While it was fun making last year's low-budget Xmas Demo, the time has come to... push the button. Nvidia has discontinued the Nano, so we considered our options before doing anything creative. Or anything at all, really. The result was a given: If it was gonna be 4Kp60, it had to be the Nvidia Jetson AGX Orin [1] again. The Jetson Orin Nano Super just isn't powerful enough. So: Beef up last year's shaders to 4K and add lots of details, replace the crap shaders with better ones, and be done before summer is over. Shouldn't have wasted the summer in the sun, then. Damn.
As always, The Xmas Demo runs in 60 fps on the target hardware. We're not lamers this year, either. The 4K summer preview, while entertaining, was actually 1080p scaled to 4K due to a minor mishap in the lab. Didn't discover that until we started working on the demo. Shoot. Well, at least you can be fairly confident that this year's demo is real 4K. Heck, we'll mail you the high-res mp4 if you want it, as long as your mail system can handle 3 GB files. Or just compile the code yourself. It runs on everything: Linux, Windows... and Mac. In Sjur's lab. We also heard rumors that Intel might actually make a useful GPU soon. Wasn't this year, either.
Never change a winning team! Like last year, we used music by C64 and Amiga legend Chris Huelsbeck. The track is called "The Agency - End Credits" from the album "Dressed to Chill". Check out the links below. We added sound bites and voice-overs from Tron, The Prisoner, American Psycho, well, the usual array of subversive sources. Due to unforeseen circumstances, we had to mix it in that program which shall not be named [2]. Relax, we used a proper 300B amp because it sounds awesome. We're getting older and the gear is getting more expensive and obscure. Nothing new under the sun.
This is the 7th Xmas Demo since 2017. We added a couple of pop-cultural references to that number, along with all the usual tomfoolery we do every year. With almost unlimited compute power comes the responsibility to waste it all on awesome looking effects. Hmm, that didn't sound right. Anyway, it's C and GLSL so it's quick as a flash and readable and comprehensible. Like all good C code. We stand by our articles, books, videos, lectures, flyers, buttons, pins, t-shirts, and tank tops about this subject.
To quote the demo: "Always recycle! And don't waste energy! Don't be a pythoneer [3]."
Same as every year. Don't get it? Thought not. As always, have a great Xmas! 
The Agency - End Credits [bandcamp.com] by Chris Huelsbeck [patreon.com].
Used under a royalty-free license.
Voice and noise samples from Tron (1982 film).
Voice samples from American Psycho (2000 film).
Voice samples from The Prisoner (1967-1968 TV series).
Archive: xmasdemo_data_2025.zip (browse)
| File | Title | Artist |
| data/buttoff.png | Buttoff | Corneliusen |
| data/button.png | Button | Corneliusen |
| data/smallbike.png | High Wheeler | Public Domain |
| data/icarus.png | Project Icarus (dark) | Unknown artist |
| data/icarus_br.png | Project Icarus (bright) | Unknown artist |
| data/iffybook.png | Necronomiffycon | Dodgy artist |
| data/chrisr.png | Chris (right) | From Bandcamp |
| data/player.png | Turrican Player | From Mobygames |
| data/turrican.png | Turrican Logo | From Mobygames |
| data/amiga.png | Amiga 4ever <3 | Commodore International |
| data/secret.png | Secret Frame | From Collider |
| data/sbfist.png | Speedball Title | From Mobygames |
| data/pinkpig.png | Animal (Pig) | Suspicious artist |
| data/motion.png | Triumph Motion Pictures | Triumph |
| data/bug.png | Triumph Beetle | Triumph |
| data/stooge.png | Stooge | Ringstad |
| data/igbanner.png | Barely a Ripoff | Doubtful artist |
| data/tombstone.png | The End | Dubious artist |
| data/moi.png | Ministry of Information | From Wikipedia |
| data/sig.png | Signature | David Lynch |
This demo uses the V73D Engine [github.com] by Sjur Julin. It's a pure C and GLSL project with a minimum of dependencies, so it will compile and link with no fuzz. You will need it for building the Xmas Demo yourself. Both V73D and the Xmas Demo runs on Linux and Windows.
An assortment of shaders from ShaderToy [shadertoy.com] have been modified and used. Important! The shader files in the archive have been stripped of comments and recommented where we have changed things. Check the ShaderToy source for the author's intent. It's very helpful.
Archive: xmasdemo_src_2025.zip (browse)
Note: Since we couldn't find the original shader at publishing time, Midnight Sun is uncredited. Sorry. It's fixed in the table above and the source code.
The high wheeler is a reference to The Prisoner as usual.
There's HCF instead of STOP on the button. It means "Halt & Catch Fire", a legendary CPU instruction that causes a deadlock. And possibly a fire. You should have grown up in the 70s like us.
