Hitting the Books: Amiga and the delivery of 256-color gaming | Engadget

With fashionable consoles providing avid gamers graphics so photorealistic that they blur the road between CGI and actuality, it is easy neglect simply how cartoonishly blocky they had been within the 8-bit period. In his new guide, Creating Q*Bert and Other Classic Arcade Games, legendary recreation designer and programmer Warren Davis remembers his halcyon days imagining and designing a number of the greatest hits to ever grace an arcade. In the excerpt beneath, Davis explains how the business made its technological leap from 8- to 12-bit graphics.       

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Back at my common day job, I turned notably fascinated with a brand new product that got here out for the Amiga pc: a video digitizer made by an organization known as A-Squared. Let’s unpack all that slowly.

The Amiga was a just lately launched dwelling pc able to unprecedented graphics and sound: 4,096 colours! Eight-bit stereo sound! There had been picture manipulation applications for it that would do issues no different pc, together with the IBM PC, might do. We had one at Williams not solely due to its capabilities, but in addition as a result of our personal Jack Haeger, an immensely proficient artist who’d labored on Sinistar at Williams just a few years earlier, was additionally the artwork director for the Amiga design workforce.

Video digitization is the method of grabbing a video picture from some video supply, like a digicam or a videotape, and changing it into pixel knowledge that a pc system (or online game) might use. A full-color {photograph} would possibly comprise hundreds of thousands of colours, many simply subtly totally different from each other. Even although the Amiga might solely show 4,096 colours, that was sufficient to see a picture on its monitor that seemed virtually completely photographic.

Our online game system nonetheless might solely show 16 colours complete. At that stage, photographic pictures had been simply not attainable. But we (and by that I imply everybody working within the online game business) knew that might change. As reminiscence turned cheaper and processors quicker, we knew that 256-color programs would quickly be attainable. In truth, after I began wanting into digitized video, our {hardware} designer, Mark Loffredo, was already taking part in round with concepts for a brand new 256-color {hardware} system.

Let’s discuss shade decision for a second. Come on, you already know you wish to. No worries when you don’t, although, you possibly can skip these subsequent few paragraphs when you like. Color decision is the variety of colours a pc system is able to displaying. And it’s all tied in to reminiscence. For instance, our online game system might show 16 colours. But artists weren’t locked into 16 particular colours. The {hardware} used a “palette.” Artists might select from a reasonably wide selection of colours, however solely 16 of them may very well be saved within the palette at any given time. Those colours may very well be programmed to alter whereas a recreation was working. In truth, altering colours in a palette dynamically allowed for a typical method utilized in outdated video video games known as “color cycling.”

For the {hardware} to know what shade to show at every pixel location, every pixel on the display screen needed to be recognized as a type of 16 colours within the palette. The assortment of reminiscence that contained the colour values for each pixel on the display screen was known as “screen memory.” Numerically, it takes 4 bits (half a byte) to characterize 16 numbers (belief me on the maths right here), so if 4 bits = 1 pixel, then 1 byte of reminiscence might maintain 2 pixels. By distinction, when you wished to have the ability to show 256 colours, it could take 8 bits to characterize 256 numbers. That’s 1 byte (or 8 bits) per pixel.

So you’d want twice as a lot display screen reminiscence to show 256 colours as you’d to show 16. Memory wasn’t low-cost, although, and recreation producers wished to maintain prices down as a lot as attainable. So reminiscence costs needed to drop earlier than administration accredited doubling the display screen reminiscence.

Today we take with no consideration shade resolutions of 24 bits per pixel (which doubtlessly permits as much as 16,777,216 colours and true photographic high quality). But again then, 256 colours appeared like such a luxurious. Even although it didn’t method the 4,096 colours of the Amiga, I used to be satisfied that such a system might lead to near photo-realistic pictures. And the concept of getting movie-quality pictures in a online game was very thrilling to me, so I pitched to administration some great benefits of getting a head begin on this know-how. They agreed and acquired the digitizer for me to mess around with.

