I experimented with building a faux VFD effect on modern screens. Just a quick prototype without a lot of polish. Certainly not nearly as much as some other projects out there putting a retro look on modern screens. One of those I’ve been impressed with is cool-retro-term. (Mentioned as almost an aside in this Hackaday article about a mini PDP-11 project.) I installed it on my Ubuntu machine and was very amused to see a window pop up looking like an old school amber CRT computer monitor.

The amber color looks perfect, and the text received a coordinate transform to make the text area look like a curved surface. Not visible in a screenshot are bits of randomness added to the coordinate transform emulating the fact CRT pixels aren’t as precisely located as LCD pixels. There is also a slight visual flicker effect simulating CRT vertical refresh.

The detail I found most impressive is the fact effects aren’t limited to the “glass” area: there is even a slight reflection of text on the “bezel” area!

So how was all this done? Poking around the GitHub repository I think this was written using Qt native UI framework. Qt was something I had ambition to learn, but I’ve put more time into learning web development because of all the free online resources out there. I see a lot of files with the *.qml extension, indicating this is a newer way to create Qt interfaces: QML markup versus API calls from code. Looking around for something that looks like the core of emulating imperfect CRTs, the most promising candidate for a starting point is the file ShaderTerminal.qml. I see mentions of CRT visual attributes like static noise, curvature, flickering, and more.

It should be possible to make an online browser version of this effect. If the vertex shaders in cool-retro-term are too complex for WebGL, it should be possible to port them to WebGPU. Turning that theory into practice would require me to actually get proficient with WebGPU, and learn enough Qt to understand all the nuts and bolts of how cool-retro-term works so I can translate them. Given my to-do list of project ideas, this is unlikely to rise to the top unless some other motivation surfaces.