The voice saying "All programs have a desire to be useful" is the MCP in Tron.
Icarus is from Dirk Gently's Holistic Detective Agency (2016-2017 TV series) that's based on Scott Adams' books. Dirk is Project Icarus. And the logo is just great, for a reason that might not be obvious.
The pig should be recognized by Pink Floyd fans.
The character on the book is Iffy, not to be confused with another beloved children's book character from the Netherlands.
It's the 7th Xmas Demo. "The Xmas Demo Awakens" is a reference to the 7th Star Wars film.
Secret number: The pattern in the upper right corner is morse code for "73", the unique Sheldon prime. Duh.
In case you've been living in a cave for 35 years: Chris Huelsbeck made the music for Turrican (1990 game).
Had to have an Amiga logo somewhere. Purists will notice that it is the latest iteration.
2716057 is Bender's serial number. He is a character in Futurama (animated TV series).
The voice saying "I'm just a happy camper. Rockin' and a-rollin'." is Patrick Bateman in the end sequence of American Psycho. Another film that's better than the book.
Secret frame: That archaeologist hates snakes, right? We have no love for snake-themed programming languages. It sort of ties in with the scroller in Twofield System.
"Bite my shiny metal ass" is Bender's catchphrase in Futurama.
"Cult of the Xmas Demo" is a reference to the 7th Child's Play film and also a reference to season 7 in American Horror Story. It's called... wait for it... Cult.
It looks absolutely fabulous in 4K and with high (or was it low?) Nostromo-factor. We ruined 2023's MSAA-based rendering after a series of unfortunate events, so we made "I can't believe it's not MSAA" instead.
The scrolltext is a verse from the Pink Floyd song Us and Them.
The voices saying "- Ever since he got that Master Control Program set up, system's got more bugs than a bait store. - Well, you have to expect some static." is Alan and Gibbs in Tron. For that enigmatic touch.
"A still tongue makes a happy life" is from The Prisoner:
The Triumph Motion Pictures logo and the souped-up Beetle was used in some Triumph 90s productions. Find them here. We didn't forget! As we said last year: It's not an Xmas Demo without a spaceship. The Beetle counts as a spaceship. Watch the Superhero video.
Greetings to Amiga groups we have knowledge of, in one way or another: Triumph, Scoopex, No Limits, New Wave, Cryptoburners, IT, Spaceballs, Offence, Razor 1911, Crusaders, Kefrens, Cinefex Design.
A stooge may appear in the upper right corner.
It just looks incredibly pretty in 4K. I advise you to check out the original version on ShaderToy if it works. There are no similarities left, and the code is quite different. We still credit the original author, otherwise we'd never have come up with it. It's discussed in that book nobody has read.
The ignorantus.com banner might look familiar... if you're 5 years old.
The long voice sequence is from the intro to The Prisoner. We ripped it from the 2015 remastering of Iron Maiden's album The Number of the Beast. It sounded better. Also, the story of how Maiden got the rights to use it is entertaining. Check Wikipedia.
"Apply yourself" is our favorite quote from Breaking Bad (2008-2013 TV series). Here from the Xmas Demo 2023 where Walter White was replaced by a stooge to avoid any issues:
According to Wikipedia, "Turtles all the way down is a humorous expression of the problem of infinite regress". They can make everything sound boring. Anyway, Hawking uses it in a humorous sense in the beginning of A Brief History of Time (1988 book). Read it. We also like Terry Pratchett's turtle theory.
The scrolltext is a verse from the Pink Floyd song Breathe.
The whole part got kinda depressing, so we added some extra fire and a tombstone at the end to... yeah, that didn't work out at all. Issues like that should have been sorted out in the weekly design meetings that nobody attended.
A trip down memory lane. Careful, it might glitch.
The voice saying "Well, you guys know what it's like. You just keep doing what it looks like you're supposed to be doing, no matter how crazy it seems." is Flynn in Tron.
The Ministry of Information logo is a reference to Brazil (1985 film).
We added a dedication to legendary filmmaker David Lynch who unfortunately died this year.
[1] Good news! Nvidia just released DGX Spark [theregister.com] with even more awesomeness. Awesome price, too. Ouch.
[2] Audacity. Ouch.
[3] We use this word in the derogatory sense. See lamer [wiktionary.org].
This looks like a much nicer shirt than the crap ones we usually make. Haven't ordered from them yet, so buyer beware: Project Icarus T-shirt [teepublic.com].
Technical comments are welcome. Contact information is available here.
If you have a problem with the article text, the video, or the code in any way, please watch this informative video:
Remember to appreciate this XKCD strip titled "Replication Crisis" [xkcd.com].
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Item: Newspaper from Paperboy (1985 arcade game). License: Screenshot via MobyGames