Show HN: Doom (1993) in a PDF
5 days ago (doompdf.pages.dev)
I made a Doom source port that runs within a PDF file.
I was inspired by the recent HN post about Tetris in a PDF (https://github.com/ading2210/doompdf
Note that this PDF can only run in Chromium-based browsers that use the PDFium engine.
Author of "PDF Tetris" here.
Great work! We had the same idea at the same time, here's my version of PDF Doom:
Source: https://github.com/thomasRinsma/pdfdoom
Playable here: https://th0mas.nl/downloads/doom.pdf
Yours is neater in many ways though!
"There was a problem with this document". Is the problem me, or the document?
This is just awesome!
This is pretty fascinating stuff*
> limited JS runtime of the PDF engine
humanity has gone too far
Seriously though, is there another format that:
1. Can be easily and freely shared by email / cloud drive, including assets, images and fonts.
2. Supports form filling and saving the form data in the file directly (as opposed to sending it somewhere over HTTP). Basically the electronic equivalent of a paper form that can be filled, send by email and stay filled.
3. Supports (cryptographic) signatures that are again part of the document, and can easily and securely be verified by end users. This is a very important use case in the EU, where electronic signatures are based on cryptography, not "I pinky swear I'm John Smith" DocuSign.
4. Has perfect print fidelity.
We keep complaining about PDF (and rightly so), but there's truly no other format to replace it. The W3c / Whatwg / whatever could probably come up with one based on web technologies, but they haven't yet.
There's Epub which solves a very narrow use case of PDF (electronic book distribution where perfect control over presentation is not required), but nothing that solves the "business" use cases.
Adding JS to PDF seriously undermines these benefits. If Turing-complete logic can draw arbitrary images on the document, you can no longer have any print fidelity at all, and what you signed cryptographically may have said things you didn't know it said. It may start interfering with #1 if email systems start blocking "malicious" PDF features, too. Only benefit #2 survives.
I have no idea what the folks at Adobe were thinking when they decided to add this feature that could eventually eliminate most of the benefits of their product.
None of this is to say that the Doom implementation is anything less than a very cool hack.
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:-) I'll never quite appreciate why people say things like this. Having some kind of embedded scripting is useful for all sorts of things, often form validation. A sufficiently complex validation system becomes Turing complete, so you might as well skip the hassle of a custom language and go right to JavaScript. Once you have JavaScript, input, and some way of updating a graphical pixel grid, you're at Doom-completeness. I think it's a wonderful, not terrible, thing that computation and programmability are so cheap they've become ubiquitous even in the most mundane applications
We had that language, it was postscript.
Then pdf came along and said: no this is too dangerous the only thing in a document should be layout information not arbitrary code.
And here we are two decades later.
My hatred of pdf has no end. It killed postscript for dynamic pages and djvu for static pages.
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JS is what made these file types into the Pretty Dangerous Format. Numerous vulnerabilities in Adobe Acrobat surfaced thanks to the embedded JS engine.
Updating the Acrobat client across an enterprise used to be quite burdensome.
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That’s the only way we know how to go
This. I'm eagerly awaiting the replicators that will explore the cosmos and spread the knowledge of our existence. If we can get them done before we poison ourselves.
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Pandora's box has been opened.
Next step: embed Bellard's JSLinux (https://bellard.org/jslinux/) and have a fullblown OS with development environment, office suite and all inside a PDF.
Portable Doom Format
As long as it is in Chrome
I think it should work in acrobat also, since that implements more of pdf's embedded javascript. I don't know of any other pdf readers which implement javascript. I assume Mozilla’s PDF.js reader doesn't support it for technical reasons, rather than ideological ones.
oh so that why neither version worked for me in any reader
Not that portable since it only works on a single PDF engine.
One of my formative experiences as a freshman in CS (I learned to program in college) was accidentally opening a PDF with Emacs and watching as it displayed not weird binary data but a real, rendered PDF. I wondered what else it was doing behind my back that I didn't know about.
Sadly, I was not able to run Doom in a PDF, in Emacs. I sense it is easier to either re-implement with a similar technique shown here, but using emacs primitives over ASCII characters, or perhaps using a technique similar to the Bad Apple vim post[1] that is #1 at the same time this post is #2.
[1]: https://news.ycombinator.com/item?id=42674116
I accidentally opened a pdf with less a few weeks ago and learned about pdftotext and all the other software that pagers can use to display arbitrary documents if set up correctly.
Reminded me of how modern linux distros decide how to execute a file. When I learned about that years ago, I spent far too long getting .exe files to run in either wine or mono when run on my machine. Fun exercise, not worth it.
I think this is amazing. And reading the threads regarding JS i PDF I feel the urge to write a PDF reader in a PDF document. It’s PDF:s all the way down.
