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Alpha Waves
Developer(s)	Infogrames
Publisher(s)	Infogrames (International)/Data East (North America)
Designer(s)	Christophe de Dinechin
Release date(s)	1990
Genre(s)	Platform game
Mode(s)	Single player (DOS), two simultaneous players (Atari ST)
Rating(s)	N/A
Platform(s)	Amiga, Atari ST, DOS
System requirements	10Mhz processor, CGA, EGA, VGA, or Monochrome graphics (DOS version)
Input	Keyboard, Joystick

Alpha Waves (also known as Continuum) is an early 3D game that combines labyrinthine exploration with platform gameplay. By most definitions of the genre it could be considered to be the first 3D platform game, released in 1990, 6 years before the genre's seminal classic Mario 64. It was an abstract game with a moody, artistic presentation, curiously named for its supposed ability to stimulate the different emotional centers of the brain with its use of color and music.

It was developed initially for the Atari ST by Christophe de Dinechin, and later ported to the Amiga and DOS. The DOS port was done by Frédérick Raynal, a notable game designer who would go on to develop Alone in the Dark, and Little Big Adventure. He has said that his work on Alpha Waves was a major inspiration for AitD. The PC version was also localized in North America by Data East, and retitled Continuum. Infogrames may have also published their own version in the US under the original title, and it was also released as a part of no less than two Infogrames compilations, on which it retained its original name.

Contents 1 Gameplay 2 Version differences 3 Technology 4 External links

Alpha Waves is a simple game. It features two main modes of play: Action and Emotion. The core gameplay in both is the same.

Players guide one of six craft (which are little more than geometric shapes in many cases) onto trampoline-like platforms. On these platforms, the player bounces automatically, higher, with each jump, until he reaches the maximum height possible for that platform (some are stronger than others). Every room in the game is a cube, and the walls contain doorways leading to other rooms. In this way, players have to work their way through the game's rooms, and reach different areas based on different emotions.

In Action Mode, players also work against the clock. Time bonuses are awarded for entering new rooms, and keys can be collected to open new ways. There isn't a particular end to the game, but the goal is simply to last as long and to discover as much as possible before time runs out. Emotion Mode allows players to explore the levels freely, without the time constraints.

Alpha Waves was initially released on the Atari ST. This version is notable for allowing two players to compete simultaneously. It lacked music entirely on the Atari 520ST, because of insufficient memory to store the music samples. On Atari 1040ST and later models, the theme song played during the intro. The music was stored on the second side of the floppy disk, since any Atari ST with enough memory also had a dual-sided floppy drive. A promotional version of the program was distributed by a french magazine on single-sided floppy disks, crashing any machine with more than 512K of memory.

The Amiga port was second. This version added a theme song at the title screen, but nixed the multiplayer aspect. The interface is similar, but the zone select in Emotion has been redone. Beyond this, it is very similar to the original.

The DOS version was the last one, and contains a number of improvements. This version supported AdLib/SoundBlaster sound cards. Despite the fact that these used the more limited FM synthesis of the Yamaha YM3812, compared to the PCM synthesis of the Amiga, Alpha Waves is one of the rare exceptions where the AdLib sound quality is superior. The soundrack was also expanded to play in-game, and each zone had its own music. Additionally some of the mobiles have been changed, level layouts tweaked, and the camera tilting toned down for easier viewing. The menus and level selection screen have been redone again, and are noticeably enhanced.

The DOS version still lacks the two player mode of the ST, and it also lacks a mechanism to regulate speed when played on systems faster than it was intended for (essentially causing it to play in fast forward on newer hardware). However when played on a properly configured system or emulator, this can be considered the superior version for solo play.

Alpha-Waves may have been the first video game featuring full-screen, flat-shaded 3D graphics on a microcomputer. Games of the same era like Falcon or Starglider typically displayed 3D graphics on a very reduced portion of the screen. On the Atari ST, Alpha-Waves also featured a simultaneous two-players mode, the screen being split in half vertically.

Alpha-Waves ran on 16-bit microcomputers that did not have hardware floating-point capabilities. For that reason, it performed all perspective and rotation computations using only integer arithmetics. In order to avoid using integer multiplications, which were expensive at the time, it described objects using displacements that were multiples of a base vector. For instance, a square in the Z plane would have been described as "+1X +1Y -1X -1Y". As a result, the vast majority of geometric computations were performed using only additions, not multiplications.

The computation of sine and cosines was similarly done using only integer arithmetic. All angles were represented using not degrees, but 1/256th of a circle. A lookup table contained the value of the sine multiplied by 32767. Multiplying this value by a 16-bit coordinate gave a 32-bit value, and the 16-bit high-half of that result was used.

Another key to performance was a highly optimized polygon-filling routine, which used a number of tricks, including an assembly version of Duff's device to achieve a very high fill rate, besting the in-house self-modifying routine Infogrames was using at the time.

The Atari ST and Amiga versions were written in assembly language. The DOS version was written in C.

• Review and download at the Home of the Underdogs
• Continuum at MobyGames
• Atari ST original source code