using UnityEngine;
using System;
using MindPowerSdk;
using UnityEngine;

public static class AtlasBuilder
{
    /// <summary>
    /// 将 textures 中的贴图每 countPerAtlas 张打包成一个图集，默认图集尺寸为 2048。
    /// </summary>
    /// <param name="textures">所有原始贴图，数量应为 countPerAtlas 的倍数</param>
    /// <param name="countPerAtlas">每个图集中包含的贴图数量（例如 16）</param>
    /// <param name="atlasSize">图集尺寸</param>
    /// <returns>打包好的图集数组</returns>
    public static Texture2D[] BuildAtlases(Texture2D[] textures, int countPerAtlas, int atlasSize = 2048)
    {
        int         atlasCount = textures.Length / countPerAtlas;
        Texture2D[] atlases    = new Texture2D[atlasCount];
        for (int i = 0; i < atlasCount; i++)
        {
            Texture2D   atlas = new Texture2D(atlasSize, atlasSize, TextureFormat.RGBA32, false);
            Texture2D[] group = new Texture2D[countPerAtlas];
            for (int j = 0; j < countPerAtlas; j++)
            {
                group[j] = textures[i * countPerAtlas + j];
            }

            // 自动打包，第二个参数表示边距（像素），atlasSize 限制最大尺寸
            atlas.PackTextures(group, 2, atlasSize);
            atlases[i] = atlas;
        }

        return atlases;
    }
}

public static class TerrainLayerBuilder
{
    /// <summary>
    /// 从 4 个图集创建 TerrainLayer，每个图集对应一个层
    /// </summary>
    /// <param name="atlases">必须包含 4 个图集</param>
    /// <returns>TerrainLayer 数组</returns>
    public static TerrainLayer[] BuildTerrainLayers(Texture2D[] atlases)
    {
        if (atlases.Length != 4)
        {
            Debug.LogError("期望传入 4 个图集贴图");
            return null;
        }

        TerrainLayer[] layers = new TerrainLayer[4];
        for (int i = 0; i < 4; i++)
        {
            TerrainLayer tl = new TerrainLayer();
            tl.diffuseTexture = atlases[i];
            // 假设图集内为 4×4 布局，每个子贴图尺寸为 atlas 尺寸的 1/4
            tl.tileSize = new Vector2(tl.diffuseTexture.width / 4f, tl.diffuseTexture.height / 4f);
            layers[i]   = tl;
        }

        return layers;
    }
}