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Descent (computer game)

Descent is a 3D first-person shooter computer game noted for popularizing the use of portal rendering technology and providing the player with six full degrees of freedom to move and to look around. Descent spawned two direct sequels (Descent II and Descent III), and Descent: FreeSpace, an interstellar first-person war game. It was developed by Parallax Software and released in 1995.

Table of contents
1 Overview
2 Premise
3 Gameplay
4 Graphics
5 Sequels
6 Source code
7 External links


The original Descent game ran under MSDOS and was (with some tweaking) playable on 486-based PCs at 66 Mhz. With the release of the Intel Pentium, the performance requirements disappeared as an issue. Descent was ported to Apple's Power Macintosh in 1996 and both versions supported multiplayer network play over a variety of protocols. There was a Descent game produced for the Sony PlayStation.

The year Descent was released, 1995, was a year or two after id's Doom but before Quake. Like those programs, it used a software renderer (3D graphics accelerator cards were not yet mainstream on the PC) and shared texturing similarities. Instead of using BSP trees, however, Descent's scene graph employed portals. In this scheme, the player progressed from one enclosed chamber to another, and since the chambers were linked by narrow doors or tunnels, it was a straightforward matter for the program to know that other chambers were unnecessary to render.

Perhaps the more significant improvement over Doom was that Descent used bitmap sprites only for powerups and not for opponents. With true 3D enemies, the game introduced a more frightening level of realism.


The premise of Descent was that the player is the pilot of an armed spacecraft charged with purging mines infested by renegade mining robots. The action always takes place in the mineshafts (as necessitated by the portal renderer). Exiting the mine required the player to locate and detonate the mine's nuclear reactor, causing the exit doors to open. Many of the mines contained hostages, human workers trapped in the mine. It wasn't necessary to rescue any hostages, but a bonus accrued if one did.

The intergalactic mines were owned by the Post-Terran Minerals Corporation. Pilots known as Material Defenders were sent into the mines to undertake the rescue missions and purge the enemy robot infestation. Earlier, the PTMC replaced its human workforce with the robots. The mystery is that no one knows why the mining robots have become hostile. It takes until Descent III to find that out that Samuel Dravis and the PTMC was involved in a huge conspiracy regarding a extremely advanced nanotechnology virus that was able to reprogram the robots in a very quick amount of time, just a few seconds according to what was said in the first FMV of Descent 3 that is played before the first level.


In the original Descent, there are 26 levels corresponding to 26 different and unique mines (and also three secret levels). The first three begin on the Moon, the fourth on Venus, the sixth on Mercury and then back out towards Mars and on towards the moons of the gas giants and finally until Pluto and Charon.

Each levels starts with the player in his ship materializing in a starting location within the mine. The player must then navigate through the mine destroying enemy robots and picking up powerups if his resources run low. Unlike Doom, where the player apparently never fatigued, the player's spacecraft had a fixed energy budget and required regular pickups of energy powerups to be able to continue firing. Killing opponents, however, often released such powerups. There were also permanent recharging areas available.

In Descent and Descent 2, the goal of each level was to find a series of keys, usually in the order of blue, yellow, and red. Each key would correspond with a door of that color. Beyond the red door was the reactor. By shooting at the reactor, it could be detonated, setting off a countdown timer. The player would have to find the route back to the exit tunnel before the countdown expired. An optional objective was also to rescue the trapped PTMC workers in each mine and safely bring them to the exit. In contrast, Descent 3's objectives were more diverse, ranging from escort missions to an ironic mission where you must defend reactors.

Like Doom, Descent provided a navigational wireframe map that would display any area of the mine visited or seen by the player. Since it was truly 3D, however, navigating the map could be challenging.

Although the keyboard interface for moving and rotating in full 3D space was easily learned, many players initially suffered from nausea and confusion since any viewpoint became possible. With practice, however, most people found the game fluid and very enjoyable. A bigger annoyance for casual players was getting lost in the mines (some of which were very large and complex). Highly experienced players who could memorize the mine layouts became adept enough to play the game continually upside-down, but if done for too long, this produced an awful disorientation effect when returning to the real world.

