Hackaday Links: December 13, 2020

Our sun has gotten a little flustered these days, and it may have rewarded us The best screensaver image ever taken. The incredibly detailed image of sunspots was taken in January by Daniel K. Inouye Solar Telescope, a 4-meter-long instrument with adaptive optics that can photograph the sun from near-infrared to visible wavelengths and resolve surface detail up to 20 km. The image, with its distinctive “Sauron’s Eye” appearance, shows massive convection cells surrounding the dark sunspots; The accompanying animation shows the movement of the plasma along the tormented lines of the magnetic flux causing the formation of the sunspot. It’s great to watch, and even more interesting to think about the technology used to capture it.

With the dust surrounding the youtube-dl DCMA removal by GitHub fresh on the minds of the open source community, GitHub Universe 2020 was An interesting discussion on preserving open source software projects This is worth seeing. Focus on the challenges youtube-dl moderators face in keeping the tool working, and the impact their efforts have on the people and groups that depend on it. To underscore this point, they showed a researcher with Human Rights Watch who relies on youtube-dl in her work, and they made it very clear that keeping up with all the API changes that constantly disrupt open source tools like youtube-dl makes the moderators role much more important.

Speaking of GitHub, here’s a cool and spooky new tool: Dipex, Password pixel removal tool. Developer Sipke Mellema noticed that his company often used pixels to hide passwords in authentication, and asked if he could undo the process. He wrote an article Describe the pixelation process using a linear square filter and its method of attacking it, which includes creating a De Bruijn sequence with the same font, text size, and colors as the original document and entering a screenshot of that and the pixel password into the tool. We suspect it will only work with a subset of opaque passwords, but it’s still pretty smart.

This is the season of Advent calendars, and People at QEMU have posted their data. Open each of the 24 chapters on the calendar and you’ll be rewarded with a downloadable QEMU CD image that delivers something fun. Minesweeper, a ray-tracing tool that can fit into the boot loader, and of course Conway’s Game of Life. A GW-BASIC photo caught our attention on the third day – it brings back some memories.

For anyone who has ever watched the Pixar movie and wondered how all of this animation worked, here’s to you Great lesson in making art with mathematics. The video is from Inigo Quilez and covers the basics of rendering images with Raymarching SDFs, or autographed distance functions. At first, it looked like it would be a bit like Drawing an owl, But his description of the math involved and how each animation component is just another formula is cool. What’s more, there is Real-time display tool Where you can check and edit the code. Sadly, the changes you made made things worse, but playing with it was fun and rewarding. Check out the video after the first half!