using UnityEngine;
using UnityEngine.UI;
using System.IO;

public class ImageBlender : MonoBehaviour
{
    [Header("绑定设置")]
    public Image imageA; // 底图
    public Image imageB; // 顶图
    public Shader blendShader;

    [Header("导出设置")]
    public string fileName = "Blended_Result";
    public string saveFolder = "Exports";

    void Start()
    {
        // 自动获取Shader（可选）
        if (!blendShader) blendShader = Shader.Find("Custom/SimpleBlend");
    }

    [ContextMenu("执行混合导出")]
    public void ExecuteBlendExport()
    {
        // 获取原始纹理
        Texture2D texA = GetImageTexture(imageA);
        Texture2D texB = GetImageTexture(imageB);

        // 创建临时RenderTexture
        RenderTexture rt = new RenderTexture(texA.width, texA.height, 24);

        // 创建混合材质
        Material blendMat = new Material(blendShader);
        blendMat.SetTexture("_MainTex", texA);
        blendMat.SetTexture("_BlendTex", texB);

        // 执行混合
        Graphics.Blit(null, rt, blendMat);

        // 转换为Texture2D
        Texture2D output = RenderTextureToTexture2D(rt);

        // 保存文件
        SaveTextureAsPNG(output);

        // 清理资源
        DestroyImmediate(rt);
        DestroyImmediate(output);
    }

    Texture2D GetImageTexture(Image image)
    {
        // 从Image组件获取纹理
        Sprite sprite = image.sprite;
        Texture2D originTex = sprite.texture;
        
        // 创建可读写副本
        Texture2D copyTex = new Texture2D(originTex.width, originTex.height, originTex.format, false);
        copyTex.SetPixels(originTex.GetPixels());
        copyTex.Apply();
        return copyTex;
    }

    Texture2D RenderTextureToTexture2D(RenderTexture rt)
    {
        RenderTexture.active = rt;
        Texture2D tex = new Texture2D(rt.width, rt.height, TextureFormat.ARGB32, false);
        tex.ReadPixels(new Rect(0, 0, rt.width, rt.height), 0, 0);
        tex.Apply();
        RenderTexture.active = null;
        return tex;
    }

    void SaveTextureAsPNG(Texture2D tex)
    {
        byte[] bytes = tex.EncodeToPNG();
        string dirPath = Path.Combine(Application.streamingAssetsPath, saveFolder);
        if (!Directory.Exists(dirPath)) Directory.CreateDirectory(dirPath);
        
        string filePath = Path.Combine(dirPath, fileName + ".png");
        File.WriteAllBytes(filePath, bytes);
        Debug.Log($"导出成功：{filePath}");
    }
}