From 60482059a426f0d82bc7b42d2df7ac6903836ed4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20L=C3=BCbe=C3=9F?= <simon.luebess@gmail.com>
Date: Tue, 17 Jun 2025 16:46:05 +0200
Subject: [PATCH] Test handle Windows Explorer drag'n'drop in ImGui

---
 .../src/EditWindows/ContentBrowserWindow.bf   | 19 +++++++++
 GlitchyEditor/src/EditorLayer.bf              | 42 ++++++++++++++++---
 GlitchyEditor/src/ImGuiExtension.bf           |  3 ++
 GlitchyEngine/src/ImGui/ImGuiLayer.bf         |  2 +-
 4 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/GlitchyEditor/src/EditWindows/ContentBrowserWindow.bf b/GlitchyEditor/src/EditWindows/ContentBrowserWindow.bf
index b9cd06f..53bb485 100644
--- a/GlitchyEditor/src/EditWindows/ContentBrowserWindow.bf
+++ b/GlitchyEditor/src/EditWindows/ContentBrowserWindow.bf
@@ -187,6 +187,25 @@ namespace GlitchyEditor.EditWindows
 				}
 
 				ImGui.EndTable();
+				
+				if (ImGui.BeginDragDropTarget())
+				{
+					ImGui.Payload* peekPayload = ImGui.AcceptDragDropPayload(.ExternFiles, .AcceptBeforeDelivery);
+
+					if (peekPayload != null)
+					{
+						if (peekPayload.IsDelivery())
+						{
+							Log.EngineLogger.Info("Buup!");
+						}
+						else
+						{
+							EditorLayer.SetDropEffect(.Copy);
+						}
+					}
+
+					ImGui.EndDragDropTarget();
+				}
 			}
 
 			ImGui.PopStyleVar(1);
diff --git a/GlitchyEditor/src/EditorLayer.bf b/GlitchyEditor/src/EditorLayer.bf
index d0babcb..a214953 100644
--- a/GlitchyEditor/src/EditorLayer.bf
+++ b/GlitchyEditor/src/EditorLayer.bf
@@ -135,7 +135,7 @@ namespace GlitchyEditor
 
 			public override Result<void> OnDragLeave()
 			{
-				DragDropEvent event = scope DragDropEvent(.Over, .(-1, -1));
+				DragDropEvent event = scope DragDropEvent(.Leave, .(-1, -1));
 				Application.Instance.OnEvent(event);
 				return .Ok;
 			}
@@ -149,7 +149,7 @@ namespace GlitchyEditor
 		}
 
 		private GlobalDragDropTarget _dragDropTarget ~ _?.ReleaseRef();
-
+		
 		[AllowAppend]
 		public this(String[] args, EditorContentManager contentManager) : base("Editor")
 		{
@@ -157,6 +157,9 @@ namespace GlitchyEditor
 
 			ScriptEngine.ApplicationInfo.IsEditor = true;
 
+			// TODO: Das muss weg
+			_layer = this;
+
 			_dragDropTarget = new .();
 			_dragDropTarget.Register();
 
@@ -1201,6 +1204,17 @@ namespace GlitchyEditor
 			ImGui.Viewport* viewport = ImGui.GetMainViewport();
 			ImGui.DockSpaceOverViewport(viewport);
 
+			if (_isDraggingFromOutside)
+			{
+				SetDropEffect(.None);
+
+				if (ImGui.BeginDragDropSource(.SourceExtern | .SourceAutoExpirePayload))
+				{
+					ImGui.SetDragDropPayload(.ExternFiles, null, 0);
+					ImGui.EndDragDropSource();
+				}
+			}
+
 			DrawMainMenuBar();
 
 #if GE_EDITOR_IMGUI_DEMO
@@ -1657,23 +1671,41 @@ namespace GlitchyEditor
 		}
 
 		private bool _isDraggingFromOutside;
-		private bool _droppedFromOutside;
 		private DropEffect _effectWhenDropping = .None;
 
+		private static EditorLayer _layer;
+
+		public static void SetDropEffect(DropEffect effect)
+		{
+			if (!_layer._isDraggingFromOutside)
+			{
+				Log.EngineLogger.Warning("Setting drop effect, eventhou the user is currently not dragging.");
+			}
+
+			_layer._effectWhenDropping = effect;
+		}
+
 		private bool OnDragDrop(DragDropEvent e)
 		{
 			Log.EngineLogger.Info($"D'n'D: {e.DragDropType} {e.CursorPosition.X} {e.CursorPosition.Y}");
 
+			if (all(e.CursorPosition != .(-1,-1)))
+			{
+				ImGui.GetIO().MousePos = .(e.CursorPosition.X, e.CursorPosition.Y);
+			}
+
 			switch (e.DragDropType)
 			{
 			case .Enter:
 				_isDraggingFromOutside = true;
-				_droppedFromOutside = false;
+				ImGui.GetIO().MouseDown[0] = true;
 			case .Over:
 			case .Leave:
 				_isDraggingFromOutside = false;
+				ImGui.ClearDragDrop();
 			case .Drop:
-				_droppedFromOutside = true;
+				_isDraggingFromOutside = false;
+				ImGui.GetIO().MouseDown[0] = false;
 			}
 
 			e.OutDropEffect = _effectWhenDropping;
diff --git a/GlitchyEditor/src/ImGuiExtension.bf b/GlitchyEditor/src/ImGuiExtension.bf
index 668a427..3a3ef6e 100644
--- a/GlitchyEditor/src/ImGuiExtension.bf
+++ b/GlitchyEditor/src/ImGuiExtension.bf
@@ -6,6 +6,7 @@ enum DragDropPayloadType
 {
 	case ContentBrowserItem;
 	case Entity;
+	case ExternFiles;
 
 	public String GetName()
 	{
@@ -15,6 +16,8 @@ enum DragDropPayloadType
 			return "CONTENT_BROWSER_ITEM";
 		case .Entity:
 			return "ENTITY";
+		case .ExternFiles:
+			return "EXTERN_FILES";
 		}
 	}
 }
diff --git a/GlitchyEngine/src/ImGui/ImGuiLayer.bf b/GlitchyEngine/src/ImGui/ImGuiLayer.bf
index 847536b..51dbde4 100644
--- a/GlitchyEngine/src/ImGui/ImGuiLayer.bf
+++ b/GlitchyEngine/src/ImGui/ImGuiLayer.bf
@@ -220,7 +220,7 @@ namespace GlitchyEngine.ImGui
 				Debug.Profiler.ProfileScope!("ImGuiRenderEvent");
 
 				var event = scope ImGuiRenderEvent();
-				Application.Get().OnEvent(event);
+				Application.Instance.OnEvent(event);
 			}
 
 			End();