Dithering Makes Everything Cooler: Now Even Animated

July 4, 2022 by Elliot Williams 37 Comments

[dukope] was writing a game, Return of the Obra Dinn, with a fantastic visual style. One of the choices was to make everything in glorious one-bit color, otherwise known as black and white, and then dither it back to monochrome. You know, like they used to do on the Mac Plus.

If dithering is your aesthetic, then it makes a ton of sense to take it seriously. And it’s absolutely beautiful – check out the video below.

But what’s even more amazing is [dukope]’s attention to detail on the dithering. For instance, this post on the TIG forums details the problems and solutions when you have a dithered image that needs to also be animated. You want the dots to stay relatively constant on the object as the virtual camera pans across the scene, and that’s going to necessitate a custom algorithm. And if you think that’s cool, have a look at how the book at the center of the game is animated.

What can we say. We loved dithering before, but this post has made our love even deeper.

Continue reading “Dithering Makes Everything Cooler: Now Even Animated” →

Need A Linux Kernel Module? Scratch That

July 4, 2022 by Al Williams 15 Comments

If you have been for (or against) Rust in the Linux kernel, get ready for a Linux kernel module written in… Scratch. That’s right. Scratch, the MIT-developed language with blocks popular for teaching kids to code. We didn’t mean “from scratch.” We meant IN Scratch. The bootstrap code and Makefile is out there on GitHub.

Of course, it is a simple module and the reason it is possible is because of the scratchnative system that lets you compile Scratch into C code. If you want to look at the decidedly simple code, you can open it in your browser.

Continue reading “Need A Linux Kernel Module? Scratch That” →

Performing Magic With A Little High-Tech Help

June 30, 2022 by Bryan Cockfield 13 Comments

Doing magic with cards involves a lot of precise dexterity to know which card is where. For plenty of tricks, this is often knowledge and control of a single card or a small number of cards. But knowing the exact position of every single card in the deck could certainly be helpful, so the Nettle Magic Project was created to allow magicians to easily identify the location of cards in the deck.

The system works through the use of computer vision to identify a series of marks on the short edge of a stack of cards. The marks can be printed in IR- or UV-sensitive ink to make them virtually invisible, but for demonstration these use regular black ink. Each card has landmarks printed on either side of a set of bit markers which identify the cards. A computer is able to quickly read the marks and identify each card in order while the deck is still stacked, aiding the magician in whichever trick they need to perform.

The software only runs on various Apple devices right now, including iPhones and iPads, but the software is readily available fore experimentation if you are a magician looking to try something like this out. Honestly, we don’t see too many builds focusing on magic, sleight-of-hand or otherwise, and we had to go back over a decade to find a couple of custom magical builds from a magician named [Mario].

Thanks to [Tim] for the tip!

Linux Fu: Roll With The Checksums

June 22, 2022 by Al Williams 14 Comments

We are often struck by how often we spend time trying to optimize something when we would be better off just picking a better algorithm. There is the old story about the mathematician Gauss who, when in school, was given busy work to add the integers from 1 to 100. While the other students laboriously added each number, Gauss realized that 100+1 is 101 and 99 + 2 is also 101. Guess what 98 + 3 is? Of course, 101. So you can easily find that there are 50 pairs that add up to 101 and know the answer is 5,050. No matter how fast you can add, you aren’t likely to beat someone who knows that algorithm. So here’s a question: You have a large body of text and you want to search for it. What’s the best way?

Continue reading “Linux Fu: Roll With The Checksums” →

Linux Fu: Docking Made Easy

June 21, 2022 by Al Williams 20 Comments

Most computer operating systems suffer from some version of “DLL hell” — a decidedly Windows term, but the concept applies across the board. Consider doing embedded development which usually takes a few specialized tools. You write your embedded system code, ship it off, and forget about it for a few years. Then, the end-user wants a change. Too bad the compiler you used requires some library that has changed so it no longer works. Oh, and the device programmer needs an older version of the USB library. The Python build tools use Python 2 but your system has moved on. If the tools you need aren’t on the computer anymore, you may have trouble finding the install media and getting it to work. Worse still if you don’t even have the right kind of computer for it anymore.

