Allow dragging and dropping of Entities in editor

+ New Dictionary Helpers
+ Made ImGui Payloads safer
+ Start of Component drag'n'drop

GlitchyEditor/src/Assets/MaterialAssetLoader.bf

@@ -33,7 +33,7 @@ class MaterialAssetPropertiesEditor : AssetPropertiesEditor
 
 		if (ImGui.BeginDragDropTarget())
 		{
-			ImGui.Payload* payload = ImGui.AcceptDragDropPayload("CONTENT_BROWSER_ITEM");
+			ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.ContentBrowserItem);
 			
 			if (payload != null)
 			{
@@ -78,7 +78,7 @@ class MaterialAssetPropertiesEditor : AssetPropertiesEditor
 
 			if (ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload("CONTENT_BROWSER_ITEM");
+				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.ContentBrowserItem);
 
 				if (payload != null)
 				{

GlitchyEditor/src/EditWindows/ComponentEditWindow.bf

@@ -7,6 +7,8 @@ using GlitchyEngine.Renderer;
 using GlitchyEngine;
 using GlitchyEngine.Content;
 using GlitchyEngine.Scripting;
+using GlitchyEngine.Core;
+using Mono;
 
 namespace GlitchyEditor.EditWindows
 {
@@ -278,7 +280,7 @@ namespace GlitchyEditor.EditWindows
 
 			if (ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload("CONTENT_BROWSER_ITEM");
+				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.ContentBrowserItem);
 
 				if (payload != null)
 				{
@@ -306,7 +308,7 @@ namespace GlitchyEditor.EditWindows
 
 			if (ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload("CONTENT_BROWSER_ITEM");
+				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.ContentBrowserItem);
 
 				if (payload != null)
 				{
@@ -338,7 +340,7 @@ namespace GlitchyEditor.EditWindows
 
 			if (ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload("CONTENT_BROWSER_ITEM");
+				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.ContentBrowserItem);
 
 				if (payload != null)
 				{
@@ -601,94 +603,94 @@ namespace GlitchyEditor.EditWindows
 			{
 				let scriptFields = ScriptEngine.GetScriptFieldMap(entity);
 
-				for (var (name, field) in ref scriptFields)
+				for (var (fieldName, field) in ref scriptFields)
 				{
 					switch (field.Type)
 					{
 					case .Bool:
 						var value = field.GetData<bool>();
-						if (ImGui.Checkbox(name.CStr(), &value))
+						if (ImGui.Checkbox(fieldName.CStr(), &value))
 							field.SetData(value);
 
 					case .SByte:
 						var value = field.GetData<int8>();
-						if (ImGui.DragScalar(name.CStr(), .S8, &value))
+						if (ImGui.DragScalar(fieldName.CStr(), .S8, &value))
+							field.SetData(value);
+					case .Short:
+						var value = field.GetData<int16>();
+						if (ImGui.DragScalar(fieldName.CStr(), .S16, &value))
 							field.SetData(value);
-						case .Short:
-							var value = field.GetData<int16>();
-							if (ImGui.DragScalar(name.CStr(), .S16, &value))
-								field.SetData(value);
 					case .Int:
-							var value = field.GetData<int32>();
-							if (ImGui.DragScalar(name.CStr(), .S32, &value))
-								field.SetData(value);
+						var value = field.GetData<int32>();
+						if (ImGui.DragScalar(fieldName.CStr(), .S32, &value))
+							field.SetData(value);
 					case .Int2:
-							var value = field.GetData<int2>();
-							if (ImGui.DragScalarN(name.CStr(), .S32, &value, 2))
-								field.SetData(value);
+						var value = field.GetData<int2>();
+						if (ImGui.DragScalarN(fieldName.CStr(), .S32, &value, 2))
+							field.SetData(value);
 					case .Int3:
-							var value = field.GetData<int3>();
-							if (ImGui.DragScalarN(name.CStr(), .S32, &value, 3))
-								field.SetData(value);
+						var value = field.GetData<int3>();
+						if (ImGui.DragScalarN(fieldName.CStr(), .S32, &value, 3))
+							field.SetData(value);
 					case .Int4:
-							var value = field.GetData<int4>();
-							if (ImGui.DragScalarN(name.CStr(), .S32, &value, 4))
-								field.SetData(value);
+						var value = field.GetData<int4>();
+						if (ImGui.DragScalarN(fieldName.CStr(), .S32, &value, 4))
+							field.SetData(value);
 					case .Long:
-							var value = field.GetData<int64>();
-							if (ImGui.DragScalar(name.CStr(), .S64, &value))
-								field.SetData(value);
+						var value = field.GetData<int64>();
+						if (ImGui.DragScalar(fieldName.CStr(), .S64, &value))
+							field.SetData(value);
 
