Error on script for detecting the terrain texture

Questions & Answers
1

Hey everyone.
I’m new to Unity an I’m having problems with this script for detecting the terrain texture under the player.
I’'m using the script that I’ve found here:

When I run the game I get error:
T
exture rectangle is out of bounds (824 + 1 > 512)
UnityEngine.TerrainData:GetAlphamaps(Int32, Int32, Int32, Int32)

(From what I can tell the 824 is the posZ and the 512 is one of the map dimensions.)
the error is on this line:
float[,] aMap = t.terrainData.GetAlphamaps(posX, posZ, 1, 1);
the script looks like this:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CheckTerrainTexture : MonoBehaviour
{

    public Transform playerTransform;
    public Terrain t;
    public float mapx = 0;
    public float mapy = 0;
    public int posX;
    public int posZ;
    public float[] textureValues;

    void Start()
    {
        t = Terrain.activeTerrain;
        playerTransform = gameObject.transform;
    }

    void Update()
    {
        // For better performance, move this out of update 
        // and only call it when you need a footstep.
        GetTerrainTexture();
     mapx= t.terrainData.alphamapWidth;
     mapy= t.terrainData.alphamapHeight;
    }

    public void GetTerrainTexture()
    {
        ConvertPosition();
        CheckTexture();
    }

    void ConvertPosition()
    {
        Vector3 terrainPosition = playerTransform.position - t.transform.position;

        Vector3 mapPosition = new Vector3
        (terrainPosition.x / t.terrainData.size.x, 0,
        terrainPosition.z / t.terrainData.size.z);

        float xCoord = mapPosition.x * t.terrainData.alphamapWidth;
        float zCoord = mapPosition.z * t.terrainData.alphamapHeight;

        posX = (int)xCoord;
        posZ = (int)zCoord;
    }

    void CheckTexture()
    {
        float[,,] aMap = t.terrainData.GetAlphamaps(posX, posZ, 1, 1);
        textureValues[0] = aMap[0, 0, 0];
        textureValues[1] = aMap[0, 0, 1];
        textureValues[2] = aMap[0, 0, 2];
        textureValues[3] = aMap[0, 0, 3];
    }
}

Can someone please help me fix this problem?

2

Heres my code, i fixed it, the problem you have is that you are not on the terrain, therefore it cant see any terrain texture below you, heres my code i have fixed the issues and added sounds :

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CheckTerrainTexture : MonoBehaviour {

public Transform playerTransform;
public Terrain t;

public int posX;
public int posZ;
public float[] textureValues;

public AudioSource source;

public AudioClip[] stoneClips;
public AudioClip[] dirtClips;
public AudioClip[] sandClips;
public AudioClip[] grassClips;

AudioClip previousClip;

void Start () 
  {
    t = Terrain.activeTerrain;
    playerTransform = gameObject.transform;
  }

void Update()
  {
    // For better performance, move this out of update 
    // and only call it when you need a footstep.
    GetTerrainTexture();
  }

public void GetTerrainTexture()
  {
    ConvertPosition(playerTransform.position);
    CheckTexture();
  }

void ConvertPosition(Vector3 playerPosition)
  {
    Vector3 terrainPosition = playerPosition - t.transform.position;

    Vector3 mapPosition = new Vector3
    (terrainPosition.x / t.terrainData.size.x, 0,
    terrainPosition.z / t.terrainData.size.z);

    float xCoord = mapPosition.x * t.terrainData.alphamapWidth;
    float zCoord = mapPosition.z * t.terrainData.alphamapHeight;

    posX = (int)xCoord;
    posZ = (int)zCoord;
  }

void CheckTexture()
  {
    float[,,] aMap = t.terrainData.GetAlphamaps (posX, posZ, 1, 1);
    textureValues[0] = aMap[0,0,0];
    textureValues[1] = aMap[0,0,1];
    textureValues[2] = aMap[0,0,2];
    textureValues[3] = aMap[0,0,3];
  }
  public void PlayFootstep()
{   
  GetTerrainTexture();

  if (textureValues[0] > 0)
  {
    source.PlayOneShot(GetClip(stoneClips), textureValues[0]);
  }
  if (textureValues[1] > 0)
  {
    source.PlayOneShot(GetClip(dirtClips), textureValues[1]);
  }
  if (textureValues[2] > 0)
  {
    source.PlayOneShot(GetClip(dirtClips), textureValues[2]);
  }
  if (textureValues[3] > 0)
  {
    source.PlayOneShot(GetClip(dirtClips), textureValues[3]);
  }
}

AudioClip GetClip(AudioClip[] clipArray)
  {
    int attempts = 3;
    AudioClip selectedClip = 
    clipArray[Random.Range(0, clipArray.Length - 1)];

    while (selectedClip == previousClip && attempts > 0)
      {
        selectedClip = 
        clipArray[Random.Range(0, clipArray.Length - 1)];
        
        attempts--;
      }

    previousClip = selectedClip;
    return selectedClip;

  }
}
3

Thank you very much!
It works :slight_smile: