On Friday 9 November 1984 the first copies of Ultimate’s Knight Lore reached the CRASH offices in Ludlow. A rare Ultimate press release had promised “an entirely new three-dimensional concept with superb animation called Filmation”, and “anxious readers ran riot with their letters”. What they got was a castle drawn in solid-looking forced perspective, in which Sabreman could walk behind a pillar and disappear from view, climb onto a block and jump across a gap, all without the flicker that usually came with moving graphics on a ZX Spectrum. CRASH gave it 94%, with 97% for graphics, and one reviewer called it “probably the best game yet produced for the Spectrum”.
Filmation was a name, not a product. It covered the way Ultimate Play the Game, the trading name of the Stamper brothers’ Ashby Computers and Graphics, drew and moved things in Knight Lore and Alien 8. A second version, Filmation II, made the view scroll for Nightshade and Gunfright. The trick was copied so widely that by 1988 CRASH could look back on “unimaginative clones which sometimes threatened to swamp all the review pages with their identical, and by then extremely boring, isometric screens”.
Fast facts
- Made by: Tim and Chris Stamper’s Ashby Computers and Graphics, trading as Ultimate Play the Game.
- First game: Knight Lore (ZX Spectrum, November 1984).
- Filmation II: the scrolling version, first used in Nightshade (1985).
- Other machines: Knight Lore was converted to the Amstrad CPC, BBC Micro and MSX; Nightshade reached the BBC Micro and the Commodore 64.
- Source code: never published by Ultimate; a full annotated disassembly of the Spectrum Knight Lore is public.
What was new
Isometric views were not new on the Spectrum. CRASH’s own history of the form starts with Quicksilva’s Ant Attack (1983), “the first game with truly three-dimensional views”, followed by Vortex’s Android 2 and Hewson’s The Legend of Avalon in 1984. What Knight Lore added was a room full of solid objects that could overlap and be moved about. CRASH’s reviewers put it down to “the new technique of masking, so that the moving characters do not flicker at all when they pass in front of other objects”, and to a choice about colour: “only one colour is used per screen which avoids any attribute problems”, with a different colour for each room.
The same reviewers noticed that being able to hide things was a weapon as well as a spectacle. “Ultimate have used the hidden view idea very cruelly, so that a hint may be given of something nasty crouching behind a stairway — but you’re never sure until it’s too late.” Their box of special features listed simply: “filmation which allows you to do almost anything with the objects in the game”.
How Knight Lore draws a room
Ultimate never explained Filmation, but the Spectrum game has since been taken apart. The annotated disassembly by the programmer known as tcdev, published in 2017, shows how each piece works.
Every object lives in 3D. A room holds up to forty objects: Sabreman, the special objects he collects, and the blocks, arches and hazards of the scenery. Each has an x, y and z position and a width, depth and height, which together make a box in the world. Collisions, jumps and falls are worked out with those boxes, not with pictures.
Projection is two additions and a halving. The screen position comes from the world position by adding x and y for the distance across, and subtracting them, halving the result and adding the height for the distance down. There is no multiplication and no perspective, which is why the view slopes two pixels across for every pixel down. The isometric projection entry explains why games on a pixel grid chose that slope.
Order comes from comparing pairs. To decide what to draw first, the game compares objects two at a time, checking whether their boxes overlap along each of the three axes, and uses the combination to decide which of the pair must go behind. This handles long and short objects side by side, which a single sorting number such as the screen height cannot. Y-depth sorting is the simpler method it avoids.
Drawing is masked, into a buffer. Each sprite is stored as pairs of bytes, picture and mask. The mask clears the pixels the object covers and the picture is then combined in, so the scenery behind shows through the gaps without being overwritten. Everything is drawn into a 6,144-byte copy of the Spectrum’s bitmap and then copied to the display, so the player never sees a half-drawn frame. When something moves, the game wipes only the area flagged as changed and redraws the objects there, rather than the whole room.
Tables replace work. At start-up the game builds lookup tables of bytes shifted by one to seven pixels, for drawing at any horizontal position, and of bytes with their bits reversed, so one picture can face either way. Rooms are described as short lists of scenery pieces and positions: the table describing all of the castle’s rooms takes under 2.5K, where a single stored Spectrum screen needs 6.75K.
That last point is the one magazines abroad singled out when they explained the technique to their own readers in 1987. In Brazil, Micro Sistemas pointed out that a hi-res screen took about 6K, so a 48K machine could hold “only eight screens” if each were stored as a picture; its answer was “modularidade”, building every room from reusable parts. In Spain, Amstrad Semanal printed a routine that added two new commands to the Amstrad CPC’s BASIC so readers could move masked graphics “con el método Filmation” in their own programs.
