Wraparound, in video games, is when an object moves off of one side of the screen and reappears on the other. In Asteroids for example, the player's ship flies off of the right side of the screen, then continues on the left side with the same velocity. This is referred to as wraparound, since the top and bottom of the screen wrap around to meet, as do the left and right sides (this is topologically equivalent to a Euclidean 2-torus).[1]
Some games wrap around in certain directions but not others, such as games of the Civilization series that wrap left to right, but the top and bottom remain edges, representing the North and South Pole (topologically equivalent to a cylinder). In some games, such as Asteroids, there is no boundary and objects can travel over any part of the screen edge and reappear on the other side.[2] Others such as Pac-Man, Wizard of Wor, and some games in the Bomberman series, have a boundary surrounding most of the playing area but have few paths connecting the left side to the right, or the top to the bottom, that characters can travel on. Wraparound can also apply to scrolling games such as Defender, where the player can infinitely fly in one direction because the horizontal extents of the landscape are connected.
The concept of wraparound originated in the early days of video games when hardware limitations imposed constraints on the size of game worlds. Instead of creating expansive environments that required significant memory or processing power, developers utilized wraparound to simulate continuous gameplay on limited hardware. By wrapping the game space, players could move seamlessly from one edge of the screen to the other, creating a sense of exploration and openness.
Wraparound is most commonly seen in games with horizontal or vertical scrolling. In horizontal wraparound, when the player or game objects reach one edge of the screen, they appear on the opposite side, allowing continuous movement. Vertical wraparound functions similarly but wraps objects between the top and bottom of the screen. Some games even incorporate diagonal wraparound, where movement from one corner of the screen wraps to the opposite corner.
Numerous classic and contemporary video games have employed wraparound mechanics. Here are a few notable examples:
1962's Spacewar! has a wraparound playfield,[3] as does the first commercial arcade video game, Computer Space (1971). Wraparound was common in games throughout the 1970s and early 1980s, including Space Race (1973), Combat (1977), Asteroids (1979), and Star Castle (1980).[1] Surround (1977) for the Atari 2600 has a gameplay option called "wraparound" in the manual.[4]