Add test for gdpd initialisation

core/IvmiScene.gd

@@ -78,6 +78,7 @@ func _ready():
 	# PureData mode
 	if _pd_mode==PdMode.LIBPD :
 		var gdpdir = DirAccess.open("res://addons/gdpd")
+		var gdpdok : bool = false
 		if gdpdir :
 			_gdpd = ClassDB.instantiate("GdPd")
 			add_child(_gdpd)
@@ -85,6 +86,7 @@ func _ready():
 				# Get all input and output devices
 				var inps = _gdpd.get_available_input_devices()
 				var outs = _gdpd.get_available_output_devices()
+				if inps.size()>0 and outs.size()>0 :
 					# Initialise the first ones
 					_gdpd.init_devices(inps[0], outs[0])
 					# Open patch
@@ -92,7 +94,9 @@ func _ready():
 					var patch_name = global_patch.split("/")[-1]
 					var patch_dir = global_patch.trim_suffix(patch_name)
 					_gdpd.openfile(patch_name, patch_dir)
-		else :
+					gdpdok=true
+		
+		if not gdpdok :
 			print("IVMI : Could not load gdpd addon")
 			_pd_mode=PdMode.OSC