CRASH - The Online Edition
— Issue 6 Contents|
How three dimensional is the 3D game? Software houses have been sticking the prefix 3D on computer games for some time now. It’s supposed to help them sell better. But does 3D work, and are all the games labelled as 3D really 3D? CRASH makes an attempt to put things into perspective...
At a small gathering of the computer press held by Hewson Consultants in mid-May, programmer Steve Turner presented a short lecture on 3D in computer games. Steve is known for his trilogy of 3D games produced by Hewsons around the Seiddab theme. Both Steve Turner and Hewsons are concerned about the definition of 3D, and feel that the press should attempt a definition of it. At the gathering Steve put forward his own definition:
‘The player should, for the majority of the playing time, appear to be immersed in a dynamic playing area. There should normally be some approximation to true perspective unless other sufficient strong 3-dimensional cues are present.
‘This definition allows two main types of game to be classified as ‘3D’. In the first type the player is represented by a figure on the screen but his view is from a fixed position above and outside the playing area. 3D effects are generated by strong visual cues in the shapes and shading of the playing area. In the second type the player is not represented on screen but instead has an “eyeball” or “cockpit” view of the playing area. He can manoeuvre within the arena and 3D effects are generated by perspective and parallax using a vanishing point.’
3D arrived in home computer games before the Spectrum. Malcolm Evans (New Generation) had written his Monster Chase (we misleadingly implied his game Escape for the Spectrum was his second when it was actually Monster Chase) for the ZX81 — a classic example. When the Spectrum arrived on the scene there were a few rapid conversions of 3D games to take advantage of the better graphics and colour. The prefix ‘3D’ was immediately recognised as a ‘selling point’ and was often employed quite untruthfully. A not uncommon trick was to add shading to the edges of, say, a maze and call the result 3D even though the game actually played like any other 2D game.
But before games can be defined as 3D or not, it’s important to establish exactly what 3D is.
From the earliest of times mankind has been driven to represent the real world he sees about himself as an image on a flat surface. The caveman painted on cave walls, Leonardo da Vinci had his canvas and George Lucas uses the cinema screen. What is common to all three is that they must convert the three dimensional inspiration to represent it on a two dimensional area and then convince the onlooker that what he is seeing is real.
Humans have two eyes, set slightly apart. Each eye provides the brain with an image, but these images are offset from each other by a tiny amount. You can achieve triangulation (a method of judging the distance to an object) as long as there are two triangulation points. The eyes form two such points, and as a result of the offset images, the brain is able to calculate distance and therefore depth. It is this sense of depth which we perceive in the world around us that has driven artists to recreate it in paintings.
During the renaissance period (starting about AD 1290) artists began to examine the concept of perspective and within another century had worked out the mathematics required to reduce the seen world to a flat canvas in such a way that an onlooker could believe he was really seeing a suggestion of depth in the picture. None of these devices has changed over the intervening years, and today’s computer programmers must still use them if they wish to create a three dimensional image.
Perspective is the most important, but there are other visual cues which tell the brain that an object has depth. The classic form of perspective is usually referred to as Vanishing Point Perspective. Put simply, this says all parallel lines converge at a point on the horizon (see figure 1). From this simple concept, all other forms of visual cue emerge.
It doesn’t take much imagination to take this concept a stage further and state that an object nearer to the observer will be larger than a similar one which is further away; nor that an object which is not moving actually straight at the observer will appear to take a diagonal path across the observer’s field of view. From these three basic ideas, most computer games derive their three dimensionality.
There is a second form of perspective, usually referred to as Projection or Isometric Perspective. It is used a lot in technical drawings (see figure 2). The objects depicted are seen from above and to one side. Instead of allowing lines of similar length to diminish in height as they move away from the observer (in accordance with Vanishing Point Perspective) they are made to remain identical. Games like 3D Ant Attack or the classic arcade Zaxxon are examples of this sort of perspective. Isometric perspective can be quite realistic as long as other visual cues are provided. An important addition is that of light and shade. The brain accepts that sunlight comes from one side and affects a solid object. Look at figure 3. What you see is a hexagon (six-sided shape) with three lines radiating from the centre. With little effort it can be seen as a three dimensional cube. But in figure 4 some shading has been added, and now there’s no doubt that you are seeing a three dimensional cube.
