增加skill、加入界面基础加载

Assets/Scripts/UI/MainMenu.cs

@@ -0,0 +1,54 @@
+using System.Collections;
+using UnityEngine;
+using UnityEngine.SceneManagement;
+
+/// <summary>
+/// Main 启动页。
+/// 点击事件在 Button 的 On Click() 里接线（Inspector 配置），代码里不查找节点。
+/// </summary>
+public class MainMenu : MonoBehaviour
+{
+    [Tooltip("点「启动」后要加载的场景名，必须已经加进 Build Settings")]
+    [SerializeField] private string startSceneName = "Start";
+
+    private bool _loading;
+
+    /// <summary>启动：加载目标场景，加载完成后卸载 Main 场景自己。</summary>
+    public void OnStartClicked()
+    {
+        if (_loading) return;   // 防连点，避免同时加载出两份
+        _loading = true;
+        StartCoroutine(LoadThenUnloadSelf());
+    }
+
+    /// <summary>退出游戏。</summary>
+    public void OnExitClicked()
+    {
+        Application.Quit();
+#if UNITY_EDITOR
+        // 编辑器里 Application.Quit 不生效，方便本地测试
+        UnityEditor.EditorApplication.isPlaying = false;
+#endif
+    }
+
+    private IEnumerator LoadThenUnloadSelf()
+    {
+        Scene mainScene = gameObject.scene;
+
+        AsyncOperation load = SceneManager.LoadSceneAsync(startSceneName, LoadSceneMode.Additive);
+        if (load == null)
+        {
+            Debug.LogError("[MainMenu] 场景 \"" + startSceneName + "\" 加载失败，确认它已加入 Build Settings。", this);
+            _loading = false;
+            yield break;
+        }
+
+        yield return load;   // 等目标场景加载完成
+
+        Scene loaded = SceneManager.GetSceneByName(startSceneName);
+        if (loaded.IsValid())
+            SceneManager.SetActiveScene(loaded);
+
+        SceneManager.UnloadSceneAsync(mainScene);   // 加载完成后卸载 Main
+    }
+}