Implemented Entity and Component Drop-Targets and added Name property for entities

- Also fixed non generic GetComponent
- Use UUID as Drag-Drop value for entities
- Removed unused methods from ComponentEditWindow
- Started a marginally type-safe version of ImGui.Payload

GlitchyEditor/src/EditWindows/ComponentEditWindow.bf

@@ -568,174 +568,6 @@ namespace GlitchyEditor.EditWindows
 			ScriptEngine.ShowScriptEditor(entity, scriptComponent);
 		}
 
-
-		private static Entity? ShowEntitySelector()
-		{
-			static char8[128] entitySearch = .();
-
-			Entity? result = null;
-
-			if (ImGui.BeginPopup("ENTITY_SELECTOR"))
-			{
-				ImGui.TextUnformatted("Search:");
-				ImGui.SameLine();
-
-				if (ImGui.InputText("##entitySearcher", &entitySearch, (uint64)entitySearch.Count))
-				{
-
-				}
-
-				ImGui.EndPopup();
-			}
-
-			return result;
-		}
-
-		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 (entityId == UUID(0))
-				entityName.Set("None");
-			else 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))
-			{
-				if (fieldEntity case .Ok)
-					Editor.Instance.EntityHierarchyWindow.HighlightEntity(fieldEntity);
-			}
-
-			if (ImGui.BeginDragDropTarget())
-			{
-				ImGui.Payload* peekPayload = ImGui.AcceptDragDropPayload(.Entity, .AcceptPeekOnly);
-
-				bool allowDrop = false;
-
-				if (peekPayload != null)
-				{
-					Entity draggedEntity = *(Entity*)peekPayload.Data;
-
-					ScriptClass draggedScriptClass = ScriptEngine.Classes.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 Entity?  
-
-		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 (entityId == UUID(0))
-				entityName.Set("None");
-			else 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))
-			{
-				if (fieldEntity case .Ok)
-					Editor.Instance.EntityHierarchyWindow.HighlightEntity(fieldEntity);
-			}
-
-			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];
-
-					// For some reason we have to retrieve the MonoType like this. Using scriptField.GetMonoType() directly returns the wrong type...
-					MonoReflectionType* reflectionType = Mono.mono_type_get_object(ScriptEngine.[Friend]s_AppDomain, scriptField.GetMonoType());
-					MonoType* actualMonoType = Mono.mono_reflection_type_get_type(reflectionType);
-
-					// TODO: We shouldn't abuse the script glue like that.
-					// ScriptGlue should only be called by C#, not by Beef.
-					if (ScriptGlue.[Friend]s_HasComponentMethods.TryGetValue(actualMonoType, let has_component))
-					{
-						allowDrop = has_component(draggedEntity);
-					}
-					else
-					{
-						Log.EngineLogger.Warning($"No HasComponent-Function found for field {scriptField.Name}");
-						allowDrop = false;
-					}
-				}
-
-				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);

GlitchyEditor/src/EditWindows/EntityHierarchyWindow.bf

@@ -415,7 +415,8 @@ namespace GlitchyEditor.EditWindows
 			{
 				isDragged = true;
 
-				ImGui.SetDragDropPayload(.Entity, &tree.Value, sizeof(Entity));
+				UUID id = tree.Value.UUID;
+				ImGui.SetDragDropPayload(.Entity, &id, sizeof(UUID));
 
 				ImGui.Text(name);
 
@@ -464,13 +465,13 @@ namespace GlitchyEditor.EditWindows
 		{
 			if(ImGui.BeginDragDropTarget())
 			{
-				ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.Entity);
+				Payload<UUID>? payload = ImGui.AcceptDragDropPayload<UUID>(.Entity);
 
 				if(payload != null)
 				{
-					Log.ClientLogger.AssertDebug(payload.DataSize == sizeof(Entity));
+					UUID movedEntityId = payload->Data;
 
-					Entity movedEntity = *(Entity*)payload.Data;
+					Entity movedEntity = _editor.CurrentScene.GetEntityByID(movedEntityId);
 
 					bool dropLegal = true;
 