 					case .Byte:
-							var value = field.GetData<uint8>();
-							if (ImGui.DragScalar(name.CStr(), .U8, &value))
-								field.SetData(value);
+						var value = field.GetData<uint8>();
+						if (ImGui.DragScalar(fieldName.CStr(), .U8, &value))
+							field.SetData(value);
 					case .UShort:
-							var value = field.GetData<uint16>();
-							if (ImGui.DragScalar(name.CStr(), .U16, &value))
-								field.SetData(value);
+						var value = field.GetData<uint16>();
+						if (ImGui.DragScalar(fieldName.CStr(), .U16, &value))
+							field.SetData(value);
 					case .UInt:
-							var value = field.GetData<uint32>();
-							if (ImGui.DragScalar(name.CStr(), .U32, &value))
-								field.SetData(value);
+						var value = field.GetData<uint32>();
+						if (ImGui.DragScalar(fieldName.CStr(), .U32, &value))
+							field.SetData(value);
 					case .ULong:
-							var value = field.GetData<uint64>();
-							if (ImGui.DragScalar(name.CStr(), .U64, &value))
-								field.SetData(value);
+						var value = field.GetData<uint64>();
+						if (ImGui.DragScalar(fieldName.CStr(), .U64, &value))
+							field.SetData(value);
 
 					case .Float:
-							var value = field.GetData<float>();
-							if (ImGui.DragScalar(name.CStr(), .Float, &value))
-								field.SetData(value);
+						var value = field.GetData<float>();
+						if (ImGui.DragScalar(fieldName.CStr(), .Float, &value))
+							field.SetData(value);
 					case .float2:
-							var value = field.GetData<float2>();
-							if (ImGui.Editfloat2(name, ref value))
-								field.SetData(value);
+						var value = field.GetData<float2>();
+						if (ImGui.Editfloat2(fieldName, ref value))
+							field.SetData(value);
 					case .float3:
-							var value = field.GetData<float3>();
-							if (ImGui.Editfloat3(name, ref value))
-								field.SetData(value);
+						var value = field.GetData<float3>();
+						if (ImGui.Editfloat3(fieldName, ref value))
+							field.SetData(value);
 					case .float4:
-							var value = field.GetData<float4>();
-							if (ImGui.Editfloat4(name, ref value))
-								field.SetData(value);
+						var value = field.GetData<float4>();
+						if (ImGui.Editfloat4(fieldName, ref value))
+							field.SetData(value);
 
 					case .Double:
-							var value = field.GetData<double>();
-							if (ImGui.DragScalar(name.CStr(), .Double, &value))
-								field.SetData(value);
+						var value = field.GetData<double>();
+						if (ImGui.DragScalar(fieldName.CStr(), .Double, &value))
+							field.SetData(value);
 					case .Double2:
-							var value = field.GetData<double2>();
-							if (ImGui.DragScalarN(name.CStr(), .Double, &value, 2))
-								field.SetData(value);
+						var value = field.GetData<double2>();
+						if (ImGui.DragScalarN(fieldName.CStr(), .Double, &value, 2))
+							field.SetData(value);
 					case .Double3:
-							var value = field.GetData<double3>();
-							if (ImGui.DragScalarN(name.CStr(), .Double, &value, 3))
-								field.SetData(value);
+						var value = field.GetData<double3>();
+						if (ImGui.DragScalarN(fieldName.CStr(), .Double, &value, 3))
+							field.SetData(value);
 					case .Double4:
-							var value = field.GetData<double4>();
-							if (ImGui.DragScalarN(name.CStr(), .Double, &value, 4))
-								field.SetData(value);
+						var value = field.GetData<double4>();
+						if (ImGui.DragScalarN(fieldName.CStr(), .Double, &value, 4))
+							field.SetData(value);
 