The Amiga’s digitizer was crude. Very crude. It got here with a bit of {hardware} that plugged into the Amiga on one finish, and to the video output of a black-and-white surveillance digicam (offered individually) on the opposite. The digicam wanted to be mounted on a tripod so it didn’t transfer. You pointed it at one thing (that additionally couldn’t transfer), and put a shade wheel between the digicam and the topic. The shade wheel was a round piece of plastic divided into quarters with totally different tints: crimson, inexperienced, blue, and clear.

When you began the digitizing course of, a motor turned the colour wheel very slowly, and in about thirty to forty seconds you had a full-color digitized picture of your topic. “Full-color” on the Amiga meant 4 bits of crimson, inexperienced, and blue—or 12-bit shade, leading to a complete of 4,096 colours attainable.

It’s exhausting to consider simply how thrilling this was! At that point, it was like one thing from science fiction. And the coolness of it wasn’t a lot the way it labored (as a result of it was fairly rattling clunky) however the potential that was there. The Amiga digitizer wasn’t sensible—the digicam and topic wanted to be nonetheless for therefore lengthy, and the time it took to seize every picture made the method mind-numbingly gradual—however simply being able to supply 12-bit pictures in any respect enabled me to begin exploring algorithms for shade discount.

Color discount is the method of taking a picture with quite a lot of colours (say, as much as the 16,777,216 attainable colours in a 24-bit picture) and discovering a smaller variety of colours (say, 256) to greatest characterize that picture. If you possibly can do this, then these 256 colours would type a palette, and each pixel within the picture could be represented by a quantity—an “index” that pointed to one of many colours in that palette. As I discussed earlier, with a palette of 256 colours, every index might match right into a single byte.

But I wanted an algorithm to determine how one can decide one of the best 256 colours out of the hundreds that is likely to be current in a digitized picture. Since there was no web again then, I went to libraries and started combing by means of tutorial journals and technical magazines, looking for analysis carried out on this space. Eventually, I discovered some! There had been quite a few papers written on the topic, every outlining a distinct method, some simpler to know than others. Over the subsequent few weeks, I carried out just a few of those algorithms for producing 256 shade palettes utilizing take a look at pictures from the Amiga digitizer. Some gave higher outcomes than others. Images that had been inherently monochromatic seemed one of the best, since lots of the 256 colours may very well be allotted to totally different shades of a single shade.

During this time, Loffredo was busy creating his 256-color {hardware}. His plan was to help a number of circuit boards, which may very well be inserted into slots as wanted, very similar to a PC. A single board would offer you one floor aircraft to attract on. A second board gave you two planes, foreground and background, and so forth. With sufficient planes, and by having every aircraft scroll horizontally at a barely totally different price, you possibly can give the phantasm of depth in a side-scrolling recreation.

All was transferring alongside easily till the day phrase got here down that Eugene Jarvis had accomplished his MBA and was returning to Williams to go up the video division. This was huge information! I believe most individuals had been fairly enthusiastic about this. I do know I used to be, as a result of regardless of our motion towards 256-color {hardware}, the video division was nonetheless with no robust chief on the helm. Eugene, given his already legendary standing at Williams, was the proper particular person to take the lead, partly as a result of he had some robust concepts of the place to take the division, and in addition because of administration’s religion in him. Whereas anyone else must persuade administration to associate with an thought, Eugene just about had carte blanche of their eyes. Once he was again, he instructed administration what we would have liked to do and so they made certain he, and we, had the assets to do it.

This meant, nonetheless, that Loffredo’s planar {hardware} system was toast. Eugene had his personal concepts, and everybody shortly jumped on board. He wished to create a 256-color system primarily based on a brand new CPU chip from Texas Instruments, the 34010 GSP (Graphics System Processor). The 34010 was revolutionary in that it included graphics-related options inside its core. Normally, CPUs would don’t have any direct connection to the graphics portion of the {hardware}, although there is likely to be some co-processor to deal with graphics chores (resembling Williams’ proprietary VLSI blitter). But the 34010 had that functionality on board, obviating the necessity for a graphics co-processor.

