The Atari ST and Amiga computing evolution! The Amiga and Atari ST computers (of course along with Macintosh and Apple IIGS) had enough processing power to perform calculation-intensive graphics (and other type of processing) activities at acceptable speeds. Surely back in the mid 80's the great processing speed of the Motorola 68000 chip (65816 on the Apple IIGS), the high memory capacity, and of course the ability for the programmers to call native system routines, opened up entirely new categories of programs, game graphics, audio performance and more. But in short, what were their graphical and sonically differences between the mighty Amiga and the strong Atari ST? The article is concerned with the early Amiga OCS-chipset systems (Amiga 1000/500/2000) and the Atari 520/1040 ST/STF/STFM series.
The Amiga graphics (OCS) The Amiga graphics chip offered user-definable modes and a staggering palette of 4096 colors. Normal operational modes include 320 by 200 (NTSC) or 256 (PAL) pixels resolution with 32 colors on screen at once or 64 colors screen with a special mode called EHB (Extra-HalfBrite) in which are used 32 arbitrary colors plus 32 half-bright components, 640 by 200 (NTSC) or 256 (PAL) with 16 colors, and another special mode called Hold-And-Modify (HAM) mode which lets you have all 4096 displayed at the same time in low resolution, but restrictions come in to play which make this mode less than useful for animation (HAM animation = displaying series of HAM images due to RAM limitation). Using a special technique called interlacing the Amiga can double its horizontal line count (at the cost of intrusive flickering on most monitors). With specialized chips like the Copper co-processor and BliTTer chip the Amiga makes light work of shifting large amounts of screen memory and display different horizontal resolutions, different color depths, and entirely different frame buffers on the same screen. Amongst its facilities are eight 3-color and four 15-color hardware sprites.
The Atari ST graphics The ST offered far fewer screen options than the Amiga. Only three ST screen modes are available (low, medium, high), whilst the Amiga offers nine different modes in non-interlaced modes, and a total of 20 different modes counting interlaced, extra-halfbrite, and hold-and-modify. So, the Atari ST has three modes or resolutions and a palette of 512 colors or an increased color palette of 4,096 colors only for the (late) STE/TT models. Only two of the modes permit color though. This is controlled by the video-chip, called Shifter. Low resolution offers 320 by 200 pixels with a maximum of 16 colors on screen at once or with a rapid palette switching ability the maximum number of colors to be displayed on-screen at once to 512 (static screens only). Medium resolution manages 640 by 200 pixels with 4 colors on screen. High resolution offers a whopping 640 by 400 pixels but in black and white only (which also requires a special monitor, say the SM125). Neither horizontal scrolling nor sprites are available through hardware, although vertical scrolling is! Only the Mega, STE (and a few late 1040 STFM) models came with BliTTer chip, which speeds animation, but not many games were developed to use the advantage of Blitter.
So, what was their graphics evolution? In games, obviously rapid palette switching was more effective at any time on the Amiga than on the ST/STE for just a simple reason: the Amiga could show by default 32 colors on screen at once and the Atari only 16. Then if you the Amiga to change the entire palette a few times during the game to give the impression of more colors on screen, you get (at least) twice the amount of colors on screen in the Amiga version. The special chip named Copper, allows the Amiga to display different horizontal resolutions, different color depths, and entirely different frame buffers on the same screen. The usage of the BliTTer in the Amiga systems, in which the "Blit" is shorthand for "block image transfer" or bit blit, is a highly parallel memory transfer and logic operation unit. It has three modes of operation: copying blocks of memory, filling blocks (e.g. polygon filling) and line drawing. The BliTTer allows the rapid copying of video memory, meaning that the CPU can be freed for other tasks. Surely without these custom chips, the inability to support hardware sprites, the less effective rapid palette switching, the Atari ST struggled to perform smooth sprite animation, smooth background scrolling, and eye-catching colored screens. But still, although the Amiga superiority in graphics, the ST computers offered quality graphics, far superior to the other home-computers back in the days. But what made the Amiga series revolutionary in graphics was then usage of third party software and hardware offering real-time TV quality animated scenes! There are a lot to remember and mention a few such as the DigiView by Newtek (a simple video capture device that it would take snapshots of a single frame of video and save it to a floppy disc in the Amiga's 4096-color HAM mode), the mighty Video Toaster (an aspiring video editor, including the squishing and flipping effect and a dazzling array of custom wipes and fades), VideoScape 3D by Aegis Software (a 1998 rendering and animation program), and of course the amazing LightWave3D (a 1990 3D modeling, rendering, and animation package) which was used in the whole first season of Babylon 5 sci-fi TV series to do the job by modeling and then rendering CG spaceships on the Amiga!