 					case .Enum:
 						// TODO!
@@ -697,11 +699,16 @@ namespace GlitchyEditor.EditWindows
 						// TODO!
 
 					case .Entity:
-						// TODO!
+						ShowEntityReceiver(field, fieldName, scriptClass);
+					case .Component:
+						ShowComponentReceiver(field, fieldName, scriptClass);
 
 					case .Struct:
 						// TODO!
 
+					case .Class:
+						// We don't support editing classes
+
 					default:
 						Log.EngineLogger.Error($"Unhandled field type {field.Type}");
 					}
@@ -709,6 +716,133 @@ namespace GlitchyEditor.EditWindows
 			}
 		}
 
+		private static void ShowEntityReceiver(ScriptFieldInstance* field, StringView fieldName, ScriptClass scriptClass)
+		{
+			var entityId = field.GetData<UUID>();
+
+			Result<Entity> fieldEntity = Editor.Instance.CurrentScene.GetEntityByID(entityId);
+
+			String entityName = scope .(32);
+
+			if (fieldEntity case .Ok(Entity e))
+				entityName.Set(e.Name);
+			else
+				entityName..Clear().AppendF($"Missing entity ({entityId})");
+
+			ImGui.Text($"{fieldName}: ");
+			ImGui.SameLine();
+
+			if (ImGui.Button(entityName))
+			{
+				// TODO: Show a selector or something
+			}
+
+			if (ImGui.BeginDragDropTarget())
+			{
+				ImGui.Payload* peekPayload = ImGui.AcceptDragDropPayload(.Entity, .AcceptPeekOnly);
+
+				bool allowDrop = false;
+
+				if (peekPayload != null)
+				{
+					Entity draggedEntity = *(Entity*)peekPayload.Data;
+
+					ScriptClass draggedScriptClass = ScriptEngine.[Friend]s_EntityRoot;
+
+					if (draggedEntity.TryGetComponent<ScriptComponent>(let draggedScript))
+					{
+						var draggedClassName = draggedScript.ScriptClassName;
+						draggedScriptClass = ScriptEngine.GetScriptClass(draggedClassName);
+
+					}
+
+					// TODO: I don't like the fact, that we are using mono directly
+
+					ScriptField scriptField = scriptClass.Fields[fieldName];
+					var fieldMonoClass = Mono.mono_type_get_class(scriptField.GetMonoType());
+
+					allowDrop = draggedScriptClass.[Friend]IsSubclass(fieldMonoClass);
+				}
+
+				if (allowDrop)
+				{
+					ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.Entity);
+
+					if (payload != null)
+					{
+						Log.EngineLogger.AssertDebug(payload.DataSize == sizeof(Entity));
+
+						Entity droppedEntity = *(Entity*)payload.Data;
+
+						if (droppedEntity.IsValid)
+							field.SetData<UUID>(droppedEntity.UUID);
+					}
+				}
+
+				ImGui.EndDragDropTarget();
+			}
+		}
+
+		private static void ShowComponentReceiver(ScriptFieldInstance* field, StringView fieldName, ScriptClass scriptClass)
+		{
+			var entityId = field.GetData<UUID>();
+
+			Result<Entity> fieldEntity = Editor.Instance.CurrentScene.GetEntityByID(entityId);
+
+			String entityName = scope .(32);
+
+			if (fieldEntity case .Ok(Entity e))
+				entityName.Set(e.Name);
+			else
+				entityName..Clear().AppendF($"Missing reference ({entityId})");
+
+			ImGui.Text($"{fieldName}: ");
+			ImGui.SameLine();
+
+			if (ImGui.Button(entityName))
+			{
+				// TODO: Show a selector or something
+			}
+
+			if (ImGui.BeginDragDropTarget())
+			{
+				ImGui.Payload* peekPayload = ImGui.AcceptDragDropPayload(.Entity, .AcceptPeekOnly);
+
+				bool allowDrop = false;
+
+				if (peekPayload != null)
+				{
+					Entity draggedEntity = *(Entity*)peekPayload.Data;
+
+					// TODO: I don't like the fact, that we are using mono directly
+
+					ScriptField scriptField = scriptClass.Fields[fieldName];
+					MonoReflectionType* reflectionType = Mono.mono_type_get_object(ScriptEngine.[Friend]s_AppDomain, scriptField.GetMonoType());
+
+					// TODO: We shouldn't abuse the script glue like that...
+					// ScriptGlue should only be called by C#, not by Beef...
+					allowDrop = ScriptGlue.[Friend]Entity_HasComponent(draggedEntity.UUID, reflectionType);
+				}
+
+				if (allowDrop)
+				{
+					ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.Entity);
+
+					if (payload != null)
+					{
+						Log.EngineLogger.AssertDebug(payload.DataSize == sizeof(Entity));
+
+						Entity droppedEntity = *(Entity*)payload.Data;
+
+						if (droppedEntity.IsValid)
+							field.SetData<UUID>(droppedEntity.UUID);
+					}
+				}
+
+				ImGui.EndDragDropTarget();
+			}
+		}
+
 		private static void LabelColumn(StringView label)
 		{
 			ImGui.TextUnformatted(label);
@@ -773,7 +907,7 @@ namespace GlitchyEditor.EditWindows
 
