a list, a type of collection), not a function. Note the square brackets.
I have fixed the other post.

Edit: I hope you see what is happening in that example.
A list of all possible tree sites is made.
Then a loop for the desired number of trees, where a random position in that list is selected.
That line is getting a value from that random position in the list.

Not going to put my stuff on the asset store, it'll be free on my 'site (maybe I'll publish here too).

 

You Sir... are a Genius!!

Already fixed slope and water issue in another script will just add them together later....
But the texture spawn issue is 100% Gone!


THANKS a lot!

 

What is your website address?

 

Hey man, I need your help. I am not a scripting guy, just a simple level designer. I am learning some world designing skills. Do you have this script working? Does it place specific tree on specific texture? I exactly need that thing, but cannot find anywhere else. So please, could you give me the working script? I'll be really thankful!

 

Could you please show us how you achieve grass generation? It would be so helpful for me. Thanks!