Drew Gardner article from the book "Gamers"

Writers, Artists, and Programmers on the Pleasures of Pixels
Edited by Shanna Compton

Download a PDF (302 KB) of Drew Gardner's article from the book "Gamers".

Coin-Op Physics: A Vector-Graphics Retrospective

by Drew Gardner

Jump to the section about Gravitar

In the mid-1970s several companies began putting coin-ops in the lobbies of restaurants, hoping that children would fill them with their parents' quarters while the food was being cooked. I was happy to oblige in this respect. The games immediately drew me in with simple but beautiful flashing shapes and lights, fascinating controllers, and richly detailed fantasy art on the cabinets.

The idea of feeding quarters into a machine to engage interactively in some excitement, fun and time wasting was a no-brainer. The precedent was pinball and skee-ball, which I eagerly played every summer at the Jersey shore. Skeeball was a bowling game where the ball jumped up a ramp at the last second and landed in variously scored pockets. Tickets were then given to redeem valueless but appealing prizes. The real appeal was not in acquiring the prizes, but in the feeling of having generated value with one's own skill to get them -- a feeling not often accessible to children. The tone set in these skee ball/pinball arcades was similar to what I would experience later as a young teenager in video game arcades during the coin-op heyday in the early 1980s -- a chance to explore different games and try out one's skill in an adult-free darkened space with a slightly sleazy vibe that involved competition, vagrancy, and truancy etc., all appealing qualities to any self-respecting eleven year old boy.

The first video game I remember playing in one of these restaurant lobbies in the mid-late 1970s was Scott Bristow's Tank, 1975, a simple black and white game that featured the first use of ROM memory to store graphical data. This allowed the images in the game to have just enough detail to represent objects, not just the rectangles and lines that appeared in Pong. Tank was a two player duel-type game with a top-down perspective where the opponents would drive around a maze-like screen peppered with barricades, avoiding mines, shooting each other and trying to avoid being shot. The ultimate goal was racking up enough points within a set time limit to win the game. More quarters bought more time.

Tank was produced at a time when the processing power of affordable computers was not advanced enough to produce enemy AI. Like Pong, the computer in Tank provided the interface and game parameters, but the competition had to come from another human. Winning on points was certainly important in this game, but more important was entering the space of the game, developing the skills needed for controlling the little square globs of light, and of course the delights of destroying my sister's tank.

I would soon learn that there were other pleasures to be gotten from video games besides destroying my sibling's military equipment. It turned out that the laws of Sir. Isaac Newton could be fun.

The first coin-op game I recall playing by myself against the computer was another Atari game called Stunt Cycle, where the player controlled an Evel Knievel-type character and jumped over busses. The idea of finding excitement by jumping over things with a two-wheeled vehicle was a concept I was already familiar with growing up in suburban New Jersey. Inspired by Knievel, my friends and I had spent hours rigging ramps from plywood and cinderblocks and jumping our bicycles over garbage cans, flaming scrapwood, and each other. This was our way of playing around with Newtonian physics.

The theme, controller and cabinet art of Stunt Cycle drew me to the game, but it was the game play and physics engine that kept me there. Tank was fun and diverting, but Stunt Cycle was addictively fun. The controller for the game was a realistic-looking motorcycle handlebar that featured a rotating grip for acceleration and a brake. These were the only two inputs. Adjusting the motorcycles speed based on accelerating force, friction, inertia and time was the key to successfully jumping the buses and landing on the opposite ramp without crashing. Busses would be added as the player advanced. My absorption in the game came from the learning curve involved in gaining control of these simulated aspects of physics. It was about learning skills necessary for successfully interacting with the computer simulation, which was based on mathematical expressions of real world physics under the likewise simulated game-danger of bodily harm. It was thrilling. Modern racing games with complex physics engines are the descendants of Stunt Cycle.