 			if (ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload("CONTENT_BROWSER_ITEM");
+				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.ContentBrowserItem);
 
 				if (payload != null)
 				{

GlitchyEditor/src/EditWindows/ContentBrowserWindow.bf

@@ -324,7 +324,7 @@ namespace GlitchyEditor.EditWindows
 
 				Path.Fixup(fullpath);
 
-				ImGui.SetDragDropPayload("CONTENT_BROWSER_ITEM", fullpath.CStr(), (.)fullpath.Length, .Once);
+				ImGui.SetDragDropPayload(.ContentBrowserItem, fullpath.CStr(), (.)fullpath.Length, .Once);
 
 				ImGui.EndDragDropSource();
 			}
@@ -370,7 +370,7 @@ namespace GlitchyEditor.EditWindows
 						String fullpath = scope String(entry->Path);
 						fullpath.AppendF($"#{subAsset.Name}");
 
-						ImGui.SetDragDropPayload("CONTENT_BROWSER_ITEM", fullpath.CStr(), (.)fullpath.Length, .Once);
+						ImGui.SetDragDropPayload(.ContentBrowserItem, fullpath.CStr(), (.)fullpath.Length, .Once);
 		
 						ImGui.EndDragDropSource();
 					}

GlitchyEditor/src/EditWindows/EditorViewportWindow.bf

@@ -137,7 +137,7 @@ namespace GlitchyEditor.EditWindows
 		{
 			if (ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload("CONTENT_BROWSER_ITEM");
+				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.ContentBrowserItem);
 
 				if (payload != null)
 				{

GlitchyEditor/src/EditWindows/EntityHierarchyWindow.bf

@@ -341,9 +341,13 @@ namespace GlitchyEditor.EditWindows
 			if (deleted)
 				return;
 
+			bool isDragged = false;
+
 			if(ImGui.BeginDragDropSource())
 			{
-				ImGui.SetDragDropPayload("DND_Entity", &tree.Value, sizeof(Entity));
+				isDragged = true;
+
+				ImGui.SetDragDropPayload(.Entity, &tree.Value, sizeof(Entity));
 
 				ImGui.Text(name);
 