The Amiga sound (OCS) The custom sound chip called Paula, provided the Amiga with stunning synthesizer-like musical power. Four voices can be used which have fully definable wave forms. Amplitude or frequency modulated sound are possible too. It has four DMA-driven 8-bit PCM sample sound channels. Two sound channels are mixed into the left audio output, and the other two are mixed into the right output, producing stereo audio output, and with the ability to increase the number of possible voices (simultaneous sounds) through software mixing! Of course using this highly custom sound chip, CPU utilization was minimal. Thus every game and demo run fluid with minimal glitches in (say) graphics. Most of the games and demos offered impressive sound quality, fully stereo and with a variety of sampled sound effects, along with stunning synthesizer-like music. Of course, the Amiga could offer MIDI instruments connection support via external devices. For most, the Amiga sound was the best innovative out-of-the box capability of the Amiga evolutionary hardware!
The Atari ST sound Sadly he ST's sound chip, the Yamaha YM2149, leaves a lot to be desired. It's only capable of producing square sound waves through three channels - similar to the chips found in the Amstrad CPC and Spectrum +2 computers! Most of the games offered chip-sounds (SFX and music), and just a few supported quality music or sampled SFX but mostly sacrificing smooth scrolling and/or sprite animation as for the inexistence of custom sound chip and keeping the CPU restless! Fortunately due to the 16 bit Motorola CPU and the high RAM capacity the ST series could offered good quality sampled introductory (mostly) game themes. However, the inclusion of MIDI ports means there's a wealth of instruments that can be controlled from the ST, thus the ST series were quite famous for their out-of-the box MIDI capabilities, with plenty of third-party MIDI software and a lot of professional musicians as primary users! The famous Cubase audio editing software by Steinberg for example, was initially released in April 1989 for the Atari ST offering 16 tracks MIDI sequencer!
So, what was their sound evolution? In games and demos, obviously the Amiga sound hardware was way more effective than on the ST/STE for just a simple reason: the Amiga sound chip could support more voices which can be used and with fully definable wave forms, producing fully stereo output. This specialized sound chip, keeps CPU utilization minimal, and thus games or demos run fluid without major glitches when over-loaded with graphics and special graphics techniques such as parallax-scrolling etc. The Amiga sound was the best innovative out-of-the box capability of its revolutionary hardware! On the other hand, the ST without such powerful sound chip, struggled to perform high quality sound especially in games and demos. But still, although the Amiga superiority in sound quality, the ST computer series offered professional sound , far superior to the other home-computers back in the days and, especially when MIDI instruments synthesis required thanks to its CPU, RAM expansion and its famous built-in MIDI ports. If you was a professional musician back then, you would certainly go with an Atari ST or Mega ST using powerful audio editing and MIDI sequencing and scoring software such as Steinberg's Cubase (which by the way were initially released for the Atari ST!) or C-Lab's Atari Notator. And with the use of special third party Genlock devices, the ST/STE series could easily offer good quality video/music editing studios, limited of course to the ST's hardware.
Sound samples International Karate + (aka IK+) was a karate fighting game produced by System 3, back in the 1987. What is really impressive here, are the sounds FX which were produced using high-quality digitized samples from karate/fighting movies and Bruce Lee-style cries. More on that, the Amiga version features a great main menu music in 4-channels stereo, composed by Dave Lowe and performed several years later at the Symphonic Game Music Concert III in 2005 as well! The game was voted Best 16-bit Soundtrack of the Year at the Golden Joystick Awards!
Graphics samples A few graphics comparisons below (in static, otherwise when gameplay occur the differences are mostly huge!)
The Juggler demo! Eric Graham's legendary Amiga demo The Juggler shows a robot juggling three mirror balls in a 24 frames demo. The Amiga demo was one of the earliest full-color 3D ray-traced animations rendered and displayed on a personal computer. When released in 1986 no other personal computer could have run anything like it. The frames were encoded in the Amiga's HAM (Hold-And-Modify) display mode which uses a highly unusual technique to express the color of pixels. This allowed to display up to 4096 colors on screen which is much more than otherwise would be possible.
The Atari ST version (produced later on 1987 by Tri-Vision, Martin Doudoroff) was a 512k version demo which has 4 frames less than the original Amiga demo and limited to 16 colors but with little noticeable loss!
Atari ST version
The famous Gorilla drawing!
One of the most famous demo drawings offered out-of-the-box in Deluxe Paint art software, was the Gorilla painting by Greg Johnson (video games designer). The (original) Amiga version is using 32 colors while the ST version offers 16 with remarkable results!
Atari ST version
Defender Of The Crown (Cinemaware 1986)
Defender of the Crown is a strategy computer game designed by Kellyn Beck. It was Cinemaware's first game, and was originally released for the Commodore Amiga in 1986, setting a new standard for graphic quality in home computer games.
Atari ST version
King Tutankhamun (Deluxe Paint)
King Tutankhamun drawing by Avril Harrison was so amazing at the time (1986) that became the box-art of the Deluxe Paint series painting software!
Atari ST version
Amiga (Clipper by Rick Parks / Deluxe Paint image 320x400 EHB mode)
Atari ST (Tower 320x200 / Deluxe Paint ST)
Venus The Flytrap
Venus The Flytrap is an excellent 2D multiplatform shoot-em-up release by Gremlin Graphics in 1990 for the Commodore Amiga and Atari ST. The scrolling and sprite animation is seriously smooth and the number of colors is quite impressive in both Amiga and Atari ST versions.