Another visual cue which helps isometric perspective to work is what we might call Hidden Views. Figure 5 depicts two circles, one broken by running into the other. Because the unbroken one is bigger, we have no difficulty in accepting that the two circles are identical in size but that one is smaller because it is farther away from us, and we know therefore that it is really disappearing slightly behind the nearer one. Technically this is absurd — but it works anyway because the brain is used to interpreting visual information from the seen world in this way. In summing up isometric perspective, we can say it is less visually effective than vanishing point perspective, but can still work perfectly well if additional visual cues are provided for the brain.
So we have a sense of depth created by perspectives which incorporate distance and size related to distance. Objects nearer to us are bigger and they eclipse objects farther away that appear smaller. Light and shade create an illusion of solidity, and when these elements are all combined convincing 3D results. But there are three other important elements to consider. Due to the thick atmosphere we live in, light is refracted in such a way that distant objects appear fainter or paler. As a result the brain tends to accept that a paler or dimmer object is farther away than a brighter or more strongly defined one. The arcade game Battlezone uses this principle, and Steve Turner uses it in 3D Lunattack where distant fighters have less lit pixels in their graphics than those ‘nearer’ to the player. The second element is parallax movement. When you sit in a car or train, the landscape closest to you flashes by far faster than the landscape in the distance. If you look at figure 6 you can instantly see that the lengths of lines A and B are different, A being much longer, although in reality they would be the same because the vanishing perspective lines are supposed to be parallel. It follows that objects must move faster the nearer they are to cover the same distance. The third element is focus, something which is a modern concept of distance, one brought home by the advent of the camera. The eye, of course, can focus across an enormous range of distance — the camera cannot. Today we are so used to seeing photographed images incorporating a depth of field which has near and distance objects out of focus, that we have come to accept this as another visual cue. It is this device which we have played on to produce this month’s cover of CRASH. The painting was done in several layers and cut out before being photographed, as you can see in figure 7.
The problem confronting the computer programmer is what sort of perspective to choose, and when having done that, how to implement it in the program. Vanishing Point Perspective is an obvious choice because it is the one the eye accepts instantly. But there are serious problems.
For a start off, this will require objects to zoom out of the screen at the player, which means that each object must be defined many times over, i.e. as small and distant, big and close, and as many stages as possible in between. Obviously the more animation stages employed, the more realistically 3D the graphic will appear. Classic examples of this are Zzoom (Imagine) and, better still, Deathchase (Micromega). Even 48K of RAM becomes insufficient if a lot of characters must be stored for each object as it grows bigger, and especially so if there are to be a lot of different objects to be moved. Compromises must be decided upon to get as much information in to handle the graphics while leaving enough space for the game commands and handling.
With Isometric Perspective the programmer’s life is much easier because the scenery only has to be defined once as it doesn’t change shape physically during the game. Look at Ant Attack (Quicksilva) and you’ll see this exactly. The city is a large graphic over which the screen scrolls, so the only problem is the scrolling, the blocks of the city don’t have to be redefined with every movement. Obviously this takes up much less program space than Vanishing Point Perspective graphics. The disadvantage, however, is that the game can only be played from one height as it is only from a strictly fixed vantage point that the isometric perspective will work. With Vanishing Point Perspective the player can alter height convincingly, and even move from side to side (like Pole Position type games).
When all this has been sorted out, and the programmer has decided how many of the other sophisticating elements he can add to the game to increase the 3D effect, you can begin to see that Steve Turner’s definition of a 3D game is pretty spot on.
There have been a large number of games produced for the Spectrum which claim to be 3D. In part two of this article, we examine many of them closer in the light of Steve Turner’s definition and see how successful they are at presenting a three dimensional image.
AMAZING, STAGGERING, UNBELIEVABLE, — all words that have been used to describe home computer game graphics. But how often have you thrilled to the blurb and then wished you could have drilled the programmer with his own photon laser blaster when you got the game home and discovered how staggering it was — staggeringly bad?
As we have seen in part one, there are really two different types of perspective in use, and these tend to define the type of game or, rather, the vantage point from which the game is played. Vanishing point perspective tends to the game where ‘you’ are ‘in’ the screen, i.e. the ‘cockpit’ type game. Isometric perspective tends to the game where ‘you’ are represented on the screen by a character, which for convenience we will refer to as a bird’s eye view. There are, of course, some anomalous games which come somewhere in between or play with space in a three-dimensional way, but aren’t visually 3D on the screen — as we shall see.