@@ -352,7 +356,7 @@ namespace GlitchyEditor.EditWindows
 
 			if(ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload("DND_Entity");
+				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.Entity);
 
 				if(payload != null)
 				{
@@ -395,7 +399,7 @@ namespace GlitchyEditor.EditWindows
 
 			bool clicked = ImGui.IsItemClicked(.Left);
 			bool clickedRight = ImGui.IsItemClicked(.Right);
-
+			
 			if(isOpen)
 			{
 				for(var child in tree.Children)
@@ -407,6 +411,12 @@ namespace GlitchyEditor.EditWindows
 			}
 
 			if (clicked || clickedRight)
+			{
+				lastClickedEntity = tree.Value;
+			}
+
+			//if (!isDragged && (clicked || clickedRight))
+			if (!isDragged && (!ImGui.IsMouseDown(.Left) && !ImGui.IsMouseDown(.Right) && ImGui.IsItemHovered()) && tree.Value == lastClickedEntity)
 			{
 				if (inSelectedList && !clickedRight)
 				{
@@ -418,9 +428,13 @@ namespace GlitchyEditor.EditWindows
 					SelectEntity(tree.Value, !ImGui.GetIO().KeyCtrl && !clickedRight);
 					inSelectedList = true;
 				}
+
+				lastClickedEntity = .();
 			}
 		}
 
+		private static Entity lastClickedEntity;
+
 		private void ShowEntityHierarchy()
 		{
 			StringView searchString = StringView(&_entitySearchChars);
@@ -464,7 +478,7 @@ namespace GlitchyEditor.EditWindows
 				{
 					if(ImGui.BeginDragDropTarget())
 					{
-						ImGui.Payload* payload = ImGui.AcceptDragDropPayload("DND_Entity");
+						ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.Entity);
 
 						if(payload != null)
 						{
@@ -527,6 +541,10 @@ namespace GlitchyEditor.EditWindows
 					ImGuiPrintEntityTree(scope .(entity));
 				}
 			}
+
+			// If the mouse was released and no entity took the chance to become selected we probably hovered the background while releasing -> select no entity
+			if (!ImGui.IsMouseDown(.Left) && !ImGui.IsMouseDown(.Right))
+				lastClickedEntity = .();
 		}
 	}
 }

GlitchyEditor/src/EditWindows/GameViewportWindow.bf

@@ -91,7 +91,7 @@ namespace GlitchyEditor.EditWindows
 		{
 			if (ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload("CONTENT_BROWSER_ITEM");
+				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.ContentBrowserItem);
 
 				if (payload != null)
 				{

GlitchyEditor/src/Editor.bf

@@ -53,9 +53,16 @@ namespace GlitchyEditor
 		public SceneRenderer GameSceneRenderer {get; set;}
 		public SceneRenderer EditorSceneRenderer {get; set;}
 
+		private static Editor s_Instance;
+
+		public static Editor Instance => s_Instance;
+
 		/// Creates a new editor for the given world
 		public this(Scene scene, EditorContentManager contentManager)
 		{
+			Log.EngineLogger.AssertDebug(s_Instance == null, "Cannot create a second instance of a singleton.");
+			s_Instance = this;
+
 			_scene = scene;
 			_contentManager = contentManager;
 

GlitchyEditor/src/ImGuiExtension.bf

@@ -0,0 +1,33 @@
+using System;
+
+namespace ImGui;
+
+enum DragDropPayloadType
+{
+	case ContentBrowserItem;
+	case Entity;
+
+	public String GetName()
+	{
+		switch (this)
+		{
+		case .ContentBrowserItem:
+			return "CONTENT_BROWSER_ITEM";
+		case .Entity:
+			return "ENTITY";
+		}
+	}
+}
+
+extension ImGui
+{
+	public static Payload* AcceptDragDropPayload(DragDropPayloadType type, DragDropFlags flags = .None)
+	{
+		return AcceptDragDropPayload(type.GetName(), flags);
+	}
+
+	public static bool SetDragDropPayload(DragDropPayloadType type, void* data, size sz, Cond cond = .None)
+	{
+		return SetDragDropPayload(type.GetName(), data, sz, cond);
+	}
+}