通过Texture2D的EncodeToPNG方法将纹理转为图片形式

material.GetTexture方法通过属性名获取纹理贴图

material.SetTexture方法通过属性名设置纹理贴图

属性名可在shader代码中查看

using UnityEngine;
using System.IO;

public class TextureSaver : MonoBehaviour
{
    public Material targetMaterial;
    public string textureName = "_MainTex"; // 可自定义材质属性名

    public void SaveMaterialTexture()
    {
        if (targetMaterial == null)
        {
            Debug.LogError("未指定目标材质球！");
            return;
        }

        Texture mainTex = targetMaterial.GetTexture(textureName);
        if (mainTex == null)
        {
            Debug.LogError($"材质中未找到纹理属性：{textureName}");
            return;
        }

        if (mainTex is Texture2D)
        {
            SaveTexture2D(mainTex as Texture2D);
        }
        else if (mainTex is RenderTexture)
        {
            SaveRenderTexture(mainTex as RenderTexture);
        }
        else
        {
            Debug.LogError("不支持此纹理类型：" + mainTex.GetType());
        }
    }

    void SaveTexture2D(Texture2D texture)
    {
        if (!texture.isReadable)
        {
            Debug.LogError("纹理不可读！请在导入设置中启用 Read/Write Enabled");
            return;
        }

        byte[] bytes = texture.EncodeToPNG();
        string filePath = Path.Combine(Application.persistentDataPath, "SavedTexture.png");
        File.WriteAllBytes(filePath, bytes);
        Debug.Log("保存成功：" + filePath);
    }

    void SaveRenderTexture(RenderTexture rt)
    {
        Texture2D tex2D = new Texture2D(rt.width, rt.height, TextureFormat.RGBA32, false);
        RenderTexture.active = rt;
        tex2D.ReadPixels(new Rect(0, 0, rt.width, rt.height), 0, 0);
        tex2D.Apply();
        RenderTexture.active = null;

        SaveTexture2D(tex2D);
        Destroy(tex2D);
    }
}