unity 计算预制体地图的高度图 代码

以下是基于Unity的C#代码实现预制体地图的高度图计算：

using UnityEngine;
using System.IO;

public class CalculateHeightmap : MonoBehaviour
{
    public GameObject[] prefabs; // 预制体地图
    public int resolution = 1024; // 高度图分辨率
    public float scale = 1f; // 高度图缩放比例

    private TerrainData terrainData;
    private Terrain terrain;

    void Start()
    {
        // 创建一个空的Terrain对象
        terrain = Terrain.CreateTerrainGameObject(new TerrainData()).GetComponent<Terrain>();
        terrainData = terrain.terrainData;

        // 设置地形的分辨率和大小
        terrainData.heightmapResolution = resolution;
        terrainData.size = new Vector3(prefabs[0].transform.localScale.x * prefabs.Length, 
            prefabs[0].transform.localScale.y * prefabs[0].transform.localScale.z, prefabs.Length);

        // 计算高度图
        float[,] heights = new float[resolution, resolution];
        for (int x = 0; x < resolution; x++)
        {
            for (int z = 0; z < resolution; z++)
            {
                float height = 0f;
                for (int i = 0; i < prefabs.Length; i++)
                {
                    Vector3 position = new Vector3(x / (float)resolution * terrainData.size.x, 
                        0f, z / (float)resolution * terrainData.size.z) + prefabs[i].transform.position;
                    RaycastHit hit;
                    if (Physics.Raycast(position, Vector3.down, out hit))
                    {
                        height += hit.distance;
                    }
                }
                heights[x, z] = height / (float)prefabs.Length * scale;
            }
        }
        terrainData.SetHeights(0, 0, heights);

        // 导出高度图
        ExportHeightmap();
    }

    void ExportHeightmap()
    {
        string path = Application.dataPath + "/heightmap.raw";
        FileStream stream = new FileStream(path, FileMode.Create);
        BinaryWriter writer = new BinaryWriter(stream);

        float[,] heights = terrainData.GetHeights(0, 0, resolution, resolution);
        for (int z = 0; z < resolution; z++)
        {
            for (int x = 0; x < resolution; x++)
            {
                writer.Write(heights[x, z]);
            }
        }
        writer.Close();
        stream.Close();
    }
}

以上代码中，我们首先创建一个空的Terrain对象，并设置它的分辨率和大小。然后，我们遍历高度图的每个像素，并对每个像素计算出它的高度值。计算高度值时，我们将每个预制体地图的位置向下发射一条射线，得到它与地面的距离，并将所有距离的平均值作为该像素的高度值。最后，我们将得到的高度图保存为一个.raw文件。