prototype fix

The issue is that, create UI in Update (like in TestFei.cs) will cause crash. this is just a prototype fix: only latch2 part is useful. we will look into this issue later when having time

engine/src/shell/platform/unity/windows/uiwidgets_panel.cc

 
 namespace uiwidgets {
 
+	std::thread::id gfx_worker_thread_id;
+
+	int worker_set = 0;
+
 fml::RefPtr<UIWidgetsPanel> UIWidgetsPanel::Create(
     Mono_Handle handle, UIWidgetsWindowType window_type, EntrypointCallback entrypoint_callback) {
   return fml::MakeRefCounted<UIWidgetsPanel>(handle, window_type, entrypoint_callback);
                               size_t height, float device_pixel_ratio,
                               const char* streaming_assets_path,
                               const char* settings) {
+
+	fml::AutoResetWaitableEvent latch2;
+  // std::thread::id gfx_worker_thread_id;
+  UIWidgetsSystem::GetInstancePtr()->PostTaskToGfxWorker([&latch2]() -> void {
+    latch2.Signal();
+  });
+  latch2.Wait();
+
   surface_manager_ = std::make_unique<UnitySurfaceManager>(
       UIWidgetsSystem::GetInstancePtr()->GetUnityInterfaces());
 
   
   surface_manager_->ClearCurrent();
 
-  fml::AutoResetWaitableEvent latch;
-  std::thread::id gfx_worker_thread_id;
-  UIWidgetsSystem::GetInstancePtr()->PostTaskToGfxWorker(
-      [&latch, &gfx_worker_thread_id]() -> void {
-        gfx_worker_thread_id = std::this_thread::get_id();
-        latch.Signal();
-      });
-  latch.Wait();
+  if (worker_set == 0)
+  {
+	  fml::AutoResetWaitableEvent latch;
+	  //std::thread::id gfx_worker_thread_id;
+	  UIWidgetsSystem::GetInstancePtr()->PostTaskToGfxWorker(
+		  [&latch]() -> void {
+			gfx_worker_thread_id = std::this_thread::get_id();
+			latch.Signal();
+		  });
+	  latch.Wait();
+
+	  worker_set = 1;
+  }
 
   gfx_worker_task_runner_ = std::make_unique<GfxWorkerTaskRunner>(
       gfx_worker_thread_id, [this](const auto* task) {

Samples/UIWidgetsSamples_2019_4/Assets/Script/TestFei.cs

+using UnityEngine;
+using UnityEngine.UI;
+
+namespace UIWidgetsSample
+{
+    public class TestFei : MonoBehaviour
+    {
+        private float curTime = 0.0f;
+
+        private int totalNum = 10;
+
+        private bool isOk = false;
+
+        public static bool needwaiting = false;
+        
+        private void Update()
+        {
+            if (Input.GetKeyDown(KeyCode.A))
+            {
+                this.isOk = true;
+            }
+
+            if (!this.isOk)
+            {
+                return;
+            }
+
+            //if (needwaiting)
+            //{
+            //    return;
+            //}
+            
+            if (this.totalNum <= 0)
+            {
+                return;
+            }
+            
+            this.curTime += Time.deltaTime;
+            if (this.curTime < 0)
+            {
+                return;
+            }
+
+            this.curTime = 0;
+            this.totalNum--;
+
+            //needwaiting = true;
+            //for (int i = 0; i < 10; i++)
+            {
+                GameObject gameobject = new GameObject();
+                GameObject newCanvas = new GameObject();
+
+                Canvas c = newCanvas.AddComponent<Canvas>();
+                c.renderMode = RenderMode.WorldSpace;
+
+                newCanvas.AddComponent<CanvasScaler>();
+                newCanvas.AddComponent<GraphicRaycaster>();
+
+                var canvasTransform = c.GetComponent<RectTransform>();
+                canvasTransform.anchorMin = new Vector2(0, 0);
+                canvasTransform.anchorMax = new Vector2(0, 0);
+                canvasTransform.sizeDelta = new Vector2(800, 800);
+
+                GameObject panel = new GameObject("RawImage");
+                var rectTransform = panel.AddComponent<RectTransform>();
+                rectTransform.anchorMin = new Vector2(0, 0);
+                rectTransform.anchorMax = new Vector2(1, 1);
+                rectTransform.offsetMin = new Vector2(0, 0);
+                rectTransform.offsetMax = new Vector2(0, 0);
+
+                panel.AddComponent<CanvasRenderer>();
+                panel.AddComponent<HoverSample>();
+                panel.transform.SetParent(newCanvas.transform, false);
+                newCanvas.transform.SetParent(gameobject.transform, true);
+            }
+        }
+    }
+}

Samples/UIWidgetsSamples_2019_4/Assets/Script/TestFei.cs.meta

+fileFormatVersion: 2
+guid: 3e9daa87a52a47e488207acb4a2a0bd0
+timeCreated: 1645414930