TerrainData.GetAlphamaps

Parameters

Returns

float[,,] A 3D array of floats, where the 3rd dimension represents the mixing weight of each splatmap at each x,y coordinate.

Description

Returns the alpha map at a position x, y given a width and height.

The returned array is three-dimensional - the first two dimensions represent x and y coordinates on the map, while the third denotes the splatmap texture to which the alphamap is applied.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    // Add some random "noise" to the alphamaps.
    void AddAlphaNoise(Terrain t, float noiseScale)
    {
        float[,,] maps = t.terrainData.GetAlphamaps(0, 0, t.terrainData.alphamapWidth, t.terrainData.alphamapHeight);

        for (int y = 0; y < t.terrainData.alphamapHeight; y++)
        {
            for (int x = 0; x < t.terrainData.alphamapWidth; x++)
            {
                float a0 = maps[x, y, 0];
                float a1 = maps[x, y, 1];

                a0 += Random.value * noiseScale;
                a1 += Random.value * noiseScale;

                float total = a0 + a1;

                maps[x, y, 0] = a0 / total;
                maps[x, y, 1] = a1 / total;
            }
        }

        t.terrainData.SetAlphamaps(0, 0, maps);
    }
}