Homebrew CPU Gets A Beautiful Rotating Cube Demo

February 19, 2025 by Donald Papp 8 Comments

[James Sharman] designed and built his own 8-bit computer from scratch using TTL logic chips, including a VGA adapter, and you can watch it run a glorious rotating cube demo in the video below.

The rotating cube is the product of roughly 3,500 lines of custom assembly code and looks fantastic, running at 30 frames per second with shading effects from multiple light sources. Great results considering the computing power of his system is roughly on par with vintage 8-bit home computers, and the graphics capabilities are limited. [James]’s computer uses a tile map instead of a frame buffer, so getting 3D content rendered was a challenge.

The video is about 20 seconds of demo followed by a detailed technical discussion on how exactly one implements everything required for a 3D cube, from basic math to optimization. If a deep dive into that sort of thing is up your alley, give it a watch!

We’ve featured [James]’ fascinating work on his homebrew computer before. Here’s more detail on his custom VGA adapter, and his best shot at making it (kinda) run DOOM.

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Get Ready For KiCAD 9!

February 17, 2025 by Jenny List 54 Comments

Rev up your browsers, package managers, or whatever other tool you use to avail yourself of new software releases, because the KiCAD team have announced that barring any major bugs being found in the next few hours, tomorrow should see the release of version 9 of the open source EDA suite. Who knows, depending on where you are in the world that could have already happened when you read this.

Skimming through the long list of enhancements brought into this version there’s one thing that strikes us; how this is now a list of upgrades and tweaks to a stable piece of software rather than essential features bringing a rough and ready package towards usability. There was a time when using KiCAD was a frustrating experience of many quirks and interface annoyances, but successive versions have improved it beyond measure. We would pass comment that we wished all open source software was as polished, but the fact is that much of the commercial software in this arena is not as good as this.

So head on over and kick the tires on this new KiCAD release, assuming that it passes those final checks. We look forward to the community’s verdict on it.

How Hard Is It To Write A Calculator App?

February 16, 2025 by Al Williams 40 Comments

How hard can it be to write a simple four-function calculator program? After all, computers are good at math, and making a calculator isn’t exactly blazing a new trail, right? But [Chad Nauseam] will tell you that it is harder than you probably think. His post starts with a screenshot of the iOS calculator app with a mildly complex equation. The app’s answer is wrong. Android’s calculator does better on the same problem.

What follows is a bit of a history lesson and a bit of a math lesson combined. As you might realize, the inherent problem with computers and math isn’t that they aren’t good at it. Floating point numbers have a finite precision and this leads to problems, especially when you do operations that combine large and small numbers together.

Indeed, any floating point representation has a bigger infinity of numbers that it can’t represent than those that it can. But the same is true of a calculator. Think about how many digits you are willing to type in, and how many digits you want out. All you want is for each of them to be correct, and that’s a much smaller set of numbers.

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Why AI Usage May Degrade Human Cognition And Blunt Critical Thinking Skills

February 13, 2025 by Maya Posch 94 Comments

Any statement regarding the potential benefits and/or hazards of AI tends to be automatically very divisive and controversial as the world tries to figure out what the technology means to them, and how to make the most money off it in the process. Either meaning Artificial Inference or Artificial Intelligence depending on who you ask, AI has seen itself used mostly as a way to ‘assist’ people. Whether in the form of a chat client to answer casual questions, or to generate articles, images and code, its proponents claim that it’ll make workers more efficient and remove tedium.

In a recent paper published by researchers at Microsoft and Carnegie Mellon University (CMU) the findings from a survey are however that the effect is mostly negative. The general conclusion is that by forcing people to rely on external tools for basic tasks, they become less capable and prepared of doing such things themselves, should the need arise. A related example is provided by Emanuel Maiberg in his commentary on this study when he notes how simple things like memorizing phone numbers and routes within a city are deemed irrelevant, but what if you end up without a working smartphone?

Does so-called generative AI (GAI) turn workers into monkeys who mindlessly regurgitate whatever falls out of the Magic Machine, or is there true potential for removing tedium and increasing productivity?

