Bad Apple but it's 6,500 regexes that I search for in Vim
41 comments
·January 12, 2025jordigh
The tech demo that really made me fall in love with Bad Apple was getting it to run on the NES.
https://somethingnerdy.com/downloads/
Here it is running from my Everdrive.
https://inversethought.com/jordi/video/badapple.mp4
Yes, with full audio. It's about one gigabyte of data. On a system where the typical game size is no more than a couple hundred kilobytes, and your CPU only has three 8-bit registers for you to do any calculation with.
junon
Very cool. Having done a bit of NES dev I can imagine this wasn't super straightforward to make performant for the graphics, given you can typically only have a few sprites on a row before the NES starts to 'dissolve' them (not sure the term).
I wonder if it's using the background tile map for this instead of sprites, though that's also an impressive amount of graphics bandwidth.
> with full audio playback rate (44.2kHz)
The audio being so clear is also impressive, is that something that the card extends? IIRC the PCM channel on the NES isn't anywhere near that bitrate, and is also 8-bit sample size.
rav
Regarding the Vim macro that ends by going to the next line to be "replayable": You can also use the following command to run the macro once per line:
:%norm @qeieio
oh wow, TIL, I'm pretty surprised I didn't know this trick!
back when I was vim golfing the normal solution was to make the macro recursive. So you'd record your macro, and you'd end it with '+@q' (move to next line and run the macro again). Then you run the macro once and it runs over every line.
This ends up being really efficient in terms of keystrokes but in practice I think it's hard to think about and not very ergonomic, so I don't end up using it much. But it's a fun trick for golfing.
rav
There's also the no-macro solution where you just use ":%norm [series of keystrokes]" to run the given keystrokes on each line, but that comes with the added difficulty of not giving any visual feedback of what the keystrokes will do before you submit the entire line.
One thing to keep in mind is that ":%norm" will place the cursor at the start of each line, before any indentation, whereas the trick of ending the macro with "+" will place the cursor at the start of each line after the indentation. But this can be worked around with ":%norm ^@q", using ^ to skip indentation before running macro q on each line.
cryptonector
Most often when I run a macro it's to change lines matching searches, so I just start the macro with the search (or `n` if the macro doesn't do additional searches) then I end the macro with `@q` (or whatever register), then execute the macro. I don't think I've ever had occasion to run a macro on every line, though I've had occasion to run macros over line ranges (but still, all matching a specific pattern).
sltkr
For the rectangle minimization problem: your problem seems to differ from the one discussed on StackOverflow in that the SO thread discusses partitioning into non-overlapping rectangles, while your Vim project allows overlap.
I wouldn't be surprised if your problem turns out to be much easier to solve optimally.
rav
Actually, from an algorithmic standpoint it's the opposite: the minimum cover problem (where overlap is allowed) is NP-hard whereas the minimum partition problem (where overlap is NOT allowed) has polynomial-time algorithms. "An Algorithm for Covering Polygons with Rectangles" by Franzblau and Kleitman 1984: https://core.ac.uk/download/pdf/82333912.pdf
However, that's of course just an academic tangent - the theoretical results don't necessarily imply that one problem is easier than the other when you're just getting something to work for an afternoon project.
eieio
oh this is a really good point! You're totally right, I had completely skipped over the fact that the rectangles were allowed to overlap. I think I'm probably done with this project / I'm pretty happy with the solution as it stands, but I think you're right that this simplifies the problem considerably. Thanks!
vidarh
I think my attempt would've been to flood fill to create an ordered list of spans, then use roughly the same method as the Lebesque integral, using the data from the flood fill as the function.
PaulHoule
These were on sale last month
https://us.govee.com/products/govee-curtain-lights
and my understanding is that you can upload an animated GIF to it... I just added making a "bad apple" GIF for it to my Kanban board though I don't know how much memory the device has and how well I can get it to work.
(Sometimes that part where Remmy Scarlet spreads her wings still makes chills go down my spine)
nokeya
Someone definitely need to shoot Bad Apple using a kanban board!
PaulHoule
Another project on my Kanban board is a plan to big spread of Touhou characters linked with QR codes. Here's a prototype card
https://bsky.app/profile/up-8.bsky.social/post/3lbqfh7pesc2x
and the spreads I make are like
https://bsky.app/profile/up-8.bsky.social/post/3latxcwmkpk2w
I have a list of 20 that I need to fill out a little (somehow I missed Koakuma) and then I have to have my image sorter find a good set of images that fit together stylistically. (A friend of mine was talking about how RA's in dorms would make picture sets for all the rooms, seemed to me Touhou would be the ultimate basis for this)
3eb7988a1663
The parallel candidate solution generator is such a good idea, but it usually takes me a long time to realize I do not need to make the uber algorithm. Just one-more-tweak, and I know that I can make this solution work in all cases!
eieio
it's probably my single favorite trick for making a prototype performant enough! I'm delighted every time that it works.
but agree that it can be really hard to take a step back and realize that you can employ it instead of writing something "perfect"
manosyja
I remember watching the Soccer World Cup 2006 at work. I logged in my home server via ssh and could watch it in the terminal. Not enough bandwidth for something else.
perpetualchange
Roughly how long did that take?
eieio
Hi! I'm the author.
Like jchw said, this was a single-day project (although I did the writeup for it the next day).
I went from 0-prototype in one sitting; I think that was around four or five hours of work? Then I went home, had dinner, and spent maybe three hours optimizing and cleaning it up.
edit: I should say, i have done a lot of dumb things like this and I'm pretty sure it would have been at least a week of work for me 2 years ago. "making the computer do dumb stuff" is a skill like any other!
perpetualchange
Thanks for taking the time to respond, pretty impressive stuff!
jchw
From the article:
> I didn’t have the time to find a good general-purpose algorithm: I was working on this the night before weekly presentations at the Recurse Center and I wanted to present it the next day!
...
> I built this in a single day
No estimate of hours, though.
perpetualchange
My browser was apparently bugged, and it didn't show the article the first time... I see it now and am going through it. Thanks for mentioning! :)
lupire
As the author admits, it's Vim but it's not regexes. It's "searching" for screen coordinates.
It's drawing in Vim, but not pattern matching.
29athrowaway
The people running Doom or Bad Apple in different unexpected ways are such champs.
There are some really interesting ones, like running Doom on a pregnancy test.
saagarjha
Strongly disagree on that one; it was basically Doom on some random microcontroller stuffed into a pregnancy test shell.
jordigh
The pregnancy test was the greatest drama to ever hit the r/itrunsdoom community.
29athrowaway
Good point
codeguro
This is pretty cool! I like the creativity. The games this is based on are pretty good too. Danmaku are hypnotic
Hah, trust nolen to 1,000x something :))) I have used similar tactics in the past, but separately and definitely not in one day! For the interested:
- Bad Matrix (tput blocks to the terminal): https://www.evalapply.org/posts/bad-matrix/
- Animating Text Art in Javascript (print text into fixed grid, flipbook-style): https://www.evalapply.org/posts/animate-text-art-javascript/...
- oxo (format and print tic-tac-toe board to terminal, so I can regex-match for win/loss/draw results): https://github.com/adityaathalye/oxo/blob/7681e75edaeec5aa1f...
But, I mean, that Bad Apple takes the cake!
(edit: add missing link)