Source
- URL: https://x.com/NOTimothyLottes/status/1688491417109196800
- Author: NOTimothyLottes (@NOTimothyLottes)
- Posted: 2023-08-07 10:04:59
Thread
1/ @NOTimothyLottes
CRT emulation on LCDs can be hard. For example it’s often easy to generate a pattern that causes a LCD hardware bug. NOT joking. Here is an example on the Steam Deck. The pattern in the window affects the scan (Deck scan is rotated) outside the window.
Branches: 2023-08-10-BlurBusters-very-interesting-crosstalk-from-voltage-inversion
2/ @NOTimothyLottes
The actual pattern is this (it’s a 2x1 pixel checker of {G,RB}).
3/ @NOTimothyLottes
The theory: Deck’s 90deg scan results in {(bottom)R, G, B (top)} sub-pixel components. So could alternate {G,RB} only per pixel in a checker pattern to generate a new sub-pixel pattern at a different resolution. In this case trying for 640x400 virtual resolution.
4/ @NOTimothyLottes
For virtual pixel, shift energy into masked virtual phosphor. So 50% brightness red, would be {100%, 0%} for {in, out} of phosphor pixels. Over 50% one starts to increase non-phosphor pixels until some maximum so mask is still visible, but brightness isn’t too compromised.
5/ @NOTimothyLottes
Of course this is done in linear, so it’s energy conserving in theory. But when the panel fails, it breaks down and doesn’t work. I see this problem on a bunch of different devices. My personal AMD laptop has the exact same fail case (but rotated differently).