Can now round-trip a torch from loot to inventory and back.

gui/loot_ui.cpp

@@ -78,10 +78,25 @@ namespace gui {
         auto& sprite = $level.world->get<components::Sprite>(item);
         guecs::GrabSource grabber{sprite.name};
         $gui.set_init<guecs::Sprite>(id, grabber);
+      } else {
+        $gui.set<guecs::DropTarget>(id, {
+           [&, id]() -> bool { return place_slot(id); }
+        });
       }
     }
   }
 
+  bool LootUI::place_slot(DinkyECS::Entity id) {
+    if(contents.size() < INV_SLOTS && !contents.contains(id)) {
+      contents.try_emplace(id, $selected_entity);
+      dbc::log(fmt::format("adding entity {}", id));
+      update();
+      return true;
+    } else {
+      return false;
+    }
+  }
+
   bool LootUI::has_grab_source(DinkyECS::Entity gui_id) {
     return $gui.has<guecs::Sprite>(gui_id);
   }
@@ -109,4 +124,19 @@ namespace gui {
   guecs::DropTarget& LootUI::get_drop_target(DinkyECS::Entity gui_id) {
     return $gui.get<guecs::DropTarget>(gui_id);
   }
+
+  void LootUI::begin_drop(DinkyECS::Entity world_entity) {
+    dbc::log("begin the loot drop");
+    $selected_entity = world_entity;
+  }
+
+  bool LootUI::commit_drop(DinkyECS::Entity gui_id) {
+    if($gui.has<guecs::DropTarget>(gui_id)) {
+      auto& drop = get_drop_target(gui_id);
+      return drop.commit();
+    } else {
+      // NOTE: I think I need to cancel the drop or something?
+      return false;
+    }
+  }
 }