MD201701 (Atari 8-bit)

January 1st, 2017 by Jason

Here comes the second release of the day (and yes, it feels extremely weird “saying” that ), this time called MD201701 and for the Atari 8-bit; raster-flavoured code and the character set are mine, with the music this time being a conversion of an old Adlib tracker song produced by Adam “Sack” Hay.

The bars are a combination of colour splits to set the base hue and sixteen possible lines of bitmap data for the luminance, so any entry in the full 256 colour GTIA palette is available on each scanline – the majority of raster bar demos only use the 128 colour CTIA colours – although I’m only using 240 in total because two sixteen shade sets of brown are so close that one might as well be skipped. There are only two bars plotted for each frame, but an “infinite rasters” routine which cycles through six buffers and rotates the palette on each pass makes things look busier than they are in reality.

Oh, the scrolling messages both have eight colour splits per scanline which was a nightmare to get timed correctly and required quite a bit of hoop jumping in the process! This release was part of the New Years Disc 2017 and organised through the Atari 8-bit section of the Atari Age forums, grab the entire package because it’s worth it!

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Refix 2017 (C64)

January 1st, 2017 by Jason

Well, we’ve finally got through 2016 and my first bit of code for the new year is Refix 2017 on the C64, a developed from scratch, expanded remake of an intro that Cosine used on games and tools during the 1990s. The original version looked like this…

…and here’s a video of the new version with a brilliant cover of the Amiga module Macrocosm handled by Andy Vaisey, the box around the screen being pushed into the upper and lower borders, a high resolution bitmapped logo and some quite frankly bonkers colour splitting on the text…

This was my third and, for this instalment, final release for the CSDb Intro Creation Competition and, although it was initially quite painful to actually get going – the colour effect was a tricky little bugger to get timed up – and needed quite a bit of late in the day optimisation to make the music fit, this really was a blast to code!

There’ll be another post about my second piece of code this year in the extremely near future, mainly because it’s another NYD contribution for the Atari 8-bit and should turn up online a little later today!

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Koalatro (C64)

December 21st, 2016 by Jason

I’ve been almost worryingly quiet for a few months – according to others rather than myself I hasten to add, I worry about me all the time – due to a mixture of illness and… well, more illness really. Normal services will hopefully be resumed once the “festive season” is out of the way and I cheer up a bit! In the meantime, I’ve been working on entries for the Intro Creation Competition at the C64 Scene Database where the primary rule is that the releases must use a single block of 16K at all times. I’ve already put out one called Clonetro on the C64CD label and today has seen the launch of the second, this time from Cosine and sporting some music from aNdy.

Koalatro is a somewhat masochistic exercise in cramming a multicolour bitmap, music, scroller (with unrolled colour splitting code that takes over five hundred bytes on it’s own) and some text into just 15K. Using a Koalapainter format picture in an intro that small whilst executing doesn’t sound too complicated, but the 10,001 bytes of data would normally eat through two thirds of the space before any code or music is included! So, whilst all the data that a Koala picture would normally require is still present, 1,000 nybbles of $D800 colour data have been rather unceremoniously packed into 500 bytes. The double speed music (the player is called twice per frame) was supplied by aNdy who originally created it for a CSDb competition a few years ago, fortunately it was pretty short because the intro needed it to be.

The scroller started out as a reasonably straight copy of one in Contribution by Super Swap Sweden – the sprite colours are split on each scanline rather than the background colour, so it only just has enough time to load two values, write to all eight and keep the side borders open if the entire loop is unrolled and all of the LDAs are absolute! As is now usually the case, I’ve pushed the source code to Github for people to prod around, but it’s not exactly the cleanest thing I’ve ever written!

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