The enemy AI was touted as quite good (and perhaps it was for its day) but in practice was easily defeated. Although the object of simply blowing up robots and a reactor would normally be dull, the overall gameplay was enchanced by the wide variety of weapons the player could wield (and also learn to avoid). There was also the challenge of finding the reactor.

Dying wasn't so bad. Although one found oneself back at the mine's entrance, all the resources (weapons, etc.) acquired thus far would be strewn about the area of death waiting to be reacquired.

The seventh level (which was the end of the shareware version) and the final level are cited as the most difficult. Both have large monster robots that fire powerful weaponry and continually cloak/decloak themselves.

Like Doom, Descent offered excellent competitive multiplayer game play over a LAN. Interestingly enough, Descent is also touted as being one of the first games that allowed on-the-fly joining of multiplayer games, whereas in Doom it is presumed that all players had to be queued prior to initiating the game.

The engine for Descent 1 and Descent 2 operated on the premise of interconnected cubes. Sides of cubes could be attached to other cubes, or display up to two texture maps. Cubes could be deformed so long as their sides remained planar. Walls could also be placed at the common sides of attached cubes to support effects like doors and see-through grating. Unlike in Doom, doors were flat, the level environments were static, and enemies were polygonal instead of sprite-based. However, power-ups and most weapon effects were sprite-based. Of special note was the lighting, which took on many gradients and looked more natural than that of Doom.


The original Descent used indexed 8-bit color in DOS's display mode 13h, using 320 x 200 resolution. The artwork was first-rate, although some textures popped or shifted when viewed from certain angles.


Descent II added more weapon types, more enemy types, different mines, laser-reflecting force field walls, and transporter areas. The most notable additions were the Guide-Bot, a companion robot the player could use to aid in navigation and other tasks, and the Thief-Bot, a fast-moving, hard-to-kill enemy that attempted to steal the player's resources. Graphics were still 8-bit but multiple resolutions were supported. It looked particularly good on the Macintosh.

Descent III switched to use accelerated 3D graphics hardware and improved the rendering engine to support outdoor environments with a nice automatic LOD terrain system. The rain effect in particular was nicely done. The higher resolution and renderer change makes the textures appear flatter, however, and thus the game seems less ominous than its predecessors. Although it was praised and lauded by reviewers, gamers failed to take note, perhaps because of the high system requirements at the time. Descent III was widely considered to be a commercial flop.

A debate exists as to whether or not Volition ever seriously considered doing a Descent 4. It is widely believed that Descent 4 was the working title for what became the popular first-person shooter Red Faction. Observant Descent fans may have noticed that in Descent 1's opening briefing, reference was made to the "Miners First" strike where the miners rebelled against the new robot technology. It is said that this served as a basis for Red Faction, although Red Faction does not directly relate to Descent. An archived copy of the official Descent 4 website started by Volition can be found here: " class="external">

Descent:FreeSpace also used 3D accleration. A main difference was that one could not slide the spacecraft, thus being greatly unable to dodge enemy weapons fire. As the action took place entirely in deep space, it was practically impossible to tell how fast one was moving and in which direction since there were no obvious frames of reference. FreeSpace has no direct connection to the Descent series and was given the "Descent" moniker to avoid trademark issues. FreeSpace had a sequel in the form of FreeSpace 2, but like Descent 3, it was a commercial flop.

On a side note, the Descent series also spawned a trilogy of novels written by Peter Telep and sold at several major booksellers. The titles are Descent, Descent: Stealing Thunder, and Descent: Equinox. The novels did not follow the games to the word, but expanded on the basic premise, and were generally received well.

There were rumors of a Descent movie. A script was commissioned for an NBC TV movie but then was decided to be adapted for movie theaters, Interplay Productions, the owner and publisher of the Descent games, created a division called Interplay Movies that was going to develop popular Interplay franchises at the time the company was created into movies, one of them was Descent, the last known update was way back in 1999 and no new information has since been released so it is considered as dead. Interplay Movies reportedly successfully got Redneck Rampage made into a movie, although it has never surfaced.

Source code

The source code to the original Descent (minus the networking code) was released in 1997. The source code to Descent II and Descent: Freespace has also been released. Open source projects have sprung up around these source releases and can be found on the Internet.

External links