The games I would become most involved with over the next few years, as arcade gaming became more and more popular, would combine the basic elements from Tank and Stunt Cycle -- simulated gravity/inertia/momentum, and shooting stuff.

Games based on computer simulation of the properties of physics have a much older history than most players are aware of. Tank was basically a land-based version of Steve Russell's Space War, a game that preceded it by twelve years. Space War, 1962, is considered to be the first video game, along with William Higinbotham's Tennis for Two, 1958. Inspired by the space opera fiction of E. E. "Doc" Smith, Space War, like Tank, involved two-player, two-object combat, but in outer space. The ships battled in around a central sun with gravity. The challenge was to duel while controlling the direction and speed of one's ship in the vacuum of space while avoiding being sucked in by the sun's gravity or shot by the other player.

Space War was programmed as a demonstration for the room-filling DEC PDP-1 computer at MIT, long before it occurred to anyone to try to make money on video games. Had the PDP-1 been marketed as a home gaming system at the time, it would have retailed for $120,000. The game spread quickly through any university or research facility that could afford the computer. It was the first shareware gaming hit -- shared via punchcards. It later came with the computer. The display of PDP-1 had been a modified oscilloscope. This produced a line-based, or vector graphics. Vector graphics systems would later reappear in the arcade game heyday of the late 1970s and early 1980s. This display technology, which facilitated some of most artistically distinct arcade games ever produced, had its origin in military radar display technology used in World War II, re-appropriated for the purpose of generating adolescent fun. A descendant of this graphics format is still in everyday use today in the form of Acrobat files.

Vector graphics games were basically line art, rather than continuous tone art, or raster. The art in vector games is drawing rather than painting. This graphics system allows for much more rapid animation and manipulation of the objects being represented, and the glowing segments have a very particular look -- thin white undulating lines in reversal against a black background. Because these graphics were based on straight line sections assembled from plotted points, the objects used in the vector games tended to be composed of basic art forms -- squares, triangles and rhomboids assembled together to form objects. By the late 1970s, affordable technology capable of rendering vector graphics had caught up to the PDP-1. Some of the best designs in early videos games like, Asteriods, Tempest, and Battlezone used this system.

The first a vector graphics game I encountered as a kid was Larry Rosenthal's Space Wars, a 1977 Cinematronics game. It was the first commercially successful arcade version of Steve Russell's original Space War. My sister and I spent hours battling it out in Space Wars. The black and white graphics, using Larry Rosenthal's Vectorbeam system, were spare but beautiful, mostly negative space with objects composed of small, brightly undulating lines. The five-button controls were Rotate Left, Rotate Right, Thrust, Fire and Hyperspace. Like Russell's game, the space of the game was finite but continuous, with the ships disappearing from one of the edges of the screen to reappear on the opposite edge. The occasional asteroid would streak past, possible the inspiration for a later game based on similar parameters -- Asteroids. Space War had a number of improvements over the original -- smoother game play, crisper and more detailed graphics, several difficulty settings and the ability to inflict partial damage to one's opponent. It was possible to blow half of a ship away, leaving the player spinning around with a single engine, disabled, but still able to play. The cabinet was massive, and of all arcade cabinets, the most reminiscent of the vending machines they seemed to have be based on.

Tom Skelly's Rip Off (1979) was a Cinematronics game that took the Tank model of top-down rotate/move/shoot and transformed it from a duel into the first collaborative video game. Two people played against computer controlled AI. The object was to protect a central stash of undulating triangular fuel canisters from pirate tanks who would try to steal them. These pirate tanks used some of first AI ever in a video game. They would act according to independent "goals," simple rule-sets that would dictate their individual behavior. When several pirate tanks appeared together this was know as swarming. The game design and black and white vector graphics of Rip Off were not particularly unusual, but this swarming enemy behavior was something I never seen before. The tanks didn't follow scripted paths. They moved in graceful, unpredictable, and purposeful ways. They seemed alive. It was possible to play the game individually, but it was most interesting when two people joined forces and developed strategies for defending their fuel. Cinematronics created several different vector games with similar parameters and feel, including Armor Attack and Demon.

