Digitised Sprites
Real actors, pixel form
Digitised sprites are video frames of real actors reduced to a machine's palette. In use on the C64 by 1988, made famous by Pit-Fighter and Mortal Kombat; not to be confused with Rare's rendered sprites.
Digitised sprites are photographs or video frames of real people and objects, captured, cut out and reduced to a machine’s palette, then used as game graphics in place of drawn ones. The look was in use on 8-bit home computers by 1988, reached arcade fighting games with Atari’s Pit-Fighter in 1990, and became a house style at Williams/Midway with Mortal Kombat and NBA Jam. It faded when rendered 3D models and then real-time polygons offered the same realism with smoother motion.
Fast facts
- Earliest uses held here: MicroLeague Wrestling and The Three Stooges on the C64 (reviewed 1988); Dynamix’s David Wolf: Secret Agent on PC (reviewed 1990).
- Arcade: Pit-Fighter (Atari Games, 1990), “the first beat ‘em up to use digitised characters” (Megatech, 1991); Williams’ own claim of NARC (1988) as its first digitised game.
- Defining use: Mortal Kombat (Midway, 1992) and its sequels; NBA Jam (1993).
- Not the same thing: pre-rendered CG sprites (Donkey Kong Country, Killer Instinct) are 3D models rendered offline, not photographs.
Digitised versus rendered
Two techniques of the same years get confused because both produce sprites that look “more realistic than hand-drawn”.
| Type | Source | Examples |
|---|---|---|
| Digitised | Real actors or objects on video or film, frames captured and palette-reduced | Mortal Kombat, Pit-Fighter, NBA Jam, MicroLeague Wrestling |
| Pre-rendered | 3D models rendered on workstations, output as sprites | Donkey Kong Country, Killer Instinct |
Edge described Rare’s pipeline in 1994: “Everything in the game — the sprites, the backgrounds and the 6,000+ frames of animation — is rendered”, using “Alias’ PowerAnimator software running on Silicon Graphics equipment”. No camera was involved. Hand-drawn sprites (Street Fighter II) are the third category, and the one Edge preferred: “Mortal Kombat II’s digitised fighters lack the personality of their more cartoon-like counterparts in Street Fighter II.”
How Mortal Kombat did it
Nintendo Power visited Williams during Mortal Kombat 3 and got the process from Ed Boon and John Tobias.
Casting. “Some of the actors are martial artists and some of them aren’t,” Tobias said. “Basically they just have to be real … They have to be able to withstand eight hours of jumping, ducking, kicking, hitting and flying across the screen.”
Shooting. Moves were acted out first by Boon and Tobias for the performers — “We show them how to fly across the screen,” Boon joked — and “many moves are unplanned and come from improvization during the shooting sessions”.
Digitising and clean-up. “Once the raw video was shot and digitized, the frames got individual attention. Character frames were limited to 64 colors, but John Tobias and Steve Beran bumped certain colors to enhance clarity and spent endless hours retouching everything by hand.” The backgrounds were not photographs at all: one artist “uses 3-D rendering programs to create some of the elements”, another “puts together the finished scene using programs like Photoshop”.
Budget. MK3 took “10 months and seven people” and “18 Megabytes of ROM … more than twice as much memory as the original Mortal Kombat”. Frame count is where the memory goes, which is why the technique was always tighter on home machines than in the arcade.
Economies
Palette swaps. One actor in one costume, recoloured, is several characters. A 1994 review of the Amiga conversion complained that arcade fans “will quickly notice such shortcuts as using the same frames of animation for Scorpion and Sub-Zero” with only a colour change.
Fewer frames. Video runs at 25 or 30 frames a second; a cartridge cannot hold that for every move of every character, so frames are dropped. On the Amiga the result was that Mortal Kombat’s visuals “may look good in still pictures — but when seen in action, the jerkiness and poor animation is immediately apparent.”
Scaling hardware. Pit-Fighter’s coin-op paired its “256-colour digitised graphics” with “specialist hardware to shrink and scale the sprites and backgrounds so that the viewer’s ‘camera’ can follow the fighting action”. The home conversions had no such hardware; Teque’s Peter Jefferies stored the sprites as 64×64 16-colour images and called the scaling “without doubt the hardest aspect”.
Before the arcades
The technique did not begin with Pit-Fighter. MicroLeague Wrestling on the C64 “features Hulk Hogan and other stars of the Stateside ring”, with “digitised interview sequences between ‘Mean Gene’ Okerlund and each wrestler” — Zzap!64 found the graphics “well-timed but sometimes indistinct”. Cinemaware’s The Three Stooges had “superb digitised graphics” the same month. Dynamix’s David Wolf: Secret Agent on PC used “actors and digitised graphics”, which a reviewer in early 1990 said “set it apart from every other game of its kind” and gave it “a very adult atmosphere”. Williams’ Roger Sharpe told Nintendo Power that NARC (1988) was “the first game, to use digitized graphics”; it was at least the first at Williams, and NBA Jam five years later was “using digitized graphics extensively”, to the point that “some of the actual players who are featured in the game have made comments like ‘It would be great if I really could shoot three-pointers like that!’”
Reception and decline
The realism was the point and the problem. It made Mortal Kombat’s violence look like violence, in the years when Senators Lieberman and Kohl were sponsoring “video game rating legislation” and Sega was printing its own ratings on boxes. And it dated quickly: by late 1994 Edge could assume readers had “railed against poorly digitised actors laid on top of unimaginative rendered backgrounds”. Rendered sprites, then real-time polygons, gave the same photographic ambition with animation that did not stutter, and motion capture took over the job of getting real performers into a game.