Thinking about Uridium (C64)

Kim Justice recently posted a video about the just released Hyper Sentinel and its predecessor Uridium – I’ve been playing the former and have a few thoughts, but need to spend a little more time organising them for a post – and I’ve been making something of a nuisance of myself in the comments by, amongst other things, explaining how the background scrolling and parallax starfield work for Uridium on the C64. Whilst writing those comments I ended up coding a simpler version of my own with controls like Hyper Sentinel into the bargain, so I might as well show off demonstrate it here.

Despite the Dreadnought only being 17 character lines high that scroller is actually refreshing 21 lines of the screen from a 256 byte wide map which has been cropped down from Uridium‘s final level where it was 512 wide. The stars work in a similar way to Andrew Braybrook‘s, with two possible characters being displayed (or not if the character cell they’d be occupying as a piece of Dreadnought in it) as high resolution rather than multicolour so the points being plotted to them can cleanly counter whatever the hardware scroll register is currently up to. Braybrook’s stars are randomly placed at the start of each level whilst mine are limited to one every second character line, but it still looks okay and I could at least make it randomise the X positions.

For some reason I even got around to making the Uridimine launchers pulse using what are essentially primitive software sprites which are only being written to the colour RAM, although Rassilon alone knows if that’s how Uridium actually does it. Just for reference, where the border colour is green there’s free processing time and red indicates that my slightly clunky scroll engine is weaving it’s magic; the border also changes to pink whilst playing the music – a cover of Jason Page’s Uridium 2 loading music by Andy Vaisey – but that happens well before the visible screen actually starts so can’t be seen.

I’ve got no plans to continue this right now because it was just a doodle really, but the scroll engine started off as part of something else and the upgrades I made today might end up being passed back to that project… and I’ve literally and rather randomly just realised that what I’ve actually written here is a partial clone of Sensible Software’s Uridibad, haven’t I?!

7 thoughts on “Thinking about Uridium (C64)

  1. Interesting! In the video, is the scroll the same speed as original Uridium? Looks quicker to my ageing eyes…

    Thanks for using my tune!

  2. It’s running at the same speed as Uridium yes, they both pull eight pixels a frame flat out. Mine can go faster with a bit of reworking and I’d be surprised if Uridium couldn’t do the same, but imagine how hard it’d be to avoid collisions…!

    And the music fits rather well, doesn’t it? =-)

  3. “My God – It’s full of stars !!!” Beautiful Cover of Uridium 2 by Andy Vaisey – That man is a Genius :-> Hope you continue with this Project and make a nice Game with it :->

  4. Like I said in the post, this isn’t a project; it’s more a practical demonstration of how the stars work for my own benefit. I don’t plan on doing anything more with it even if the current version has basic sprite mapping sorted out as well…

  5. The ‘current version’ has sprite mapping also? The next version will have? And so on. and so on, etc., until… GAME!! 😉

  6. The sprite mapping is just part something it’ll need in it’s not-Uridium form; getting the attack wave driver right is the tricky bit, I have a few ideas on how that should be done but not ones that’d work with the current sprite handler.

    I do have a Uridium-esque engine in the work folders but that’s another proof of concept and isn’t for the C64…

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