We’re running a little late for a second time and your correspondent can only apologise to his regular readers whilst seriously considering a change of the “scheduled” day for these posts to Friday in future whilst hoping to avoid at least some of his “scheduling conflicts”… but in the meantime, here’s another Code Notes look at a couple of C64 crack intros which were created by self-taught, bedroom programmers during the 1980s.
First up is one of many intros used by Ikari a cracking group whose base was the United Kingdom; this example was developed by a member called Excell in the middle of 1988. Although it’s nicely designed there’s actually just effect here; the colours passing through the text are produced using an inverted font so the set pixels are black whilst the unset ones are in this case horizontally expanded hardware sprites with the priority register set to put them behind the characters. The sprites are, understandably, being recycled for each row of text and there are some colour splits taking place to make things a little busier visually.
The second intro is an early 1988 offering from the Danish group Jewels which has eight hardware sprites making up a red logo bouncing around on top of a character-based scrolling grid. Parts of the lower text use a “colour wash” effect and the scrolling message is bouncing up and down courtesy of an FLD routine. Here as with the previous intro, the music was composed by Thomas “Laxity” Petersen, a remarkably prolific musician with over two hundred tunes to his name which is an impressive body of work even when before we consider the high level of quality throughout that collection or indeed the author’s petulant whining about how “Commodore and Jack Tramiel made it impossible for [him]” because he didn’t want to put any effort into learning!
Continuing the “grid” motif is a second entry from Ikari in 1987, this time developed for them by a member of Commando Frontier; it features another sprite-based logo bouncing around merrily over a grid which is this time static, and there’s a scrolling message which is again reliant on the technique of inverting the font so that changes to the background colour will produce an effect through the characters. There isn’t any music in this intro, but adding some wouldn’t have been particularly difficult since your correspondent is assuming it to be reasonably efficient on both memory use and processor resources.
The author will no doubt complain that some of the developers behind these releases were European but, since their documentation didn’t offer any magical path to programming that wasn’t available for people like the author if they actually looked, that argument can be easily debunked without effort. Similarly, these releases hail from 1987 and 1988 but, despite being outside the author’s pointless, self-referential 1984 to 1985 window, the people developing them didn’t have any vastly improved resources to learn from.
 Colour wash effects have each character on a line at a different point in a colour table – usually fading up and down in luminance – which is usually achieved by scrolling the colour memory to move each byte into the colour RAM cell next to it and adding a new value at whichever end said scrolling is moving away from.