One way to address this is to encapsulate all of your development projects in a virtual machine. Then you can save the virtual machine and it includes an operating system, all the right libraries, and basically is a snapshot of how the project was that you can reconstitute at any time and on nearly any computer.

In theory, that’s great, but it is a lot of work and a lot of storage. You need to install an operating system and all the tools. Sure, you can get an appliance image, but if you work on many projects, you will have a bunch of copies of the very same thing cluttering things up. You’ll also need to keep all those copies up-to-date if you need to update things which — granted — is sort of what you are probably trying to avoid, but sometimes you must.

Docker is a bit lighter weight than a virtual machine. You still run your system’s normal kernel, but essentially you can have a virtual environment running in an instant on top of that kernel. What’s more, Docker only stores the differences between things. So if you have ten copies of an operating system, you’ll only store it once plus small differences for each instance.

The downside is that it is a bit tough to configure. You need to map storage and set up networking, among other things. I recently ran into a project called Dock that tries to make the common cases easier so you can quickly just spin up a docker instance to do some work without any real configuration. I made a few minor changes to it and forked the project, but, for now, the origin has synced up with my fork so you can stick with the original link.

Continue reading “Linux Fu: Docking Made Easy” →

Blinking An Arduino LED, In Julia

June 20, 2022 by Elliot Williams 11 Comments

The Julia programming language is a horrible fit for a no-frills microcontroller like the ATMega328p that lies within the classic Arduino, but that didn’t stop [Sukera] from trying, and succeeding.

All of the features that make Julia a cool programming language for your big computer make it an awful choice for the Arduino. It’s designed for interactivity, is dynamically typed, and leans heavily on its garbage collection; each of these features alone would tax the Mega to the breaking point. But in its favor, it is a compiled language that is based on LLVM, and LLVM has an AVR backend for C. Should just be a simple matter of stubbing out some of the overhead, recompiling LLVM to add an AVR target for Julia, and then fixing up all the other loose ends, right?

Well, it turns out it almost was. Leaning heavily on the flexibility of LLVM, [Sukera] manages to turn off all the language features that aren’t needed, and after some small hurdles like the usual problems with volatile and atomic variables, manages to blink an LED slowly. Huzzah. We love [Sukera’s] wry “Now THAT is what I call two days well spent!” after it’s all done, but seriously, this is the first time we’ve every seen even super-rudimentary Julia code running on an 8-bit microcontroller, so there are definitely some kudos due here.

By the time that Julia is wedged into the AVR, a lot of what makes it appealing on the big computers is missing on the micro, so we don’t really see people picking it over straight C, which has a much more developed ecosystem. But still, it’s great to see what it takes to get a language designed around a runtime and garbage collection up and running on our favorite mini micro.

Thanks [Joel] for the tip!

Screenshot of the OpenAsar config window, showing a few of the configuration options

OpenAsar Tweaks Discord’s Frontend, Improves Performance And Privacy

June 19, 2022 by Arya Voronova 14 Comments

Not all hacking happens on hardware — every now and then, we ought to hack our software-based tools, too. [Ducko] tells us about a partially open-source rewrite of Discord’s Electron-based frontend. Web apps can be hard to tinker with, which is why such projects are to be appreciated. Now, this isn’t a reverse-engineering of Discord’s API or an alternative client per se, but it does offer a hopeful perspective on what the Discord client ought to do for us.

First of all, the client loads noticeably faster, not unlike the famous GTA Online speedup (which was also a user-driven improvement), with channel and server switching made less laggy — and the Linux updater was de-cruft-ified as well. [Ducko] tells us how she got rid of the numerous NPM dependencies of the original code – it turned out that most of the dependencies could be easily replaced with Node.JS native APIs or Linux binaries like unzip. Apart from much-appreciated performance improvements, there are also options like telemetry bypass, and customization mechanisms for your own theming. You won’t get Discord on your Apple ][ just yet, but the native client will be a bit friendlier towards you.

While Discord is ultimately a proprietary platform, we do it see used in cool hacks every now and then, like this tea mug temperature-tracking coaster. Would you like to code your own Discord bot? We wrote a walk-through for that. Last but not least, if you like what we wrote and you happen to also use Discord, you should check out the Hackaday Discord server!