create NResUI

NResUI/ImGuiUI/ImGuiModalPanel.cs

@@ -0,0 +1,39 @@
+using System.Numerics;
+using ImGuiNET;
+using NResUI.Abstractions;
+
+namespace NResUI.ImGuiUI;
+
+public abstract class ImGuiModalPanel : IImGuiPanel
+{
+    protected abstract string ImGuiId { get; }
+
+    private bool _shouldOpen = false;
+
+    public virtual void Open()
+    {
+        _shouldOpen = true;
+    }
+
+    protected abstract void OnImGuiRenderContent();
+
+    public void OnImGuiRender()
+    {
+        // this is a ImGui stack fix. Because menubars and some other controls use their separate stack context,
+        // The panel gets rendered on it's own, at the root of the stack, and with _shouldOpen we control, if the panel should open this frame.
+        if (_shouldOpen)
+        {
+            ImGui.OpenPopup(ImGuiId, ImGuiPopupFlags.AnyPopupLevel);
+            _shouldOpen = false;
+        }
+
+        ImGui.SetNextWindowSize(new Vector2(600, 400));
+
+        if (ImGui.BeginPopup(ImGuiId, ImGuiWindowFlags.NoResize))
+        {
+            OnImGuiRenderContent();
+
+            ImGui.EndPopup();
+        }
+    }
+}