Jingoistic flag-shagging

I’ve fixed the wonky flag too.

…enough with the suspense!

You’re plotting alpha channel sprites?
You’ve specified a new “animated sprite” format that plots itself automatically?
Both of the above?

Or none of the above but it’s being done in only sixteen lines of code?

;)

This is a rebuild of David Braben’s 1987 “Union Jack” Archimedes demo.

I’ve updated it to run on modern ARMs; in a window when run from the desktop; improved some of the wonky¹ code; and fixed the vexatious vexillology (so that it’s nearer to the actual Union Flag than the Georgian Naval Ensign).

I’ll release it later today when I’ve made it smaller – it’s a bit bloviated.

¹ Like early Computer Concepts code, the lack of familiarity with ARM means there are weird constructions – and like CC code there’s a blindspot regarding PC-relative addressing, which is interesting. I haven’t changed the code to use MUL/MLA though, the LOG/EXP approach is interesting to keep, and the table-driven “small integer divide” also. Admin, not re-engineering.

Also, alpha channel sprites already exist.
Animated sprites are now possible via IFC (flashing colours!).
It’s currently 58K and takes a 140K wimpslot, but I can do better than that at no detectable cost.

I just saw this thread. Coincidentally, this demo is a bit like something I coded recently for fun.

Here’s a video of it in action:
https://mastodon.me.uk/system/media_attachments/files/110/458/695/214/406/849/original/a89ebf2cccd9cfd1.mp4
mastodon link:
https://mastodon.me.uk/@dusthillperson/110458695597981108

Here’s the source code: https://github.com/dusthillresident/JohnsonScript/blob/master/example_programs/cementmaster.txt

Here’s a BBC BASIC version that might work, I haven’t tested it on my Pi: http://dusthillresident.ddns.net/folder/files/quickupload/ripple_quads_bbc_basic.txt

Here’s a BBC BASIC version that might work

Works on my Pi4, and reasonably fast too. Only the four sides don’t do their jellyfish-like movement and remain motionless.

Thank you for trying it! I’m glad it works. That issue is because it doesn’t clear the screen before redrawing. I actually did that deliberately because I don’t know how to do double buffering on RISC OS (it always seemed extremely complicated, requiring lots of magic *fx commands) and I assumed it’d run slowly enough for the flicker to be very noticeable and unpleasant.