Watching PasIntro (Atari 8-bit)

If you write a new high-level compiler for an 8-bit system, what do you do in order to promote it? Well in the case of Mad Pascal for the Atari 8-bit, the developer was Tebe of Mad Team so the most obvious way for him to showcase what his shiny new utility is actually capable of was always going to be to create a demo with it. The result is PasIntro and, considering it’s not running at flat out assembled code speeds, the results are surprisingly impressive.

There are two routines included, a large twister and some Kefrens bars. The latter is somewhat anaemic – I’m assuming it’s actually rendering everything to a back buffer over multiple frames rather than racing the raster and drawing a new bar on each scanline as it’s about to be displayed like these routines would normally do – but it still works reasonably well despite that. Where PasIntro shines visually however is the large, colourful twister routine which looks very smooth and has an independently-moving grid effect behind it which is a very neat touch.

But the biggest selling point for me personally is the bit that wasn’t written in Pascal, the soundtrack from Wieczor of Lamers which starts playing as the demo’s pre-calculation begins and continues behind both of the effects as they cycle through their presets. It really does have to be up there amongst my all-time favourite pieces of POKEY music and adds to the experience as a whole.

Watching Onedimensional (Atari 8-bit)

Running over last weekend was the latest edition of the Atari-centric Silly Venture party which has spent nearly two decades bringing fans of all things Atari together to party, chat and do demo-ish things; there were some great releases over the various Atari platforms as always, but I found myself drawn to one particularly old school demo which took part in the 16K Atari 8-bit competition. It’s called Onedimensional, was coded by Shadow of Noice and is basically a 1980s-style raster intro which features a four colour logo parked at the top of the screen, a double font scrolling message trundling past at the bottom and industrial quantities of raster bars dancing like nobody is watching between them.

This really couldn’t be described as pushing the Atari 8-bit’s boundaries and Shadow himself commented that it’s a “compo filler” in the scroller, but regular readers will know I love me some raster bars so a new production that does lots of variations on that particular theme is always going to catch my eye. The graphics are reasonable and do what they’re there for – Rocky’s logo is well drawn but part of me wants a teensy bit more colour – whilst the music was composed by Tobikomi (who appears to be a newcomer to the POKEY by the look of it) and is quirky but fun, suiting the on-screen action well especially since all of the effect and logo colour changes have been synchronised to it.

To be honest, I resisted the urge to do something along similar lines to this for about a decade – even when I finally gave in there were excuses like using 256 colours in MD201701 to hide behind rather than just going hell for leather with a no-nonsense, WSYNC-powered colour splitter – because the potential backlash from hardened Atarians to something like that is, quite frankly, terrifying! But Shadow made of sterner stuff than me and ran with it, doing every solid job overall especially when considering the small memory footprint he was working within.

Watching Five To Five (Atari 8-bit)

I’m not actually sure when Five To Five was released; there’s a YouTube video which says 1989 in the description and one visitor to Pouet commented about watching it in 1990, but there’s no date on any of the archives I usually grab Atari 8-bit files from. It’s a single-parter produced by Polish game developers Mirage Software – again according to the aforementioned YouTube description, it was put out as a preview for a game that wasn’t actually released – and features solid graphics, a brilliant piece of music by Jakub Husak and some clever use of the Atari 8-bit’s video hardware.

There’s a couple of effects of note, specifically the oscillating snake picture in the middle of the screen and a moving chessboard at the bottom; the latter is simple enough and works in the “traditional” manner which games like Trailblazer employ, having a series of triangles defining the shape and changing two colour registers for each row of squares, making the gaps wider between those colour changes near the bottom of the effect and narrower at the top.

The main effect is also relatively simple in technical terms but the implementation is what sells it; the shape of the Atari 8-bit’s screen is handled by a series of instructions called a display list and these commands can specify which mode is being used for each line of the screen, if horizontal or vertical fine scrolling is enabled and, most importantly in this case, where in memory to start fetching graphics data. There’s one of these memory selection commands for every scanline of the effect and the addresses following them are rewritten based on a sine curve. This technique wasn’t new and had already been used in the past to manipulate the display in programs like Jeff Minter’s Colourspace but the trapezoid frame around the picture adds to the overall effect, making appear to be moving in 3D.

This second screenshot is a glimpse behind the curtain for both effects that appears during the fraction of a second long pause between the display list being enabled and Five To Five‘s main code kicking in. The top of the snake picture is there without any distortion applied – the rest of the image is of course in memory after that part finishes, but the display list doesn’t have instructions to display it – so the shape of the frame more obvious and those triangles I mentioned that are used for the chessboard are visible as well.