Jingoistic flag-shagging
nemo (145) 2529 posts | |
nemo (145) 2529 posts |
I’ve fixed the wonky flag too. |
Rick Murray (539) 13806 posts |
…enough with the suspense! You’re plotting alpha channel sprites? Or none of the above but it’s being done in only sixteen lines of code? ;) |
nemo (145) 2529 posts |
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. |
nemo (145) 2529 posts |
Also, alpha channel sprites already exist. |
Patrick M (2888) 115 posts |
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: 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 |
Paul Sprangers (346) 523 posts |
Works on my Pi4, and reasonably fast too. Only the four sides don’t do their jellyfish-like movement and remain motionless. |
Patrick M (2888) 115 posts |
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. |