Managing State

Abstract

In classic point-and-click adventure games, one of the most entertaining and challenging goals is to collect anything and everything that is not nailed down and then try to figure out where it needs to be used. To make things even more interesting, many games require you to combine inventory items before they will be able to perform the necessary task. It may be as mechanically logical as combining a hammerhead with a wooden handle to make a usable tool, or as challenging as adding the correct ingredients to a brew. In the former, you might consider the combination object a totally new object that needs to be activated in the scene. In the latter, however, you might need to change its virtual state each time an ingredient is added. Even something as simple as a door can have two states: open and closed. While some states, such as with the door, physically prevent access to a location or crucial object, others, such as a lock on the same door, have no physical manifestation. If the door’s state is locked, interaction with it might produce a rattle, but if its state is unlocked, it will open when picked, putting it into a third state, open. Once you consider adding save and restore functionality to the game, the need for a means to track state becomes even more important.