The pre-arcade, restaurant lobby vector game I have the most vivid memories of is Lunar Lander, 1979. Howard Delman had developed a vector graphics system for Atari, and Lunar Lander was the first game to utilize it. Like Space War, the Lunar Lander game design was public domain. All-text versions of the simulation game had been around for a long time. The first graphic version was written by Jack Burness on a DEC GT40 in 1973. Titled Moonlander, this vector graphics game was controlled with an light pen and is said to have been quite difficult. The lunar surface in the game featured a McDonald's.

Atari's Lunar Lander featured four controllers, rotate right and left, abort, and a distinctive analog thrust controller with a spring resistance mechanism. This controller was incredibly satisfying to operate. It felt like one was operating a serious piece of equipment. Like Stunt Cycle, Lunar Lander was a single player game where the challenge was rooted in learning the physics simulation and in gaining enough skill controlling the vehicle to land it safely. The independent rotate and thrust control mechanism in Space Wars was combined with the gravity-based Newtonian world of Stunt Cycle, but with much more complex gamer input than just acceleration and breaking. The player controlled a landing module which started in free-fall over a mountainous lunar landscape. The idea was to land the LEM on any flat surface without destroying or disabling it. The only enemy to be overcome was one's own lack of experience and skill. The game was about getting somewhere safely. Point bonuses were given for landing on platform areas of various difficultly. The repeating one-screen world of mountains scrolled left or right as the ship approached either side, as did the sparse stars in the background. The text-based origins of the game were reflected in a text readout of speed, altitude and remaining fuel at the top of the screen. It was possible to play through most of the game referencing only the text readout. Instead of a time limit, quarters purchased unit of fuel. For those blessed with an unlimited amount of quarters, the game could played indefinitely without regard to fuel consumption. For the rest of us, it was necessary to develop an economy of fuel use. There was nothing more nerve-wracking than running out of fuel just as one's ship was positioned perfectly for a final decent.

Lunar Lander was the first multiple-perspective video game. As the descending LEM grew closer to any point in the mountain range, the perspective of the camera snapped into a close up position, making all the elements of the game larger and faster for the final landing scene, adding dramatic tension and requiring a slight shift in response time. I remember getting a huge rush from this moment. The magnification effect intensified my focus, which was already concentrated on the limited parameters of the game world, just as the critical moment of the game arrived. The perspective switch also created a feeling of depth to the space of the game. There was more to the spatial dimension of the game world than what could be experienced at first. This sudden, additional power of vision created a feeling that was something like first seeing the scene in Blade Runner where the main character uses a magnifying machine that allowed him to see around corners in a photograph.

Lunar Lander was a popular game, but it was quickly superseded by another vector graphics game that proved to be so popular that it would help establish video games as a form of art and entertainment rivaling television and film: Ed Logg's Asteroids, 1979. When Atari realized how popular the game was going to be, they stopped production on Lunar Lander and started shipping Asteroids in the remaining Lunar Lander cabinets.

I experienced the Asteroids phenomenon in the Space Port arcade in the Quakerbridge mall in Lawrenceville NJ. An entire wall of the arcade was reserved for the game. Adults were playing Asteroids to blow off stream on their lunch breaks. Players had to cue up behind games to get access, and anyone playing had a audience of other players watching from either side, taking notes on rock-destroying technique. The combined thruster rumbles and the pings and crashings of the games would mix in a beautiful, crazed cartoon-like experimental music sound space in the resonating chamber of the arcade.

