Как сделать смарт материал? Unity3D

Используй этот скрипт на террейне и он позволит тебе использовать текстуры в зависимости от высоты. Источник: https://forum.unity.com/threads/adding-terrain-textures-procedurally.374327/

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System;
using System.Linq;
 
public class TextureModifier : MonoBehaviour {
 
    // Using Serializable allows us to embed a class with sub properties in the inspector.
    [Serializable]
    public class TextureAttributes{
 
        public string name;
        public int index;
        public bool defaultTexture = false;
        [Range(0.0f,1.0f)]
        public float minSteepness;
        [Range(0.0f,1.0f)]
        public float maxSteepness;
        [Range(0.0f,1.0f)]
        public float minAltitude;
        [Range(0.0f,1.0f)]
        public float maxAltitude;
    }
 
    public List<TextureAttributes> listTextures = new List<TextureAttributes> ();
    private Terrain terrain;
    private TerrainData terrainData;
    private int indexOfDefaultTexture;
 
    void Start () {
 
        // Get the attached terrain component
        terrain = GetComponent<Terrain>();
 
        // Get a reference to the terrain data
        terrainData = terrain.terrainData;
       
        //This is the # of textures you have added in the terrain editor
        int nbTextures = terrainData.alphamapLayers;
       
        //See below for the definition of GetMaxHeight
        float maxHeight = GetMaxHeight(terrainData, terrainData.heightmapWidth);
 
        // Your texture data (i.e. Splatmap) is stored internally as a 3d array of floats with x and y location as the first 2 dimensions of the array and the index of the texture to be used as the 3rd dimension
        float[, ,] splatmapData = new float[terrainData.alphamapWidth, terrainData.alphamapHeight, terrainData.alphamapLayers];
 
        //This is just in case someone mixed up min and max when completing the inspector for this script
        for (int i = 0; i < listTextures.Count; i++) {
            if (listTextures [i].minAltitude > listTextures [i].maxAltitude) {
                float temp = listTextures [i].minAltitude;
                listTextures [i].minAltitude = listTextures [i].maxAltitude;
                listTextures [i].maxAltitude = temp;
            }
 
            if (listTextures [i].minSteepness > listTextures [i].maxSteepness) {
                float temp2 = listTextures [i].minSteepness;
                listTextures [i].minSteepness = listTextures [i].maxSteepness;
                listTextures [i].maxSteepness = temp2;
            }
        }
           
        //For some reason you need a default texture in Unity
        for (int i = 0; i < listTextures.Count; i++) {
            if (listTextures [i].defaultTexture) {
                indexOfDefaultTexture = listTextures [i].index;
            }
        }
 
 
        for (int y = 0; y < terrainData.alphamapHeight; y++)
        {
            for (int x = 0; x < terrainData.alphamapWidth; x++)
            {
                // Normalise x/y coordinates to range 0-1
                float y_01 = (float)y/(float)terrainData.alphamapHeight;
                float x_01 = (float)x/(float)terrainData.alphamapWidth;
 
                // Sample the height at this location (note GetHeight expects int coordinates corresponding to locations in the heightmap array)
                float height = terrainData.GetHeight(Mathf.RoundToInt(y_01 * terrainData.heightmapHeight),Mathf.RoundToInt(x_01 * terrainData.heightmapWidth) );
 
                //Normalise the height by dividing it by maxHeight
                float normHeight = height / maxHeight;
 
                // Calculate the steepness of the terrain at this location
                float steepness = terrainData.GetSteepness(y_01,x_01);
 
                // Normalise the steepness by dividing it by the maximum steepness: 90 degrees
                float normSteepness = steepness / 90.0f;
 
                //Erase existing splatmap at this point
                for(int i = 0; i<terrainData.alphamapLayers; i++){
                    splatmapData [x, y, i] = 0.0f;
                }
 
                // Setup an array to record the mix of texture weights at this point
                float[] splatWeights = new float[terrainData.alphamapLayers];
 
                for (int i = 0; i < listTextures.Count; i++) {
     
                    //The rules you defined in the inspector are being applied for each texture
                    if (normHeight >= listTextures [i].minAltitude && normHeight <= listTextures [i].maxAltitude && normSteepness >= listTextures [i].minSteepness && normSteepness <= listTextures [i].maxSteepness) {
                        splatWeights [listTextures [i].index] = 1.0f;
                    }
                }
 
                // Sum of all textures weights must add to 1, so calculate normalization factor from sum of weights
                float z = splatWeights.Sum();
 
                //If z is 0 at this location (i.e. no texture was applied), put default texture
                if(Mathf.Approximately(z, 0.0f)){
                    splatWeights [indexOfDefaultTexture] = 1.0f;
                }
 
                // Loop through each terrain texture
                for(int i = 0; i<terrainData.alphamapLayers; i++){
 
                    // Normalize so that sum of all texture weights = 1
                    splatWeights[i] /= z;
 
                    // Assign this point to the splatmap array
                    splatmapData[x, y, i] = splatWeights[i];
                }
            }
        }
 
        // Finally assign the new splatmap to the terrainData:
        terrainData.SetAlphamaps(0, 0, splatmapData);
    }
   
    //This is to get the maximum altitude of your terrain. For some reason TerrainData.
    private float GetMaxHeight(TerrainData tData, int heightmapWidth){
 
        float maxHeight = 0f;
 
        for (int x = 0; x < heightmapWidth; x++) {
            for (int y = 0; y < heightmapWidth; y++) {
                if (tData.GetHeight (x, y) > maxHeight) {
                    maxHeight = tData.GetHeight (x, y);
                }
            }
        }
        return maxHeight;
    }
}