Eagles Dare (C64) released

It’s “busy season” again, so there’s yet another entry into the CSDb Intro Creation Competition to mutter about! This time it’s called Eagles Dare, has got code and graphics by yours truly – the picture is mostly wired, but I did some work to make that happen and added details – and aNdy handed in another great tune. The memory footprint is $0400 to just before $43ff so this is a 16K intro.

The unusual feature of this one has to be the scrolling message, it uses Extended Background Colour Mode which limits font use to the first 64 characters (the upper two bits of the character code are used to select one of four background colours) but, rather than a fixed character set, the scroller has a 39 character buffer which is scrolled along the line, recycling whichever character falls off the end for the next. This means that any character from the C64’s upper or lower case ROM font can be selected, although the embedded commands for that and those used to select background and foreground colours take quite a bit of space and there’s not much room for actual text in this one!

2 thoughts on “Eagles Dare (C64) released

  1. Clever scroller. I’ll delve around the code sometime. If I’m feeling brave. Maybe

  2. The colour split stuff is fairly simple – it’s not much different to what you’ve done in Funky Stars, just changing four registers per line rather than one – so the fun part is the way it handles the characters and cycles them around.

    Have a look around line 383 in the source, there’s an LDY #$12 which is fed to $d018 a few lines later to select the work font at $0800; change that to LDY #$14 to use the upper case ROM font at $1000 and you can see the thirty nine characters cycling around on the line. As one moves off the left it comes back on the right and, in the redefined font, a new character definition is copied into it.

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