Programmers and sometimes software houses tend to concentrate on a particular type of game. Malcolm Evans and his New Generation Software have been one such. Escape was an early and striking example of 3D, striking because of the lovely colouring and 3D because of the way the maze is constructed. Malcolm has ranged across both forms of perspective. Escape is decidedly bird’s eye view, a fixed vantage point from which your man must be guided through a series of complex mazes made of hedges. The amazing monsters which chase you through the maze are a definite hazard, but the player is confronted by the difficulty of finding the horizontal pathways which are hidden behind the height of the hedges. Visual cues are provided by shading the colour and also by the character animation — characters face in the direction of their travel. They do not change size, however, as this is isometric perspective.
With the follow-up 3D Tunnel, Malcolm turned to a cockpit view as you guide yourself along a twisting tunnel filled with flying objects to be shot as they come towards you. Visually 3D Tunnel is less satisfactory. The effect is generated by alternating squares of colour set one inside another. These jerkily ‘move outward’ by growing bigger until they grow out of the screen. Going round a corner is done by offsetting the small start squares so that their edges touch the outer ones. The result works, but only just. Interestingly 3D Vortex (JK Greye) tried the same thing but used spiraling pixels to better effect. It resulted in a smoother image but was spoiled by the objects, which were very jerky.
In the end both games suffer from a lack of overall definition as far as 3D goes, leaving the brain working too hard to conjure up a sense of reality.
Knot in 3D fared better, New Generation’s third game and second ‘cockpit view’ type. Knot also scored because the concept required a readjustment of thinking from the player, which made it more than just a 3D game. In effect Knot in 3D is a three dimensional ‘Light Cycles’ game where the player must fill up the available space before the computer does. You control a ‘light trail’ and, as in the two-dimensional variety, you must avoid hitting your own trail or that of the computer, the winner being the one to make the other crash.
Malcolm’s next offering was Corridors of Genon, another cockpit view game based on the classic 3D maze principle. Here, the corridors are all curved, the visual cues being wall shaped (receding with distance) and colour shading. The graphics are quite simple, although implemented well in the protagonist, Bogul, who grows bigger in stages as he approaches.
The recent Trashman sees a return to the bird’s eye view of isometric perspective, employing hidden views (Trashman disappears behind objects between him and you) and light and shade techniques to create an effect of solidity in the buildings and hedges. Colouring too is used to great effect.
These examples of 3D games from New Generation illustrate very well the difference between the two perspective views and also the problems the programmer faces in using them. Of these games the most sophisticated graphically are Escape and Trashman — the bird’s eye views — where the defined graphics are fixed and unaltering during play. Without exception the cockpit games are simpler, creating 3D with shape and vanishing point perspective, but unable to do it perfectly because of the limitations of memory and the complexity of the calculations required to move objects realistically through space towards the player.
If the cockpit view places problems in the programmers’ paths, they have nevertheless been elegantly overcome in a number of games. A 3D maze necessarily requires walls drawn in perspective in order to work. But once the shape has been worked out, it can be repeated endlessly without eating up much more program. A number of maze games have contented themselves with very simple views in which each step leaps into view so that the perspective may work, but the effect of moving between walls does not.
Omitting the ubiquitous ‘3D’ from the titles, we have Monster Chase (Romik), Maze of Gold (Gilsoft), Maze (Impact) among the earlier Spectrum offerings, and the more recent Quetzalcoatl (Virgin), The Skull (Games Machine) and Bat Attack (Cheetah Soft). Monster Chase, Quetzalcoatl and The Skull all have monsters in them — not unlike Bogul in Corridors of Genon — but The Skull uses its monsters best of all, with the skulking skulls sliding into corridors from behind walls when you least expect them.
