Why Games are Terrible at Water

Water is why you’re alive right now. It’s one of the major prerequisites for both creating and sustaining life. But while oceans cover 71% over of our planet, water often plays a peripheral role in games, secondary to any actions on land. This is partially because water poses unique challenges both to physics engines, with the result being that the medium as a whole may be ill equipped to translate an underwater experience. However, enormous opportunities exist for developers who can get creative about braving the depths — and they might help save the planet.

All gameplay systems are stylized to a certain extent. We understand that we’re not firing a real gun or driving a real car when we’re playing a game, and expect developers to cut corners for the sake of gameplay. But even so, developers take such liberties with water it tends to fray the suspension of disbelief. Realistically, humans are not aquatic creatures. Water blurs our vision and our hands and feet are poor substitutes for fins. We’re so ill-equipped for underwater environments that we need a life support system to survive there for more than a few minutes. Apart from easier access, underwater might as well be outer space. Most games flat-out ignore these facts for playability’s sake. Characters see perfectly underwater. Their lungs burn air at the same rate swimming as they do at rest. They plunge down like Olympians, and don’t seem naturally buoyant like real human bodies. But most of that you can chalk up to playability. It’s physics engines – so precise above the surface – that seem way off.

Partially this has to do with the fact that water’s harder to program than air. Fluid dynamics are notoriously difficult, even for aspiring engineers and physics students, and the fact that it’s a denser medium than air upends most physics engines. On land, you can generally assume that gravity affects objects universally – unless it’s a balloon, when you drop something, it’s going to travel downward. But water’s density means that things with greater density are going to sink while things with lighter density will float. This is especially difficult to program when it comes to humans, since even the amount of air in a person’s lungs can change their buoyancy. To counteract buoyancy while snorkeling or skin-diving means fighting your way downward while exhaling. SCUBA divers, on the other hand, descend, ascend, and maintain neutral buoyancy with weight belts and a Buoyancy Control Device that inflates or deflates using compressed air from their tank. Apart from simulators like Infinite SCUBA, games tend to ignore these physics and, as a result, there’s a feeling of wrongness that accompanies going underwater.

Things aren’t much better on the surface, either. Simulating waves seems beyond most engines, since the processing power you’d need to create them is immense. Unlike the solid objects game engines are good at, water flows and changes in a way that developers can animate but often not actually model. Take waves, for example. Most games don’t bother to create waves, but those that do generally settle for a rolling motion. Witness the ship graveyard in Uncharted 3, for instance, where the sea laps by like it’s a blanket someone’s shaking out. Or Assassin’s Creed 4 which had dynamic rolling waves at sea but no surf to speak of. This programming isn’t wrong exactly. It’s a common misconception that waves are made up of water. In fact, waves are simply energy traveling through water and affecting it as it passes through. Much like a blanket’s fabric doesn’t travel forward when you shake it, water mostly stays where it is as the wave affects it and moves on, so in that sense these game waves are accurate. But the problem is that most video game waves lack lateral energy – that they move you up and down but not much horizontally – and that they never break.

In brief, waves break onshore when the bottom of the wave slows down due to friction on reef or sand and the top of the wave overtakes it, spilling over the top. A similar thing can happen in the open ocean when a wave becomes large enough that the wave’s length can’t sustain its height. The problem is that this action changes the wave from the simple crest-and-trough formation most engines can handle, to a more complex form with different parts moving at different speeds. While some games like Grand Theft Auto V have created impressive visual illusions to make you think their waves break – Rockstar flecked the top of their “breaking” waves with flat whitewater texture, but their physics don’t change – it’ll be quite awhile before physics engines allow players to shoot the curl or barrel ride a truly dynamic wave.

In short, water’s a hard trick for game programmers because a game with realistic above water, surface, and underwater play would need to have two or even three physics engines stacked on top of one another, each with its own laws. And given that water’s often considered a tertiary feature at best, there hasn’t been much development money invested in physics engines to handle water’s unique environment. Developers tend to treat swimming as flying, but slower. In reality being underwater is a full-sensory experience that affords you 360 degrees of movement and makes you feel the ocean’s energy in a way you never feel air — and that’s almost impossible to translate in a medium as physically detached as videogames. And it isn’t just about waves, either. Developers are currently unable to create currents and rip currents, simulate undertow, have water react to shore conditions, support much aquatic life or even show the tidal cycle. Unlike the living system that supports our planet, video game oceans seem like dead space.

But water presents huge gameplay possibilities, and there are steps developers can take to deliver better underwater gameplay. Hydrophobia may have landed hard, but the HydroEngine managed to create fluid dynamics that were far more convincing than most games. (HydroEngine is probably for sale in Dark Energy Digital’s bankruptcy proceedings and it works with the Havok Engine, HINT HINT.) While GTA V‘s breaking waves amounted to a visual trick, they remained convincing at a distance. And the aforementioned indie game Infinite SCUBA contains the most faithful buoyancy physics and equipment I’ve seen so far. Assassin’s Creed 4‘s diving sections, by contrast, fell prey to many of the old problems with video game swimming, but the currents that sucked Edward through underwater tunnels got closer to that tactile sense of fluid dynamics than any other game I’ve played.

But for a smart designer who’s willing to get creative, water opens a whole new medium to play with. Water levels usually serve to obscure hidden items or as breath-hold obstacle courses, but they could be so much more. Underwater action scenes ala Thunderball could be a huge customer draw if done right (and by “if done right” I mean “without the restrictive linearity Call of Duty: Ghosts employed“). Indeed, underwater action scenes could feel tactical and visceral if studios paid more attention to the technical aspects of diving. Imagine a game where your air is running out, and you have to ambush other divers and steal their tanks to survive — that I would play. If we could marry the impressive visuals in Call of Duty: Ghosts‘s SCUBA sections with the frantic moment in Far Cry 3 where the player had to escape a ship by snagging air tanks floating in the wreckage, we’d be most of the way there.

Underwater settings also have unrealized potential as an exploration environment. There is some movement in this direction – Infinite SCUBA allows the player to dive a WWII wreck, find artifacts and identify coral and fish species – and Abzu looks like it will take this direction as well. Endless Ocean and its sequel promised this, but failed to make it engaging enough for wide appeal. But as one of the great unexplored environments on earth, the ocean provides a perfect setting for finding lost things or unknown creatures. And if a developers got creative, a game that tackled the ocean as its primary environment could do amazing things in this vein – picture an exploration/horror game set in the deep sea.

Apart from the vast potential in the setting, there’s another reason developers should pay attention to our watery world. To be frank, the ocean is the world’s circulatory system, mankind’s largest transportation grid for goods, humanity’s refrigerator and – increasingly – our trash dump. It also produces the majority of our oxygen. If you see some conflict in those purposes, you’re not the only one. As global warming threatens important ocean characteristics like temperature, salinity and thermohaline circulation, scientists are expressing concern about ocean health. But the fact is that though the ocean affects everyone on Earth, very few people will regularly connect with the ocean as an environment – and fewer will spend more than a few hours in their lifetime beneath the surface. For most people, the ocean is out of sight, out of mind.

But games can place us in an unfamiliar setting and convey its reality. They have the potential to let people who live thousands of miles from the ocean engage with underwater environments and make them tangible. Even if that engagement isn’t focused on environmentalism, introducing the ocean as a living thing — not a dead zone — could bring players closer to understanding its importance.

Developers are doing the best they can to convey the physics of water, but significant technical barriers remain. However, for an enterprising developer who’s willing to throw their weight behind creating great environments, the sea offers a fitting playground for adventure, education and human curiosity.