Looking on the 34010’s specs, nonetheless, revealed that the velocity of its graphics features, whereas well-suited for gentle graphics work resembling spreadsheets and phrase processors, was actually not quick sufficient for pushing pixels the way in which we would have liked. So Mark Loffredo went again to the drafting board to design a VLSI blitter chip for the brand new system.

Around this time, a brand new piece of {hardware} arrived within the market that signaled the subsequent era of video digitizing. It was known as the Image Capture Board (ICB), and it was developed by a bunch inside AT&T known as the EPICenter (which finally cut up from AT&T and have become Truevision). The ICB was considered one of three boards provided, the others being the VDA (Video Display Adapter, with no digitizing functionality) and the Targa (which got here in three totally different configurations: 8-bit, 16-bit, and 24-bit). The ICB got here with a bit of software program known as TIPS that allowed you to digitize pictures and do some minor modifying on them. All of those boards had been designed to plug in to an inside slot on a PC working MS-DOS, the unique text-based working system for the IBM PC. (You could also be questioning . . . the place was Windows? Windows 1.0 was launched in 1985, however it was terribly clunky and never broadly used or accepted. Windows actually didn’t obtain any type of recognition till model 3.0, which arrived in 1990, just a few years after the discharge of Truvision’s boards.)

Slightly little bit of trivia: the TGA file format that’s nonetheless round immediately (although not as common because it as soon as was) was created by Truevision for the TARGA collection of boards. The ICB was an enormous leap ahead from the Amiga digitizer in that you possibly can use a shade video digicam (no extra black-and-white digicam or shade wheel), and the time to seize a body was drastically lowered—not fairly instantaneous, as I recall, however solely a second or two, fairly than thirty or forty seconds. And it internally saved colours as 16-bits, fairly than 12 just like the Amiga. This meant 5 bits every of crimson, inexperienced, and blue—the identical that our recreation {hardware} used—leading to a true-color picture of as much as 32,768 colours, fairly than 4,096. Palette discount would nonetheless be a vital step within the course of. The best factor in regards to the Truevision boards was they got here with a Software Development Kit (SDK), which meant I might write my very own software program to manage the board, tailoring it to my particular wants. This was really superb! Once once more, I used to be so excited in regards to the prospects that my head was spinning.

I believe it’s protected to say that most individuals making video video games in these days thought in regards to the future. We realized that the velocity and reminiscence limitations we had been pressured to work below had been a brief constraint. We realized that whether or not the online game business was a fad or not, we had been on the forefront of a brand new type of storytelling. Maybe this was a bit extra true for me due to my curiosity in filmmaking, or perhaps not. But my experiences up to now within the recreation business fueled my creativeness about what would possibly come. And for me, the holy grail was interactive motion pictures. The notion of telling a narrative through which the participant was not a passive viewer however an energetic participant was extraordinarily compelling. People had been already experimenting with it below the constraints of present know-how. Zork and the remainder of Infocom’s textual content journey video games had been in all probability the earliest examples, and extra would comply with with each enchancment in know-how. But what I didn’t know was if the know-how wanted to realize my finish aim—totally interactive motion pictures with film-quality graphics—would ever be attainable in my lifetime. I didn’t dwell on these visions of the longer term. They had been simply ideas in my head. Yet, whereas it’s good to dream, in some unspecified time in the future you’ve acquired to return again all the way down to earth. If you don’t take the one step in entrance of you, you might be certain you’ll by no means attain your final vacation spot, wherever that could be.

I dove into the duty and started studying the particular capabilities of the board, in addition to its limitations. With the primary iteration of my software program, which I dubbed WTARG (“W” for Williams, “TARG” for TARGA), you possibly can seize a single picture from both a reside digicam or a videotape. I added just a few totally different palette discount algorithms so you possibly can strive every and discover one of the best palette for that picture. More importantly, I added the flexibility to search out one of the best palette for a bunch of pictures, since all the pictures of an animation wanted to have a constant look. There was no chroma key performance in these early boards, so artists must erase the background manually. I added some instruments to assist them do this.

This was a far cry from what I in the end hoped for, which was a system the place we might level a digicam at reside actors and immediately have an animation of their motion working on our recreation {hardware}. But it was a begin.