divers changements pour la sortie du second proto

* ajout du panneau solaire #54
* ajout d'un tutoriel #53
* equilibrage du jeu #73
* ajout d'un son pour l'annonce

entities/player/scripts/player.gd

@@ -124,18 +124,20 @@ func try_move(move_to : Vector2):
 	instruction = MoveInstruction.new(move_to)
 
 func pick_item(item : Item) -> Item:
-	inventory.add_item(item)
-	var currentItem : Item = inventory.get_item()
-	var itemSwapped : bool = false
 	play_sfx("pick")
-	if !itemSwapped:
-		currentItem = null
-	return currentItem
+	if inventory.length() >= inventory.size:
+		var currentItem : Item = inventory.get_item()
+		inventory.set_item(item, inventory.current_item_ind)
+		return currentItem
+	else :
+		inventory.add_item(item)
+		return null
 
 func drop_item():
 	var item_to_drop = inventory.pop_item()
-	planet.drop_item(item_to_drop, global_position)
-	play_sfx("drop")
+	if item_to_drop:
+		planet.drop_item(item_to_drop, global_position)
+		play_sfx("drop")
 
 func delete_item(item: Item):
 	inventory.remove_item(item)