@@ -556,13 +557,13 @@ namespace GlitchyEditor.EditWindows
 				{
 					if(ImGui.BeginDragDropTarget())
 					{
-						ImGui.Payload* payload = ImGui.AcceptDragDropPayload(.Entity);
+						Payload<UUID>? payload = ImGui.AcceptDragDropPayload<UUID>(.Entity);
 
 						if(payload != null)
 						{
-							Log.ClientLogger.AssertDebug(payload.DataSize == sizeof(Entity));
+							UUID movedEntityId = payload->Data;
 							
-							Entity movedEntity = *(Entity*)payload.Data;
+							Entity movedEntity = _editor.CurrentScene.GetEntityByID(movedEntityId);
 
 							// Also mark transform as dirty
 							var transformComponent = movedEntity.GetComponent<TransformComponent>();

GlitchyEditor/src/ImGuiExtension.bf

@@ -21,6 +21,11 @@ enum DragDropPayloadType
 
 extension ImGui
 {
+	public static Payload<T>? AcceptDragDropPayload<T>(ImGui.DragDropPayloadType type, DragDropFlags flags = .None) where T : struct
+	{
+		return AcceptDragDropPayload<T>(type.GetName(), flags);
+	}
+
 	public static Payload* AcceptDragDropPayload(DragDropPayloadType type, DragDropFlags flags = .None)
 	{
 		return AcceptDragDropPayload(type.GetName(), flags);

GlitchyEngine/src/ImGui/ImGuiExtension.bf

@@ -16,6 +16,15 @@ namespace ImGui
 {
 	using internal GlitchyEngine.Math;
 
+	struct Payload<T> where T : struct
+	{
+		public ImGui.Payload* Payload;
+
+		public T Data => *(T*)Payload.Data;
+
+		public static ImGui.Payload* operator ->(Payload<T> self) => self.Payload;
+	}
+
 	extension ImGui
 	{
 		extension Vec2
@@ -30,6 +39,21 @@ namespace ImGui
 			public static explicit operator Vec4(float4 v) => .(v.X, v.Y, v.Z, v.W);
 		}
 
+		public static Payload<T>? AcceptDragDropPayload<T>(char8* type, DragDropFlags flags = .None) where T : struct
+		{
+			ImGui.Payload* payload = ImGui.AcceptDragDropPayload(type, flags);
+
+			if (payload == null)
+				return null;
+
+			Log.ClientLogger.AssertDebug(payload.DataSize >= sizeof(T));
+
+			var typedPayload = Payload<T>();
+			typedPayload.Payload = payload;
+
+			return typedPayload;
+		}
+
 		/*public static bool IsItemJustDeactivated()
 		{
 		    return IsItemDeactivatedAfterEdit();

GlitchyEngine/src/Scripting/ScriptGlue.bf

@@ -301,6 +301,28 @@ static class ScriptGlue
 		}
 	}
 	
+	[RegisterCall("ScriptGlue::Entity_GetName")]
+    static MonoString* Entity_GetName(UUID entityId)
+	{
+		Entity entity = ScriptEngine.Context.GetEntityByID(entityId);
+
+		MonoString* name = Mono.mono_string_new_len(ScriptEngine.[Friend]s_AppDomain, entity.Name.Ptr, (.)entity.Name.Length);
+
+		return name;
+	}
+    
+	[RegisterCall("ScriptGlue::Entity_SetName")]
+    static void Entity_SetName(UUID entityId, MonoString* name)
+	{		
+		Entity entity = ScriptEngine.Context.GetEntityByID(entityId);
+
+		char8* rawName = Mono.mono_string_to_utf8(name);
+
+		entity.Name = StringView(rawName);
+
+		Mono.mono_free(rawName);
+	}
+
 #endregion
 
 #region TransformComponent

GlitchyEngineHelper/src/Mono/Mono.bf

@@ -76,6 +76,9 @@ static class Mono
 	[LinkName(.C)]
 	public static extern MonoString* mono_string_new(MonoDomain* domain, char8* text);
 	
