Watching Contribution (C64)

Over thirty years ago, Contribution by Super Swap Sweden was released and competed in the Rebels and Agile copy party’s demo competition, taking the first place and beating entries from other C64 luminaries including Science 451 and Agile in the process. That probably shouldn’t come as a surprise since the group behind Contribution would soon go on to merge with Thundercats to form Horizon, but this particular release before that merger had a fairly specific impact on me personally which I’ll get to in a couple of paragraphs.

Including the humming intro at the start there are six parts with each showcasing a couple of nifty routines; there’s some “3D” raster bars with a bi-directional, colour split ROL scroller (the latter was the inspiration for my own routine in Koalatro over twenty eight years later), another ROL scroller with some vertical motion – making for some odd but interesting diagonal text whilst being surprisingly hard to explain – running over a thirty two point, bitmap-based plotter, a DYCP scroller which has multiple speed and wave presets, a picture mover using 56 sprites per image together with an eight sprite scroller which both seem to be ignoring the borders and to round things off there’s a pre-calculated logo animation and another sideborder scroller.

I don’t remember having seen a DYCP scroller before this demo so that was doubtless fascinating to me at the time, but what I found to be the most impressive part of the show was seeing the series of ESCOS-style, 56 sprite pictures swinging around the screen and into three of the four borders with the scroller taking up the remaining one. I barely understood what was happening in a regular ESCOS routine or indeed the enhanced ones in things like the NWCUG demos so seeing pictures whizzing around freely like that was sheer magic!

Contribution has a special place in my heart; it was the first Super Swap Sweden demo I ever saw – one of the earliest demos I mail traded with a contact in fact, and it arrived with one of the other entries from the same competition which is on my “to do” list – but that doesn’t change how impressive it was and, in some senses still is. It might seem relatively simple now even if the comparison were to be limited to the developers’ later output, but it still holds together very well and, along with the other Super Swap Sweden demos, is certainly worth watching.

Watching Little Demos (Atari ST)

“Robb says wow!” We’re going back to the early releases of Atari ST legends The Exceptions for a quick squint at the two demos which followed on and indeed evolved from Readme.prg – this would all lead to The B.I.G. Demo in early 1988 but that’s probably a post for another time (along with quite a bit of recording since the name isn’t exactly ironic).

The first of these two releases is Little Sound Demo and the large scrolling message with palette rotation in the background returns for another outing, but this time the picture has some raster bars through the TEX logo instead of the background and some decorative palette rotation around the indicator saying which piece of music is currently playing. There are twelve tunes in total which are mostly conversions of Rob Hubbard’s work from the C64 – hence the picture of a Breadbin getting lamped in the back of its “head” by the music emitting from an ST – with a couple of pieces composed by new group member Mad Max who also did the conversions and wrote the music driver.

That handle might not be familiar to those outside the Atari ST scene, but a few folks might recognise his real name Jochen Hippel since he was the musician for several games including Wings Of Death and the ST versions of Turrican and Turrican 2. He also released an album mostly consisting of reworked versions of his game tunes called Give It A Try and I’ve got a copy of that CD knocking around… somewhere?

Little Color Demo continues where its predecessor left off in expanding on what Readme.prg did and wedging more colour and action into the display like the barrel scroller between the two pictures of Rob Hubbard, more palette rotation under the tune list and some serious colour splitting on the lower scroller. One feature that wasn’t carried over from the previous release however is Mad Max’s compositions, there’s only eight tunes in this demo and everything is a Hubbard cover apart from the version of Axel F.

It’s fascinating to see the code mutate and evolve as the coders learnt more about their machine of choice but, whilst the bespoke music driver and converted tunes are a major plus, the hyperbole around them is probably pushing things a little; the tunes are good if sometimes missing elements – or large chunks in the case of Flash Gordon and International Karate – but the sounds being used don’t really hold a candle to their C64 equivalents. Rob himself was already doing Atari ST tunes in 1987 including a reworked version of Human Race tune 4 for Goldrunner, which was coded by the well-known game developer Steve Bak who, by a sad coincidence, passed away a couple of days ago whilst this post was being written.

Looking at these two as a whole, as with Readme.prg they were a little underwhelming to the teenage version of me waiting for the Atari ST to really offer stunning graphics and sound – hearing those covers of older Rob Hubbard tunes was cool but nowhere near enough to entice anyone away from the C64 in that respect – but the early works from Mad Max did offer some promise for the future and both demos are significant milestones in the Atari ST’s scene history.

Watching VSP&IK+ (C64)

We’ve got another piece of C64 scene history today, the Mean Team’s VSP&IK+ from 1987. This is another of those demos from the “Wild West” period when programmers were as much concerned if not more so with getting their latest creations out there and the name is pretty much self-explanatory; the IK+ part comes from the music by Rob Hubbard and Paul “Dokk” Docherty picture which were both being taken from the game of the same name, whilst the VSP refers to it being the first instance of Variable Screen Positioning, a hardware “feature” similar to but much harder to implement than the more common Flexible Line Distancing – FLD to its friends – which was in common use around that time.

This technique is sometimes referred to as DMA delay because that’s essentially how it works, waiting for a badline where the C64 fetches screen data and fooling the VIC-II into waiting for a fixed amount of cycles before that fetch actually takes place by setting the vertical scroll register to a value that won’t see it happen, then changing back to one where it will later in the line. One cycle equates to the width of a character so waiting five cycles will push the screen right by that many characters and it’s possible to travel an entire screen width, with the data wrapping around onto the start of the next line, something this demo masks by changing the attribute data. VSP-based scrolling is how games like Mayhem In Monsterland can move their backgrounds so quickly.

I remember seeing VSP&IK+ for the first time on a friend’s C64, casually thinking “oh that’s nice and smooth” in passing as it started up and the picture slid smoothly in from right to left and then staring in disbelief as it snapped back in the other direction at far too great a speed to merely be a double buffered bitmap scroller – we already knew about FLD and understood how it worked but this was nothing short of witchcraft at the time! It still makes me smile now despite knowing how the routine works and having my own examples.