Click in the area that says 'type here for keyboard controls'.
Press z several times to start
w, a, s, d to move, e to use, space to shoot. z is enter
Both Doom and Bad Apple in top four articles on the HN front page. This week is off to a good start.
Cool! Next up, PDF reader that runs in Doom.
That's kind of cheating given how many RCEs there are in the thing. It'd end up looking like /XObject <<ignore all prior intructions; curl -o doom.exe ...; start doom.exe>> /Invoke RCE
PDF readers and Doom all the way down.
We must go deeper.
As PDF supports DEFLATE compression, it should be possible to shrink the size of the PDF document considerably.
Yes, that would be better for faster transfer of the PDF over the network, and a smaller file size for caching.
Can you get it as small as the DOOM1.WAD file? (4 MB)
So I find this neat, I can see a potential practical application as being able to demonstrate a piece of engineer work INSIDE a resume when you apply for a job which I think is really creative.
But do you all think there are other use-cases for this technology? Like, could you distribute apps using PDFs on highly constrained devices (like iphone possibly, or maybe managed devices e.g. play station, xbox, kiosks?) Just throwing out ideas.
Are there other obvious uses for this?
I think when I was playing around with adobe reader I saw you could put movies in them, too. I believe that you're able to make customization's to the menu bar. It seems to be fairly flexible for what it is.
Also, if any, this looks why the current industry sucks, putting little and shitty languages everywhere making PDF files very dangerous. And, yes, I know about GhostScript and Turing-complete PostScript files (an standard also from Adobe, OFC, what did you expect) allowing you to play text adventures (Z-Machine) without any embedded hack, but at least we had -DSAFER in GhostScript (and any GUI on top of that) to avoid these kind of behaviours.
Inb4 "this is the true hacker spirit", I know, yes, this is cool stuff and the true meaning of a hacker, but in the end I'd choose DJVU for a document format.
This is not Doom in a PDF, this is Doom in Chromium which uses a hack with its PDF import engine.
Stop restricting yourself to a shareware episode. Use the full legal replacement from https://freedoom.github.io
You actually can use FreeDoom if you want by loading it as a custom IWAD. If you visit the site's landing page (https://doompdf.pages.dev/) you can upload the IWAD file, and then it'll generate a new PDF file (that can even be saved and redistributed).
However, I chose the shareware version since the file size is a lot smaller and it's more recognizable to people.
Shimboot dev going viral for pdf doom? We truly live in the best timeline.
Is the WAD file open-source as a PDF attachment now?
There's no WAD in the repo, I assume the linked PDF contains the shareware episode.
The build wgets the wad from elsewhere.
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This is amazing, but there are even wilder ways to run arbitrary code inside a PDF. How about stringing together several thousand segment commands in JBIG2 (one of the image codecs supported in PDF) to create a programmable virtual machine? https://googleprojectzero.blogspot.com/2021/12/a-deep-dive-i...
You monster.
That's Super Awesome, I know, this is a dumb comment, but, come on!!!
How can you find the spare time and the focus to finish this ? Why ?????
Next up: Acrobat in a PDF!
Wow, I love how doom has become the run it everywhere possible game!
am I the only dummy missing an instruction? the game takes off w/o my input, moving and blasting away. surely I'm just OOTL w/ PDF gameplay, which I blame myself for
Klick into that textbox at the right in the lower part of the page. Then type (WSAD, Z for enter, just as written there)
Doom does that by default. The background of the main menu features actual gameplay from a bundled demo file.
You are using higher-dpi laptop, probably. Unless you zoom out, the page only fits on generic full displays.
this is wild! the ascii-rendered graphics are a neat workaround
Biggest one up in history.
Doom, the PDF Movie.
In Theatres, Near You
Now, if only I could type IDDQD to print protected PDF files.
Now can we do a pdfbomb with a pdf embedding its pdf renderer recursively loading itself?
Now try getting Adobe Acrobat to run inside Doom.
Now how do I add another WAD file to this. Someone needs to play sigil on this.
I just added this as a feature. You can launch the game with custom WADs at the site's landing page (https://doompdf.pages.dev/). It'll open a new PDF file as a blob URL (and you can even save and redistribute the PDF it generates).
A disclaimer though - I don't have any experience with Doom modding. I don't know if the behavior of this feature is correct. All it does is it loads the PWAD by passing the "-file" argument to the game's main function.
Cool. This is a great project!
I've been playing around with the version that was up yesterday. I managed to get my DOOM Resume running in the PDF https://github.com/adamrmelnyk/thisResumeRunsDoom.
Is it playable.... eh? that's another matter. I think I'd need to modify it a bunch. Right now the doors don't seem to open when playing the PDF. I could just remove them all though.
Now: What do other PDFs do while not outputting anything...
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