+	[LinkName(.C)]
+	public static extern MonoString* mono_string_new_len(MonoDomain* domain, char8* text, uint32 length);
+
 	[LinkName(.C)]
 	public static extern MonoDomain* mono_domain_get();
 

ScriptCore/Editor/EntityEditor.cs

@@ -272,13 +272,11 @@ internal class EntityEditor
         }
         else if (fieldType.IsSubclassOf(typeof(Entity)) || fieldType == typeof(Entity))
         {
-            // TODO: Show entity drop target
+            newValue = ShowEntityDropTarget(fieldName, fieldType, reference);
-            ImGui.Text($"{fieldName} Entity ({fieldType.Name})");
         }
         else if (fieldType.IsSubclassOf(typeof(Component)))
         {
-            // TODO: Show component drop target
+            newValue = ShowComponentDropTarget(fieldName, fieldType, reference);
-            ImGui.Text($"{fieldName} Component ({fieldType.Name})");
         }
         else if (fieldType == typeof(string))
         {
@@ -338,6 +336,171 @@ internal class EntityEditor
         return newValue;
     }
 
+    private static object ShowComponentDropTarget(string fieldName, Type fieldType, object currentValue)
+    {
+        object newValue = DidNotChange;
+        
+        ImGui.Text($"{fieldName}: ");
+        ImGui.SameLine();
+
+        Component component = currentValue as Component;
+
+        string entityName = "None";
+
+        if (component != null)
+        {
+            entityName = component.Entity.Name;
+        }
+        
+        Type actualType = component?.GetType();
+
+        entityName += $" ({(actualType ?? fieldType).Name})";
+        
+        if (ImGui.Button(entityName))
+        {
+            if (component?.Entity != null)
+            {
+                // TODO: Hightlight Entity in hierarchy
+                // TODO: Highlight Component in editor
+            }
+        }
+
+        if (ImGui.BeginDragDropTarget())
+        {
+            ImGuiPayloadPtr peekPayload = ImGui.AcceptDragDropPayload("ENTITY", ImGuiDragDropFlags.AcceptPeekOnly);
+
+            bool allowDrop = false;
+            
+            unsafe
+            {
+                if (peekPayload.NativePtr != null)
+                {
+                    UUID draggedId = *(UUID*)peekPayload.Data;
+
+                    Entity draggedEntity = new Entity(draggedId);
+
+                    allowDrop = draggedEntity.HasComponent(fieldType);
+                }
+
+                if (allowDrop)
+                {
+                    ImGuiPayloadPtr payload = ImGui.AcceptDragDropPayload("ENTITY");
+                    
+                    if (payload.NativePtr != null)
+                    {
+                        UUID droppedId = *(UUID*)payload.Data;
+                        
+                        Entity draggedEntity = new Entity(droppedId);
+
+                        try
+                        {
+                            newValue = draggedEntity.GetComponent(fieldType);
+                        }
+                        catch (Exception e)
+                        {
+                            Log.Error(e);
+                        }
+                    }
+                }
+            }
+
+            ImGui.EndDragDropTarget();
+        }
+
+        return newValue;
+    }
+
+    private static object ShowEntityDropTarget(string fieldName, Type fieldType, object currentValue)
+    {
+        object newValue = DidNotChange;
+
+        ImGui.Text($"{fieldName}: ");
+        ImGui.SameLine();
+
+        string entityName = "None";
+        
+        Entity entity = currentValue as Entity;
+
+        if (entity != null)
+        {
+            entityName = entity.Name;
+        }
+
+        Type actualType = entity?.GetType();
+
+        entityName += $" ({(actualType ?? fieldType).Name})";
+
+        if (ImGui.Button(entityName))
+        {
+            if (entity != null)
+            {
+                // TODO: Hightlight Entity in hierarchy
+            }
+        }
+
+        if (ImGui.BeginDragDropTarget())
+        {
+            ImGuiPayloadPtr peekPayload = ImGui.AcceptDragDropPayload("ENTITY", ImGuiDragDropFlags.AcceptPeekOnly);
+
+            bool allowDrop = false;
+            
+            unsafe
+            {
+                if (peekPayload.NativePtr != null)
+                {
+                    UUID draggedId = *(UUID*)peekPayload.Data;
+
+                    Entity draggedEntity = new Entity(draggedId);
+
+                    // TODO: Check if entity is valid?
+
+                    if (fieldType == typeof(Entity))
+                    {
+                        allowDrop = true;
+                    }
+                    else
+                    {
+                        Entity scriptInstance = Entity.GetScriptReference(draggedId, typeof(Entity));
+
+                        allowDrop = fieldType.IsInstanceOfType(scriptInstance);
+                    }
+                }
+
+                if (allowDrop)
+                {
+                    ImGuiPayloadPtr payload = ImGui.AcceptDragDropPayload("ENTITY");
+                    
+                    if (payload.NativePtr != null)
+                    {
+                        UUID droppedId = *(UUID*)payload.Data;
+                        
+                        if (fieldType == typeof(Entity))
+                        {
+                            newValue = new Entity(droppedId);
+                        }
+                        else
+                        {
+                            newValue = Entity.GetScriptReference(droppedId, typeof(Entity));
+                        }
+                    }
+                }
+            }
+
+            ImGui.EndDragDropTarget();
+        }
+
+        ImGui.SameLine();
+
+        if (ImGui.Button("..."))
+        {
+            // TODO: Show entity selector
+        }
+
+        ImGuiExtension.AttachTooltip("Search entity...");
+
+        return newValue;
+    }
+
     private static object ShowStringEditor(object reference, Type fieldType, string fieldName, IEnumerable<Attribute> attributes)
     {
         object newValue = DidNotChange;

