30 Years of Amiga
by Eric Schwartz
from the AmiTech Gazette, June 2015
In Amiga news, the A-EON train barrels along with the acquisition on DVPlayer, a commercial video playing application. This should be valuable if the software is developed further. I know little about DVPlayer myself, so I have no idea what advantages it may have over other video software ported to Amiga/Morph/AROS such as Mplayer or VLC. In Amiga gaming news, Cherry Darling, makers of “Voxel Bird Saga” and other games for Amiga, MorphOS, and mobile platforms, has released “Wings Battlefield,” a head-to-head WW1-style air combat game playable against computer or human opponents (via split-screen or over network). Also the Turrican anthology is coming out, collecting all 3 games from the Amiga Turrican series in one volume for CD-32. You probably weren’t expecting to hear about a new CD-32 release in 2015, even if it is a compilation. I know I sure wasn’t.
With the press on the Amiga’s 30th anniversary, I find myself wishing I could attend one or more of the events going on around the globe, but circumstances unfortunately prevent that. I can’t let it go by completely unheeded, so I have been starting production (more like pre-production) on a new Amiga animation project, unofficially completing a trilogy of musical pieces with “Still Alive” and “Only Amiga” from 2008 and 2010, respectively. With each video I have bumped up the visuals, the first being a black and white animation, and the second a full color rendering. This time I am shooting for HD and 720P resolution, which has forced me to update and rework the 3D models and textures as I strive for a more photo-realistic look (within the limits of old software and my own 3D skill set). I fear I may be a bit too ambitious this time around, and it seems highly unlikely I’ll have this project done in the next month or two while the celebrations are going on. Still, if I can finish it before the year is over, I’m willing to chalk it up as a win. Wish me luck, because I’m probably going to need some.
A few months back, I wrote at length about the reasons and relative merits of the Amiga’s “planar” screen pixels. As I said then, a primary reason for adopting them was that they made more efficient use of smaller amounts of memory. Efficiency was all the rage back then, largely because RAM chips were expensive. Many Amiga veterans remember the days when a couple megabytes of RAM were more expensive than a couple gigabytes today, and that’s not even adjusting for inflation. It’s still fun to look at old computer publications to find some card with a few megabytes of RAM and a 40 meg hard drive retailing for a thousand or more, when now we probably would throw a fit if that 8 gig flash drive costs more than ten bucks. Still, cost of chips drives everything, perhaps more obviously back then. It’s why the Amiga 500 shipped with a measly 512K of RAM, and the A1000 before it had a measlier 256K. Step back to the 1970s, and the Atari 2600 VCS (the spiritual ancestor of the Amiga) had a mere 128 bytes of RAM for runtime data. There was no memory to hold a buffer for the screen. The programs and data on the fixed ROM cartridge generated the screen imagery in time with the television scan rate. This was a very challenging way to work, but it had its own inherent advantages as well. A talented programmer could use the nature of this method of display to make it seem like there are more graphic objects on screen than the Atari was built to display, by changing position, color and other information of an object while the scan progresses, making one object appear to be two different ones. Using display tricks like these and others, hardware originally designed for games like Combat, with two player objects firing missile objects in a simple playfield and little else, the Atari VCS could be made to do surprisingly complex games with many independently moving elements, with only a few K of ROM and less RAM than could hold the average text post on Twitter.
Stepping forward again to the Amiga, there remain a few pieces of that Atari legacy. While the Amiga generally has plenty of RAM to hold a display, it can still do a few scan-line tricks, thanks to the “copper.” At a given scanline, the copper can interrupt the display to change something, like the color value of something. This is seen a lot in games and demos to make a background that changes color without using up a lot of spots in the palette. Better yet, the screen mode or resolution could be changed as well. This was seen in some software, like a part of the interface that required a higher resolution or more colors than the main display. The paint mixer in Deluxe Paint 4, which used the HAM color mode regardless of what mode you were currently painting with, is a good example. A better example is when you have multiple programs each on their own screen, and you drag one down to peek at the one behind it. It works even though the different screens have different color palettes and different resolutions, thanks to the copper and the scan line interrupt, and a little Atari legacy—actually Jay Miner legacy, since he worked on both.
That concludes my ramble for the day. Stay safe, and I’ll see you at the meeting.