Ultimate’s Filmation games
| Game | CRASH | What the review saw |
|---|---|---|
| Knight Lore (1984) | Issue 12, 94% | The debut: one colour per room, masking, “probably the best game yet produced for the Spectrum” |
| Alien 8 (1985) | Issue 15, 95% | A robot reviving a starship’s “cryogenically frozen beings” before it arrives; 129 screens. “It looks just like Knight Lore a lot of people exclaimed, feeling obscurely ripped off” |
| Nightshade (1985) | Issue 21, 91% | Filmation II: “the scenery scrolls rather than ‘flicks’”, and a building’s front wall disappears as you walk in |
| Gunfright (1986) | Issue 25, 92% | A western. After a first stage of shooting bags of money, “Filmation II (Ultimate’s 3D masking routines) rears its head again” |
| Pentagram (1986) | Issue 29, 93% | Sabreman again, “one of the follow ups to Knight Lore”, though “the action tended to slow up when there was a lot on the screen” |
| Bubbler (1987) | Issue 41, 78% | “Breaks no new ground… the 3D perspective isn’t as convincing as that used in previous Ultimate products” |
Filmation II was the one real development. CRASH’s Will Brooker described it in 1988 as “an Ultimate invention” that “allows graphics of Knight Lore’s quality to be scrolled smoothly over a large playing area”. Nightshade traded something for it: there were, the CRASH reviewer noted, “no objects which you can shunt about and use whilst playing”. On the Commodore 64 the cost was speed. ZZAP!64 found the conversion “intolerably sluggish” and gave it 54%; the tape carried a colour version and a slightly faster black-and-white one.
By Bubbler in 1987 CRASH was writing Ultimate’s epitaph: “Once Ultimate was on a pedestal above all other software companies… Sadly those glorious times are long since gone.” The Stampers had by then moved on to Rare and Nintendo’s consoles.
Followers
Other programmers took the idea further within a year. The Edge’s Fairlight, by Bo Jangeborg, scored 95% in CRASH in November 1985, and one reviewer wrote that it “knocks Filmation and Filmation 2 into a cocked hat. And there’s a game behind the graphics too”. Another put the complaint plainly: “Ultimate first introduced us to realistic 3D graphics but sadly not a lot of game was bolted on to them.” Jon Ritman and Bernie Drummond made Batman (93%) and then Head Over Heels (97%) for Ocean, and by then CRASH was noting that “there have been quite a few games of this style lately — and pretty as they are, many have been severely lacking in gameplay”. By 1988 CRL’s 3D Game Maker, in Brooker’s words, enabled “everyone to rewrite Knight Lore”.
The idea also reached consoles. Software Creations in Manchester built Solstice for the NES, published in America by CSG Imagesoft in 1990. Its designer, Mark Wilson, told Edge in 2007 that the programmer Mike Webb “came into work one day with a method for doing a Knightlore-style isometric game on the NES”, and that “Solstice would not have existed if not for the examples set by Knight Lore”. A Super NES sequel, Equinox, was announced by Sony Imagesoft in 1993. Much later, the magazine Fusion greeted Lumo (2016), a modern isometric puzzle game, as “a clear nod to the 3D isometric games of the 80s such as Head over Heels and Knight Lore”.
Sources
- CRASH, issue 12 (Christmas Special, January 1985): p. 8, the first copies of Knight Lore arriving on 9 November 1984; pp. 16-17, review (masking, one colour per room, the hidden view, “special features: filmation”, 94%).
- CRASH, issue 15 (April 1985), pp. 16-17: Alien 8 review (the frozen crew, 129 screens, 95%).
- CRASH, issue 21 (October 1985), pp. 10-11: Nightshade review (scrolling scenery, no movable objects, 91%). Computer Gamer, issue 7 (October 1985), p. 67: Nightshade “updated to Filmation II”.
- ZZAP!64, issue 11 (March 1986), p. 24: Nightshade on the Commodore 64 (two versions, the speed, 54%). Acorn User, issue 46 (May 1986): Nightshade for the BBC Micro at £9.95. Conversions of Knight Lore: as listed in the Knight Lore entry (Acorn User issue 40, Amstrad Action issue 1).
- CRASH, issue 22 (November 1985), pp. 26-27: Fairlight review.
- CRASH, issue 25 (February 1986), pp. 60-61: Gunfright review.
- CRASH, issue 28 (May 1986), pp. 120-121: Batman review. Issue 29 (June 1986), pp. 134-135: Pentagram review. Issue 39 (April 1987), pp. 20-21: Head Over Heels review. Issue 41 (June 1987), pp. 19-20: Bubbler review.
- CRASH, issue 51 (April 1988): pp. 35-38, Roger Kean on Ultimate (the Filmation press release and readers’ letters, “revolutionary”); p. 83, Will Brooker, “Run It Again!” (Ant Attack, Android 2, Avalon, Filmation 2, the clones of 1986, 3D Game Maker).
- Amstrad Semanal, Amstrad Especial 5 (July 1987), p. 55: Alberto Suñer, “Técnica Filmation”.
- Micro Sistemas, issue 72 (September 1987), pp. 10-12: Renato Degiovani, “Os segredos da Filmation II”.
- Knight Lore (ZX Spectrum) annotated disassembly by tcdev (2017), SkoolKit conversion by Michael R. Cook (2019), in the repository mrcook/zx-spectrum-games on GitHub: the object table, projection, pairwise ordering, masked drawing, screen buffer, run-time tables and room data. https://github.com/mrcook/zx-spectrum-games
- Nintendo Power, issue 14 (July 1990), p. 44: Solstice from CSG Imagesoft. Issue 44 (January 1993), p. 27: Equinox.
- Edge, issue 181 (November 2007), pp. 104-105: “The Making Of Solstice”.
- Fusion, issue 1 (2018), p. 14: Lumo review. Lumo’s 2016 release: Wikipedia, “Lumo (video game)” (web, secondary).