All these 3D maze games suffer from the above-mentioned lack of smooth movement although Quetz and The Skull do have a larger number of steps to create a reasonable sensation of forward movement. The one game which outshines them all in this respect is Zig-Zag (DK Tronics) which has employed a very clever device to create the 3D illusion. Here, vertical black stripes make up the walls, with accurately shaped floors and ceilings cutting into them. This very simple graphic device recreates perspective extremely well, allows continuous forward movement AND allows the player to ‘turn his head’ when going round corners. Its supreme advantage is in the economy of memory used to create the effects. The monsters being chased in the game also obey the laws of perspective by growing smaller as they run away and being progressively hidden by intervening objects like projecting walls.
If you are suffering with a problem in describing a three dimensional space enclosed by walls, why not turn to an easier medium — space? In space there are no walls to hear the programmer scream, and a sense of depth can be created by having objects merely change size as they approach or move away. The result of this understanding has been a number of excellent and not so excellent games of space shoot ‘em up. Among the earliest offerings John Hollis’s Timegate (Quicksilva) has become a classic, if a little confusing when it comes to the scoring! 3D here is a relatively simple visual matter. There are no peripheral objects to be moved in perspective as there would be on the ground, only the alien ships have to be coped with. 3D Spawn of Evil (DK Tronics) was a very similar game which suffered from space ship uncontrollability; although it isn’t directly related to three dimensionality, heavy objects are affected by inertia, they can’t just go from zero speed to flat out without accelerating or slowing down — both above-mentioned games incorporated this effect into the space craft, sometimes making lining up a shot near to impossible. It can be a nice and realistic touch though.
Other games which quickly followed suit were Galaxy Attack (Sunshine Books), Space Wars, Seiddab Attack and Lunattack (all by Hewson) and Space Station Zebra (Beyond). The 3D Seiddab trilogy (Hewson) written by Steve Turner makes another example of a programmer working his ideas out gradually through a series of games. Unlike Malcolm Evans of New Generation, Steve Turner has concentrated on the cockpit view exclusively, each game getting better and more complex until the recent 3D Lunattack, where a sense of flying through a three dimensional space is about as perfect as a small home computer can allow and leave room for a playable game. This concentration on vanishing point perspective is about to change with Steve’s new game, a 3D adventure which employs a unique mixture of vanishing point and fixed vantage (almost) isometric perspective.
The outstanding 3D space game is probably Derek Brewster’s Code Name Mat (Micromega) which employs a highly complex form of dynamic 3D. In this respect, the use of the word ‘dynamic’ implies that life carries on even if the player can’t see it — in other words, just because an alien space ship has zoomed off the edge of the screen, it doesn’t mean the computer has forgotten it — it may be lining up a shot on you or circling back. This is true of Code Name Mat and 3D Lunattack. The effect of craft flying towards and past you in CNM is marvellous, but additionally 3D is used in another way when navigating with the ‘distant view’ facility which requires an adjustment of the thinking process (not unlike Knot in 3D) in order to see it working.
One final point before leaving space 3D cockpit games — as objects approach they get bigger BUT they should also get more detailed. Again, it’s a problem of constantly redefining the graphic as it moves, and some of the games mentioned here do it better than others.
Staying in space, but getting out of the cockpit, we get the combination of space shoot ’em up with vanishing point graphics but where the player seems to hover outside the picture. This has been a relatively recent development and the games that instantly spring to mind are Blade Alley (PSS), Orpheus (CRL) and Deathstar (Rabbit). Blade Alley uses some of the maze game techniques with reasonable success as far as a three dimensional quality goes. Alternating colours flash outward along fixed baffles of increasing size and height to create the perspectivised trench-like effect of these games. Deathstar is very similar but relies more heavily on the strong perspective lines of its trench. Oddly, Rabbit’s game has chosen to break the perspective parallax rule. It has a series of dotted lines moving from the vanishing point outwards toward the player along the walls and floor of the trench. Perspective demands that these should start slowly and increase in speed as they approach the player but the reverse happens — in Deathstar poor programming or poor thinking. It spoils the effect of the perspective. Orpheus relies on a single drawn line radiating outward from its vanishing point to create the effect of flying down a long cavern. It’s a primitive and ineffectual device which isn’t helped by the jerky advance of the alien objects to be shot. In Blade Alley this aspect works very well with several stages of animation being employed to create depth and movement.