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C++ Is 45 Years Old. [Stroustrup] Says You Still Don’t Get It!

February 9, 2025 by Al Williams 117 Comments

We were surprised when we read a post from C++ creator [Bjarne Stroustrup] that reminded us that C++ is 45 years old. His premise is that C++ is robust and flexible and by following some key precepts, you can avoid problems.

We don’t disagree, but C++ is much like its progenitor, C, in that it doesn’t really force you to color inside the lines. We like that, though. But it does mean that people will go off and do things the way they want to do it, for any of a number of good and bad reasons.

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Software In Progress

February 8, 2025 by Elliot Williams 70 Comments

Open source software can be fantastic. I run almost exclusively open software, and have for longer than I care to admit. And although I’m not a serious coder by an stretch, I fill out bug reports when I find them, and poke at edge cases to help the people who do the real work.

For 3D modeling, I’ve been bouncing back and forth between OpenSCAD and FreeCAD. OpenSCAD is basic, extensible, and extremely powerful in the way that a programming language is, and consequently it’s reliably bug-free. But it also isn’t exactly user friendly, unless you’re a user who likes to code, in which case it’s marvelous. FreeCAD is much more of a software tool than a programming language, and is a lot more ambitious than OpenSCAD. FreeCAD is also a program in a different stage of development, and given its very broad scope, it has got a lot of bugs.

I kept running into some really serious bugs in a particular function – thickness for what it’s worth – which is known to be glitchy in the FreeCAD community. Indeed, the last time I kicked the tires on thickness, it was almost entirely useless, and there’s been real progress in the past couple years. It works at least sometimes now, on super-simple geometries, and this promise lead me to find out where it still doesn’t work. So I went through the forums to see what I could do to help, and it struck me that some people, mostly those who come to FreeCAD from commercial programs that were essentially finished a decade ago, have different expectations about the state of the software than I do, and are a lot grumpier.

Open source software is working out its bugs in public. Most open source is software in development. It’s growing, and changing, and you can help it grow or just hang on for the ride. Some open-source userland projects are mature enough that they’re pretty much finished, but the vast majority of open-source projects are coding in public and software in progress.

It seems to me that people who expect software to be done already are frustrated by this, and that when we promote super-star open projects like Inkscape or Blender, which are essentially finished, we are doing a disservice to the vast majority of useful, but still in progress applications out there that can get the job done anyway, but might require some workarounds. It’s exactly these projects that need our help and our bug-hunting, but if you go into them with the “finished” mentality, you’re setting yourself up for frustration.

A Programming Language For Building NES Games

February 8, 2025 by Tom Nardi 27 Comments

Generally speaking, writing your own games for retro consoles starts with C code. You’ll need to feed that through a console-specific tool-chain, and there’s certainly going to be some hoops to jump through, but if everything goes as expected, you should end up with a ROM file that can be run in an emulator or played on real hardware if you’ve got the necessary gadgetry to load it.

But NESFab takes things in a slightly different direction. While the code might look like C, it’s actually a language specifically tailored for developing games on the Nintendo Entertainment System (NES). The documentation claims that this targeted language not only compiles into considerably faster 6502 assembly than plain C on GCC or LLVM, but is designed to work around the strengths (and weaknesses) of the NES hardware.

Looking deeper into the example programs and documentation, NESFab offers quite a few quality of life features that should make developing NES games easier. For one thing, there’s integrated asset loading which automatically converts your image files into something the console can understand. One just needs to drop the image file into the source directory, open it in the code with the file function, and the build system will take care of converting it on the fly as the ROM is built. The nuances of bank switching — the organization of code and assets so they fit onto the physical ROM chips on the NES cartridge — are similarly abstracted away.

The obvious downside of NESFab is that, as with something like GB Studio, you’re going to end up putting effort into learning a programming environment that works for just one system. So before you get started, you really need to decide what your goals are. If you’re a diehard NES fan that has no interest in working on other systems, learning a language and build environment specifically geared to that console might make a certain degree of sense. But if you’d like to see your masterpiece running on more than just one system, working in straight C is still going to be your best bet.