Asteroids was similar in design and look to Space Wars, but instead of dueling other players, it featured a single player design where the object was to destroy and avoid a swirling field of rocks which broke into smaller rocks you the player shot at them. Part of the game's unique feel came from the contrast of the player's constant active attack with the inert but chaotic momentum of the orbiting asteroids. No game had ever incorporated as many animated objects. It was possible to just watch someone playing Asteroids and marvel at the sight of multiple rocks of different sizes and shapes rotating and tumbling through the closed, continuous world of the game at different speeds. Quarters bought lives, not fuel, and points would lead to extra ships, extending the game play. Skill was rewarded with an extension of game playing time, and good player could play for a long time, fighting the increasing speed and difficultly. Gaining skill, winning more game time and achieving a high score became part of a reward system that made the game especially addictive. Asteroids was also the first game that allowed high score players to distinguish themselves by entering their initials for permanent display.

A color version of the Atari vector graphics system was eventually developed, leading to one of the most original and visually striking games of the time -- Tempest, 1980. Other Vector games less related to the Space Wars model were also produced, including the original first person shooting games, Tailgunner and Battlezone, and the World War I dogfighting game Red Barron, all of which I devoted significant amounts of time to. The game that most fascinated me, though, was Mike Hally's Gravitar.

Graviar, 1982, was a hybrid game that combined, refined, expanded and improved on several games that had come before it. It merged the basic game play elements of Lunar Lander and Asteroids, added a number of new elements and distinguished itself as being one of the most challenging arcade games ever produced. It was not a particularly popular game. The difficultly had the effect of splitting the players into two camps. Those who wanted a quick blast of excitement tended to hate it, since it's initial learning curve was steeper than most new games at the time. Player with more patience and an interest in a greater challenge found it highly rewarding.

The full-color Gravitar, like Lunar Lander, involved descent onto a planet, but instead of one lunar surface, the game featured eleven unique planets divided into three universes. Each planet had a unique landscape and a different level of gravity -- the game had a real level design. The menu screen was itself a game, with gravity from a "Death Planet" dragging at the players ship as they tried to reach each individual world. Once they made it to a planet, a ship would appear in free fall over the planet's surface, but landing wasn't part of the program. Multiple gun emplacements peppered the landscape. Game play involved shooting out the emplacements, evading or shooting enemy ships, and using a tractor beam to get fuel from various locations on the surface. Fuel was a limited resource, it couldn't be bought with quarters. The tractor beam doubled as a shield for protection against enemy fire. The controller set up was similar to Space Wars and Asteroids, and the gravity physics was similar to Lunar Lander, so players familiar with those controls could use skills they had already developed. Using the buttons separately was adequate for the first few planets, but as the difficulty and complexity of the game increased, increasing finger independence on all five controllers was required. Different combinations of thrusting and rotating had to be mixed with toggling between shields and firing, which couldn't be done simultaneously. The independence required to get good at Gravitar approached the level of skill needed for playing a percussive musical instrument.

The close-up perspective-switch of Lunar Lander was upgraded with a real-time zooming animation. This gave the feeling of multiple perspective a more dynamic quality, and, combined with the multiple planets to be explored in the game-universe, made for a feeling of depth and extent in the game unlike another that had come before it. This quality, combined with the patience and leaning curve required to get good at it, and the relative openness of the universe and freedom of approach it allowed make Gravitar more closely related to later console games, like Halo, that combine action with long term resource management and strategy. This may account for it's lack of popularity in arcades, where simple game play and fast games made more commercial sense.

Even more than Asteroids, Gravitar scoring system rewarded skill with points that generated extra ships, increasing the odds of being able to get deeper into the game, and to try explore previously unknown landscapes. This was really the central point of playing -- getting deeper into the game.

Gravitar required unflagging concentration. A momentary drifting of thought or second of worry about something outside the game would quickly lead to disaster. This is an important part of the particular quality of the fully absorbed gamer -- playing well required forgetting about the rest of life, granting a welcome respite from one's normal chains of thought, feelings, and associations. Playing a half-hour of Gravitar would leave one energized and refreshed. This respite was mixed with the pleasure of leaning motor skills through repetitive practice and developing various strategies for solving problems. One could go in any order though any of the planets in a given system, there was no linear path forced onto the player. The game balanced navigation skills with fighting skill, which would often come into conflict because of the design of the ship, which could only shoot up as it's thrusters worked against gravity. Most of the enemy bunkers were below the ship, requiring complex shoot, rotate, and thrust and defend combinations.

