You’re a special agent behind enemy lines. Tucked into a dark bunker, your heart races as you hear the rapidly approaching footsteps of a hostile guard. You cock your pistol, careful to not alert the guard. As he comes around the corner you hold your breath in anticipation. You raise the gun, lining up the sights with his head, but when you pull the trigger, he doesn’t react as you’d expect. Instead of falling backward, he awkwardly collapses towards you, his arm passing through a nearby wall. You’re immediately ripped from the otherwise immersive experience and remember you were just playing a computer game.

Physics are an important factor in creating an immersive experience in video games. All the most memorable games have found ways of overcoming the technological constraints of their time to create experiences that kept players coming back. When physics are done wrong, it can be disastrous. Bargain bins are littered with games that invested more in movie licenses or flashy graphics than they did into tweaking the physics to make the gameplay enjoyable. But when done right, the results are powerful and memorable.

To understand the current climate of game physics, one must first understand a brief history of pivotal games physics technologies and how they have influenced other game developers, as well as current technologies that are still in the process of being introduced.

The Golden Era: 1962-1981
Even before the advanced 3D graphics of current generation video games, physics played an important role in the game experience. One of the earliest examples of successful game physics is in Spacewar, released in 1962. In Spacewar, players control spaceships that fire bullets and missiles at one another while avoiding being shot or colliding with a star. The physics in that game calculates a gravitational pull that arcs the trajectory of bullet fire, and pulls ships toward them. This gives the game a unique feel that even later more technologically advanced games like Asteroids can’t reproduce.

A decade later Pong brought games to mainstream audiences. While Pong had primitive gameplay -- two paddles knocking a ball back and forth -- it’s based on a simple physics calculation that determines where on the paddle the ball will hit and bounces it back at the appropriate angle. Atari knew it was on to something good and used the same game mechanic in a single-player version, Breakout. Instead of trying to beat an opponent, the player tries to destroy stationary bricks.

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