ScriptCore/Entity.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Diagnostics;
+using System.Reflection;
 using System.Runtime.CompilerServices;
 using GlitchyEngine.Core;
 using GlitchyEngine.Extensions;
@@ -11,6 +12,15 @@ namespace GlitchyEngine;
 /// </summary>
 public class Entity : EngineObject
 {
+    /// <summary>
+    /// Gets or sets the name of the entity.
+    /// </summary>
+    public string Name
+    {
+        get => ScriptGlue.Entity_GetName(_uuid);
+        set => ScriptGlue.Entity_SetName(_uuid, value);
+    }
+
     /// <summary>
     /// Only to be called by the engine. Don't call this constructor yourself, it will not result in a valid entity.
     /// If you want to create a new entity use <see cref="Entity(string)"/> or <see cref="Entity(string, Type[])"/>
@@ -102,7 +112,12 @@ public class Entity : EngineObject
         
         if (HasComponent(componentType))
         {
-            return Activator.CreateInstance(componentType, true, _uuid) as Component;
+            Component component = Activator.CreateInstance(componentType, true) as Component;
+
+            if (component != null)
+                component._uuid = _uuid;
+
+            return component;
         }
 
         return null;
@@ -312,13 +327,13 @@ public class Entity : EngineObject
     /// <param name="id">The id of the entity whose script instance shall be returned.</param>
     /// <param name="type">The type of the script.</param>
     /// <returns>The script instance or null.</returns>
-    internal static object GetScriptReference(UUID id, Type type)
+    internal static Entity GetScriptReference(UUID id, Type type)
     {
-        Debug.Assert(type.IsSubclassOf(typeof(Entity)));
+        Debug.Assert(typeof(Entity).IsAssignableFrom(type));
 
         ScriptGlue.Entity_GetScriptInstance(id, out object scriptInstance);
 
-        return scriptInstance;
+        return scriptInstance as Entity;
     }
 
     /// <summary>

ScriptCore/ScriptGlue.cs

@@ -46,6 +46,12 @@ internal static class ScriptGlue
     [MethodImpl(MethodImplOptions.InternalCall)]
     internal static extern void Entity_RemoveScript(UUID entityId);
     
+    [MethodImpl(MethodImplOptions.InternalCall)]
+    public static extern string Entity_GetName(UUID entityId);
+    
+    [MethodImpl(MethodImplOptions.InternalCall)]
+    public static extern string Entity_SetName(UUID entityId, string name);
+    
 #endregion Entity
 
 #region TransformComponent