Graphically, one of the best games of this type is Ad Astra (Gargoyle Games). The animation of the alien craft is pretty standard to the type with fewer animation stages to create forward movement than in Blade Alley, but the real miracle happens with the rolling asteroids. These display all the classic rules, change of size and apparent speed, correct perspective movement, increase of observable detail as they approach (the craters on the surface are even animated to rotate as the planetoid rolls on its axis), hidden view as one obscures another object, and finally shading which is very well done. And in common with Blade Alley and Deathstar, the perspective drawing of your ship is distorted as it moves from side to side or alters height on the screen. All of this calls for a lot of program to redefine the graphics. Ad Astra does it very fast and smoothly.
As Spectrum programming has become more sophisticated so has vector movement improved. This is a method by which the position of a point in space may be determined relative to another and constantly monitored so as to give a consistent perspective result. It applies very much to 3D games of course. Programmers tend to have their own particular methods for vector movement.
The method is nowhere more acutely needed than in wire frame 3D or ‘hollow’ 3D. Games using this device are generally based on the arcade classic Battlezone. CRL had an early game which approximated the type — 3D Desert Patrol, but it was eclipsed by the appearance of 3D Combat Zone (Artic). Here we have a much more mathematically accurate representation of vanishing point perspective, one which allows that the vanishing point is not a sole dot on the horizon, but actually all the visible horizon. This means that the objects can be defined continuously to provide a highly realistic outline of their shape which is always altering depending on how it moves, or how the player ‘moves’ in relationship to the object. What it lacks is a solid feel, since the objects are all made up of lines. The eye can often be confused as to what is the front and what is the back of the object. But the advantage to the programmer is that he only has to define the shape of the objects initially, and after that the vector part of the program will take care of the movement and the compression caused by perspective. In lacking solidity, the games lack light and shade and hidden view — in being effectively transparent, several shapes can intermingle with each other. Nevertheless a very large and dynamic playing arena can be created with a genuine sense of movement and three dimensionality.
Artic went on to use the same system in their Dimension Destructors, except that this was set in space and so lacked the feeling of a landscape — to its detriment. Months later the tank battle was fought again in Rommel’s Revenge (Crystal). Crystal provided a background mountainscape which Combat Zone lacked, adding to the sense of space, but emphasising the one essential compromise in this type of game — the fact that you can never reach the limits of the playing area; as you approach the mountains, so they seem to recede before you — a symbol for life perhaps?
A very young company called Real time have now produced a version called Tank Duel, which employs the same hollow 3D graphics but in much greater profusion than either Combat Zone or Rommel’s Revenge and has added solid colouring to the plain and to the background landscape, increasing the sense of depth and space. It works very well indeed.
Vector movement is important to almost any 3D game of course, for plotting positions of objects relative to each other. But there are many games which have avoided its complications, and many which are successful because they employ the range of visual cues for the eye to fasten on.
Shortly before Christmas Quicksilva astonished us with Sandy White’s remarkable Soft Solid 3D Ant Attack. This Scottish programmer had managed to combine 3D effects which took account of architectural solid objects as well as soft human shapes. Ant Attack is the classic example of bird’s eye view perspective for the Spectrum as Zaxxon is for the dedicated arcade machine.
Ant Attack uses a fixed isometric perspective over a large area which is then merely scrolled as the player moves his character about the area. To help the sense of solidity, the ‘buildings’ are all accurately shaded and additionally the ‘live’ characters disappear behind them when required. The usual disadvantage of a bird’s eye view, that it is fixed, has been alleviated in this game by allowing four fixed positions at each compass point. However, the game also illustrates the main problem of the perspective, that you can’t get down into it, since this would mean redefining the main graphics, and an increase in height would show up the problem that exists with the false or non-existent horizon — it would ‘sink’ with the foreground and look silly.
In looking at Zaxxan (Starzone), the Spectrum version of the famous arcade game, one is reminded of those television shots which use a telephoto lens. The foreshortening effect of the long lens makes distant objects actually as big or even bigger than the nearer ones. Zaxxan’s 3D lets your space ship to move sideways (in effect, diagonally away from you) for a considerable distance without appearing to hit the wall which is directly behind it. Even though it isn’t visually apparent, a distinct space has been artificially created. The main visual cue here is the shadow on the ground, a common theme with Blade Alley and Deathstar. But because of the isometric perspective, the further reaches of the trench are the same size as the nearer. In the main, this does not disturb the player much, and the additions of shading and hidden view add to the 3D effectiveness.
