Cold Take #38 - Avoid State Toggles

Almost everything players do in RTS is done by issuing direct commands or by toggling states. Direct commands give units a temporary goal, and include classics such as "move to this location" or "shoot at this enemy until it dies". State toggles make more permanent changes to how a unit behaves, at least until the state is toggled back. Examples include auto-cast toggles, toggleable abilities, and the stance and formation buttons used in the Age of Empires series. Toggles can be fine when used sparingly, but Zero-K did the opposite, to the point that we might have more than any other RTS. The upside is that we learned a lot about how and why to avoid state toggles.

The allure of state toggles is that they seem to epitomise the idea of Fight Your Opponent, Not The UI . Players should be able to express their wishes with minimal commands; in Warcraft III you want a Priest to use its extra mana to heal, then being able to tell it to automatically heal implements that desire with one click. In Zero-K, players often want units to keep the enemy at their maximum range, which is much easier to do with a state toggle than a constant stream of redundant move commands. We can also think of state toggles in terms of the demarcation between a unit's abilities and its behaviours. For example, shooting feels like behaviour, so it makes sense to have a Hold Fire state toggle.

There are broadly two types of state toggle: ability toggles and behaviour toggles. This is a useful distinction despite the fact that, at a fundamental level, everything a unit can do is an ability, and every different way it can choose to do it is a behaviour. In practise there is a often clear difference between controlling a specific ability or generic behaviour, although some toggles end up in between.

Ability toggles are found in many games and include cloaking, burrowing and deploying. To be precise, we can define an ability toggle as a state toggle that is a necessary part of using an ability. You cannot set your tanks to siege mode without touching the siege mode toggle, but you can cast spells in Warcraft III without toggling auto-cast, so auto-cast is a behaviour toggle. On the topic of Warcraft and Starcraft, their Hold Position command is not a toggle at all since it has to be re-issued each time you want your units to stay still.

Total Annihilation was one of the earliest games which put behaviour toggles such as Hold Position front-and-centre. Everything that moves had a move toggle with three states: Hold Position, Manoeuvre and Roam, with the latter two effectively being "move around a bit" and "move around a lot". Everything with a weapon also had a fire state with three states: Hold Fire, Return Fire and Fire At Will, with return fire causing units to shoot back after they take damage. Total Annihilation also had ability toggles, such as cloaking and the ability to turn Solar Collectors on or off.

The problem with state toggles is that they are fiddly and are, for the most part, the least satisfying way to control units. Issuing orders, say to set up a flank or to unleash an ability on a group of enemies, is much more fun than fiddling around with buttons tucked into the corner of the interface. Many state toggles have subtle effects, which makes it hard for players to see that their actions had any impact. Seeing the states of