They manage to run “Doom” inside a PDF file, and it works better than you’d imagine.

Rock was launched over 30 years ago but remains relevant thanks to a tireless community modders who decided to take it to the craziest environments and devices. id Software’s legendary first-person shooter can not only run on graphing calculators, ATMs, price scanners and a host of unusual hardware, but now it has a version works inside a PDF file.

The work in question is the work of ading2210, a student who was inspired by other similar projects and created a version Rock it is in a PDF file and can be downloaded even to play without an internet connection. All you need is a Chromium-based web browser, such as Google Chrome, Brave or Microsoft Edge.

PDF files are widely used for exchanging documents containing text and images, but their capabilities are not limited to displaying static information. The person responsible for this project explained that the format supports JavaScript through its own separate libraryand that some modern browsers that allow you to open this type of file implement this feature.

The young man shared the code of his creation on GitHub with additional details about the procedure. If you just want to try Rock in PDF you can do it directly from the Internet using this link. If you prefer to have the game on your computer, you just need to download it from the source; It weighs only 6MB and you can launch it from a compatible browser and play whenever you want.

How are the graphs displayed? Rock inside a PDF file?

Graphics implementation Rock in PDF file – this is one of the most striking and remarkable moments of this project. As ading2210 explained, other similar proposals have used separate text fields that are activated and deactivated to create individual pixels. However, he emphasized that this approach unviable in this case, because the game’s resolution (320 x 200) would require thousands of text fields to be turned on and off per frame.

To solve this problem, the developer chose use ASCII characters with 6-color monochrome output. This allowed you to have a separate text field for each line of the screen, making graphics and menus legible enough for gaming. The method is not the most beneficial in terms of performance, since updating the text supporting the graphics requires 80 milliseconds per frame. Regardless, the end result is much better than we could have imagined, and in our experience we’ve seen peaks of up to 40fps.

What about control? play Rock From the PDF, you have two options: use your mouse to click the commands that appear on the screen (Escape, Use, Forward, Back, Left, Right, Enter, and “Shoot”) or use the computer keyboard. The creator of this port included a text box where you can click buttons that allow you to perform actions. This:

• WASDto move forward, left, backward and right respectively;
• Shift + WASDrun;
• Zto press Enter;
• questionto use as an Escape key;
• spacefire;
• Mto open the map;
• ANDuse;
• Numbers from 1 to 7to change weapons.

Thus, DoomPDF complements the long list of examples reality Rock and the creativity of their fans.