The task balancing in Gravitar amounted to patiently learning to artfully manage inertia and limited resources, skills that could be thought of as extended beyond the gaming universe. Along these lines it could be said that the game also encouraged using forces that you couldn't control to your advantage rather than dumbly struggling against them -- it didn't take long to figure out that using the gravitational field of the death star to swing around to the desired planets was far better than wasting fuel blindly struggling against it.

Economy of time is an element of many videogames that helps create their unique feeling of drama. You have gotten this far, don't die now or you'll have to start from the beginning. Gravitar upped the ante on this basic video game dynamic by rewarding skill with a way to save time and skip to the good stuff, using a mechanism which was almost a mini-game in itself. Since there was no way to save, the depth of the game created a problem-- it was tedious to replay all the planets that had already been mastered just to get to a deeper level in the game. To deal with this, Hally placed a Red Planet within each solar system with a spiraling tunnel leading to an exploding nuclear reactor that had to be activated. This would be followed by a timed escape, like the last few minutes of Alien. When the Red Planet was completed, the entire solar system could be skipped. Once I got good at this, I could pick the drama up at it's most interesting point. Starting the game by warping twice in a row with full fuel and many extra ship meant there was a lot to lose very quickly. It also meant that this time I might get deeper into the game than ever before.

The Red Planet concentrated the themes and dynamics of the game--depth, subtlety and variation. There was no gravity, so I had to learn new navigation stills to master it, maneuvering exactly with new physics parameters. This pattern of new challenges created with limited graphic and memory resources was repeated into the deepest levels of Gravitar. Once all three universes had been played, they would repeat, but with their physics reversed and the amount of bunkers increased. This cycle was followed by a stage where the planet's surface was invisible, and finally by invisible landscapes with reversed gravity. Hally got around limited computing power with creative permutations of the rules of the game.

What makes Gravitar engaging even by today's gaming standards is the drama created by the depth of the game design combined with subtly of it's play. The ability to control the navigation of the ship across many different terrains and situations was the central skill needed. Gravitar was about the joys of developing self-control and patience as a way of discovering new challenges.

~ end.


Here are a few emails from Drew about the article:

    From: Drew Gardner
    Subject: Gravitar article
    Date: October 25, 2004 9:13:51 PM MST
    To: Dan Coogan

    Hey Dan-

    Came across your site while working on an article for a book - Gamers-

    My piece features leads up and features Gravitar, happy to send you copy if you're interested.

    Drew Gardner

    From: Drew Gardner
    Subject: Re: Gravitar article
    Date: October 28, 2004 7:25:22 AM MST
    To: Dan Coogan


    The article is based largely on memories of playing Gravitar when it came out in the early 80s. It was one of my favorite arcade games when I was a teenager. By some stroke of luck it was also the one game my college had in the coffee shop, so it held up at a slightly later age as well. The vividness of my memories of Gravitar was sharper than any other arcade game from this era.

    When I was starting the article I looked all around to find an arcade somewhere in or near New York City where I could re-experience it: no dice. So I did the MAME thing, which is great in it's own way.

    You site was very helpful.

    many thanks,

    From: Drew Gardner
    Subject: Gravitar article finally in
    Date: November 17, 2004 9:01:36 AM MST
    To: Dan Coogan


    My editor finally got me the final version of the Gravitar article to give to you - This is a PDF of exactly how it will appear in the book, including screen shots.

    many thanks.

    Drew, You did a great job describing the feeling the player gets while playing Gravitar !
Many thanks to Drew Gardner for the article. He can be reached at: Drew Gardner