Add NPC and items walking.

game/ui/ui_9verbs/inventory/inventory_ui.tscn

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+[gd_scene load_steps=4 format=2]
+
+[ext_resource path="res://addons/escoria-core/game/scenes/inventory/inventory_ui.gd" type="Script" id=1]
+[ext_resource path="res://game/items/ESCORIA_ALL_ITEMS.tscn" type="PackedScene" id=2]
+[ext_resource path="res://game/ui/ui_9verbs/inventory/inventory_ui_container.gd" type="Script" id=3]
+
+[node name="inventory_ui" type="Control"]
+script = ExtResource( 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+items_container = NodePath("PanelContainer/ScrollContainer/GridContainer")
+
+[node name="PanelContainer" type="PanelContainer" parent="."]
+margin_right = 600.0
+margin_bottom = 175.0
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="ScrollContainer" type="ScrollContainer" parent="PanelContainer"]
+margin_left = 7.0
+margin_top = 7.0
+margin_right = 593.0
+margin_bottom = 168.0
+
+[node name="GridContainer" type="GridContainer" parent="PanelContainer/ScrollContainer"]
+margin_right = 586.0
+size_flags_horizontal = 3
+custom_constants/vseparation = 16
+custom_constants/hseparation = 16
+columns = 4
+script = ExtResource( 3 )
+
+[node name="ESCORIA_ALL_ITEMS" parent="." instance=ExtResource( 2 )]
+position = Vector2( 269.391, 275.003 )

game/ui/ui_9verbs/inventory/inventory_ui_container.gd

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+extends Control
+
+"""
+This script is totally user-defined. It does exactly what the user wants the 
+inventory to look like. It only requires 4 functions to be defined:
+	- is_empty() -> bool
+	- get_items() -> Array
+	- add_item(inventory_item : ESCInventoryItem)
+	- remove_item(inventory_item : ESCInventoryItem)
+The user is free to implement these methods the way s-he likes.
+"""
+
+var current_nodes_in_container = {}
+
+func is_empty() -> bool:
+	return get_child_count() > 0
+
+func get_items() -> Array:
+	return current_nodes_in_container.keys()
+
+func add_item(inventory_item : ESCInventoryItem):
+	var center_container = CenterContainer.new()
+	center_container.size_flags_horizontal = SIZE_EXPAND_FILL
+	center_container.connect("mouse_entered", inventory_item, "_on_inventory_item_mouse_enter")
+	center_container.connect("mouse_exited", inventory_item, "_on_inventory_item_mouse_exit")
+	center_container.connect("gui_input", self, "_on_gui_input", [inventory_item])
+	center_container.add_child(inventory_item)
+	add_child(center_container)
+	current_nodes_in_container[inventory_item] = center_container
+
+func remove_item(inventory_item : ESCInventoryItem):
+	var node_to_remove = current_nodes_in_container[inventory_item]
+	current_nodes_in_container.erase(node_to_remove)
+	node_to_remove.disconnect("mouse_entered", inventory_item, "_on_inventory_item_mouse_enter")
+	node_to_remove.disconnect("mouse_exited", inventory_item, "_on_inventory_item_mouse_exit")
+	node_to_remove.disconnect("pressed", self, "_on_gui_input")
+	remove_child(node_to_remove)
+	node_to_remove.queue_free()
+	
+func _on_gui_input(event : InputEvent, inventory_item : ESCInventoryItem):
+	if event is InputEventMouseButton and event.is_pressed():
+		inventory_item._on_inventory_item_pressed()