Recent additions to the bird’s eye perspective are Android 2 (Vortex), Pedro (Imagine) and Haunted Hedges (Micromega). Of these three Android 2 and Haunted Hedges are a variation on the theme of Malcolm Evans’ Escape, mazes where horizontal pathways are hidden behind the height of the hedges or maze walls. Haunted Hedges was Derek Brewster’s first incursion into isometric perspective and the result (a 3D Pacman type game) is less satisfactory than the complexities of his later Code Name Mat. Here, the 3D is really only a visual gimmick which has little to add to the playing of what is a fairly straightforward ghost gobbler. Android 2 is another matter, a complex game of various stages in which the 3D graphics add greatly to the visual excitement and playing difficulty. Mines hidden behind walls can be fatal!
Pedro is slightly different in that the perspective is not used to hide things — another case of 3D for its own sake, as it adds little to playing the game and indeed makes controlling the man awkward and frustrating.
Imagine fared much better with perspective in their best-selling game Zzoom. If Zaxxon is a 3D Scramble type game, then so is Zzoom, and a number of other similar programs. The difference between Zaxxon and Zzoom is that the former is a bird’s eye view, whereas the latter is a cockpit view. The effect of travelling low over a road towards the ever-receding horizon works quite well with correct visual cues contained in the perspective lines and the increasing size of approaching enemy craft. The effect is entirely spoiled by the outsize refugees marching along on the horizon and whereas the player can accept the horizon never getting any nearer (it doesn’t in real life after all) it is harder to accept that you never get any nearer the refugees. This is a good example of a programming compromise which is almost unavoidable in the circumstances. It doesn’t however actually spoil playing the game.
The other games which have something in common with Zzoom are the road racer games based on the famous Pole Position arcade favourite, and flight simulation games. An interesting early Spectrum attempt at a 3D road racer game is Turbo Driver (Boss UK). Here the 3D effect barely exists — it’s almost a Cubist perspective. The cars are seen from well above although they are drawn with a slight foreshortening, and the road is described by two lines set wider at the base of the screen and narrower at the top. This pays lip service to a sense of depth but the game makes no real attempt to be 3D.
After a long gap a rash of road racers appeared. First was Grand Prix Driver (Britannia), closely followed by Road Racer (Thorn EMI) and Speed Duel (DK Tronics). The most convincing was Chequered Flag (Psion). Britannia opted for a very low view point and hollow 3D graphics with a moving background landscape. The 3D is effective, only the playability of the game suffers from elements which have little to do with the 3D. Road Racer and Speed Duel are played from a higher position, almost a bird’s eye view in fact. The road racer games have this in common, that they use the vanishing point perspective very effectively, creating a fine sense of speeding along a winding road, and yet they are played not as a cockpit view. The exceptions are Chequered Flag (which places you more in the driver’s seat) and the excellent 3D Deathchase (Micromega). Chequered Flag’s driver height playing position makes the sense of objects sweeping past you much more effective than is the case with Speed Duel or Road Racer. But for sheer thrills Deathchase has to be the winner. Here, perspective almost is the game. The movement of the tree trunks from horizon to collision or near miss is exceptional. The game is full of neat touches like the exploding bikes, the disintegrating chunks of which you sail through as you dash on. Since your bike is very manoeuverable, the programming required to cause the trees to weave about in accurate perspective is complicated and beautifully implemented.
Flight simulation games may appear to have more in common with 3D space games, but for the fact that the 3D view has to relate to fixed points on the ground. The first was Psion’s Flight Simulation. Nightflite (Hewson) followed soon after and was later improved as Nightflite 2. These games require a very accurate and mathematical use of vanishing point perspective in order to convince — back to the vector movement programming. A runway must be constructed to work as a proper perspective from any angle of approach and at any height. The least touch of isometric perspective and the illusion is ruined. Naturally, with so much vectoring to be done as well as program command handling, it isn’t surprising that flight simulations tend to be somewhat undetailed when it comes to the ground. Flight Simulation gets round the problem by only providing features like lakes and the runways. Nightflite’s elegant solution is contained in the title — pinpricks of lights on the ground describe the view and create a quite effective sense of flying over villages and towns at night.
