Workprint – October 2018

I joked in the scroller for Demo Factory 2018 last week about my X entry ending up as just a couple of parts with loads of effect presets to pad it out, but the party is only a month away now and progress on my demo really hasn’t really been… well, progressing. Part of the problem is my damned shoulder, it’s been “frozen” since the end of 2017 so, whilst working at a computer isn’t an issue in the short term, the longer sessions required for larger projects are proving problematic, leaving me in need of painkillers. I’ll have to see how things go over the next week or so and, if it’s not going anywhere fast, perhaps consider a “plan B”.

In slightly happier news I have a new toy which is pictured above. It’s a Pi1541 and is essentially a Raspberry Pi model 3B+ wearing a magical hat that, with the right software installed, makes it pretend to be a Commodore 1541 floppy drive including emulating the electronics. I haven’t had much time to test things since the hat only arrived in the post this afternoon from Australia, but the Pi’s micro SD card has been set up and I’ve tried loading a couple of demos on the C64; from what I’ve seen so far at least, it knocks the SD2IEC into a cocked hat despite being not much more expensive. It’s intended for use on my VIC 20 but I’ve been keeping an eye out for a C16 or Plus/4 although that search hasn’t been particularly fruitful, one of the latter arrived a few weeks ago but won’t even power up so is going back – which will be able to utilise it as well.

Finally, something interesting which made me happy as it floated past in my Twitter feed this morning was a YouTube video posted by Adrian Black about the C64C he was given which had spent a decade braving the elements of Oregon to the point where a colony of ants had moved in. The video itself is a heartwarming tale of a little 8-bit that could but one thing that made me smile was Adrian’s demo of choice for testing the machine was SIDBurners 7; only the Nostalgia intro appears in his video but the main menu code on that one was mine!

Watching Logo Demo (Plus/4)

Logo Demo from 1990 prominently features, as the name suggests, a large logo which was actually won in competition by a previous release of the programmer! Plus/4 scene stalwarts Muffbusters ran a 20 blocks democompo a little earlier in that year where the prize on offer for the winner was a bespoke logo drawn by group member Jeva and it was developer CSM who took the top spot with his release 20 Blocks. Two of the other three entries appear to have been lost to the mists of time, but third place was taken by a demo also called 20 Blocks which was a rough around the edges port of Moz(IC)art’s Luminous from the C64.

Along with that large, golden logo taking pride of place at the top of the screen and an area below it occupied by some blue colour splits – that routine is important, so we’ll cover it in more detail soon – there’s also a long scrolling message and the visuals are accompanied by a fairly short but still jolly piece of converted music which burbles away to itself in the background. The original SID version of the tune is credited to the Maniacs Of Noise in the scroller, but isn’t a piece I recognise even after spending a fruitless but nonetheless entertaining hour trawling through the relevant folders of the High Voltage SID Collection.

The entry for Logo Demo at Plus/4 World reliably informs us that the colour splitting routine CSM created was actually a significant piece of demoscene history for the machine, being the first time that abybody had managed to vertically split the border colour register so that there’s a different set of colours on each side of the screen. There’s also some neat multicolour character use to handle the transition of colours on the screen itself, which allows the split to swing smoothly back and forth… although I can’t help thinking that the colour tables themselves could have taken greater advantage of the platform’s 121 colour palette. That niggle aside though, this is a fun release which features a decent tune, some tidy graphics and a groundbreaking effect on the Plus/4.

Workprint – September 2018

I spent the previous weekend visiting family dahn sarf and, after a particularly harrowing coach trip home, had to spend a few days “recovering” so this post is a bit later than expected… on the plus side, I picked up a copy of Compute’s First Book Of Atari Graphics from the lovely folks at Level Up in Canterbury…

…which I hope is not too advanced for me! It even came with a hand-written page – poking out of the book in the picture above – of display lists as decimal from a previous owner which seems to have been used as a bookmark since it’s a few pages into the chapter titled Introduction To Player/Missile Graphics, one of the few places where the display list isn’t particularly relevant.

Sorry, drifted off a little there… so I’ve been working on the project I’m still not really talking about, although it’s probably safe to say I’ve been a little lazy recently; the intro is done and there’s two complete parts still waiting to be linked, but I haven’t found the time for a prolonged coding session to get any of that done and it’s one of those jobs I don’t want to stop halfway through for fear of losing my place. I also have a list of potential ideas which is coming along nicely and a couple of existing prototypes which can be improved and re-purposed so stuff is still happening.

I did find a couple of hours to doodle some code whilst away though; an interesting thread at the Plus/4 World forums mentioned using the registers $FF1A and $FF1B to scroll a bitmapped screen around in a form similar to AGSP on the C64 except without the “dead air” at the top of the screen, so I spent some time experimenting to get my head around it. The code I wrote works but this method only affects the bitmap itself so colour data would need to be moved by brute force, a bit of an ask considering the Plus/4 uses 2K for bitmapped graphics regardless of mode. It’s something to experiment with later, although I’m seeing an odd, almost FLI-like glitch in the version I wrote which added splits for a character-based scrolling message and can’t think for the life of me why it’d be there!