The most exciting and busy simulation was Fighter Pilot (Digital Integration). This game provides a similarly undetailed landscape as that in Flight Simulation, but adds extremes of speed and the chance to attack enemy fighters in aerial combat. The fighters are seen in full 3D and react quite properly in the three dimensional space in which they are placed. This effect was even better used in their follow-up Night Gunner, where the aerial dog fights manage to look like old World War II newsreel shots.
Still on the flying theme, Heathrow ATC (Hewson) and Airliner (Protek) can also claim to be 3D, but in a different way to the other games. Here the player must think three dimensionally although the screen display is not 3D. Airliner does have a 3D view of the runway on approach however. The computer is playing around in 3D conceptually and the player must also think similarly — it’s a sort of thinking man’s 3D. Arguably the games are not visually 3D in the accepted sense though.
There are a few other games which use 3D in odd ways. Atic Atac (Ultimate) is interesting. The rooms are described in a form of bird’s eye perspective which allows all four walls to be in view, the vanishing point being straight through the floor. But this is not isometric perspective despite the bird’s eye view. Apart from this cue, the rest of the game is quite two dimensional with the objects and characters seen flat on — Picasso would probably have approved of the mixture of perspectives!
Moonbuggy (Anirog) could hardly be described as 3D, yet it employs the visual cue of parallax movement, with the foreground moving much faster than the background mountains. If this device had been used with several ‘layers’ of landscape it would have given a convincing illusion of depth.
Psytron (Beyond) uses 3D in an oddly classical way — the colour is quite flat but over it is drawn a landscape in strong perspective. Enemy craft are animated in 3D, growing bigger as they approach, but hidden views are not employed. Shading is incorporated into the drawings of the base, and the overall result is curiously like that of a good-quality comic.
Luna Crabs (Micromega) is an earlier attempt at 3D by author of 3D Deathchase, Mervyn Estcourt. The 3D in this game is used from two other games which rely for the effect of trajectory to create depth are the early 3D Tanx (DK Tronics) and Terror Daktils (Melbourne House). The shells fired in 3D Tanx diminish in size as they fly towards the distant tanks on the bridge and the result works very well. The game’s skill lies in estimating the angle of fire to reach the four lanes of tanks on the bridge. The tanks, however, appear unaffected by perspective — a convenience which saves having four different graphics to describe tanks in the foreground, mid and background lanes. This is perspective in bits and pieces!
Terror Daktils employs the same effect with trajectory and diminishing size of shell as it flies towards the massed beasts. But this game additionally boasts rather excellent line drawn monsters which fly out at you, getting bigger as they approach and swoop down. Both these games use 3D as an important aspect of playing but still represent a less sophisticated level of 3D development than we have seen recently.
Finally, there is 3 Deep Space (Postern) — the first ‘real’ 3D game. But is it real? It works on the stereoscopic system whereby two images are provided on screen, slightly separated (like a double exposure) and in opposing colours. The player wears spectacles with one green lens and one red. Each eye then sees one of the separated images and the brain interprets the two differing images as one and so thinks there is depth to the scene. It can work very effectively. Here, we are back to the theory of vanishing point perspective — parallel lines converging at a point on the horizon. The closer together the separated images are, the farther away the object seems to be from the viewer.
That’s the theory — in practice 3 Deep Space doesn’t work, probably due to the Spectrum’s limited colour attribution which makes it hard to get just the right amount of separation between the images. The result is that the player is forced to ‘work’ very hard to get even an unsatisfactory effect of 3D. So stereoscopic 3D would appear to be a cul-de-sac for the moment — more of a gimmick than a device.
But with games like Ant Attack, Code Name Mat, Deathchase and Fighter Pilot, we can safely say that the prefix 3D to a game is no longer the gimmick it used to be, and further, that the use of 3D in all these games is an integral part of their excitement and challenge. 3D games have come a long way from the paltry addition of a bit of shadow to the edges of a maze. But in the words of Steve Turner — we haven’t seen anything yet! He is now looking towards a generation of games where the animated and 3D graphics will be as good as those seen on the loading screens we have become so used to.
Report compiled by the CRASH team — useful arcade info by Lloyd Mangram and snotty-nosed technical stuff by Roger Kean, and thanks to Steve Turner.