Using a PC for CRT shaders with original hardware

[SGGG2]

Shaderglass 1.0 released

New in v1.0 (21 Feb 2025):

refresh of RetroArch shader library
back-end extensions to support more complex shaders (MegaBezel)
improved fullscreen with letterboxing and aspect ratio preservation
quick access to Recent Profiles from menu
FPS display in title bar
selection of best shaders in Browser window
bug fixes

https://mausimus.itch.io/shaderglass
https://github.com/mausimus/ShaderGlass

[syboxez]

WindowCast can also be used if you want to use RetroArch directly, or if you are a Linux user. RetroArch also supports V4L2, but in my experience, that's broken as of now.

https://gitlab.com/johnsirett-public/windowcast-2

[SGGG2]

Shaderglass 1.2.0 released. Capture cards are supported directly (as opposed to using desktop capture). This should provide more accurate effects alignment. In theory, anyway.

https://mausimus.itch.io/shaderglass

[e8root]

Neat idea in itself but I would imagine lag is quite bad and capture cards aren't known for being able to perfectly capture pixel perfect images making too many assumptions about input resolution and also refresh rate is probably an issue so lag isn't very stable. Here you also add additional lag from ShaderGlass.

O your screenshots you can see 240p image was treated as 480i and you only excessively blurred the image with CRT shader. Not my cup of tea...

There is a way to get below 1 frame of lag with proper image quality and no shuttering to challenge likes of RetroTink4K but it would require dedicated solution. Likely also hardware solution or at the very least different drivers.
Topic is very interesting and I guess that given rising popularity of retro gaming someone will pick it up eventually and give us something that can challenge likes of RetroTink4K.

[SGGG2]

I've already demonstrated 1 frame of capture lag on the PC side, (if you use an OSSC/Pro in line double mode there's zero effective lag coming from the scaler) and modern capture cards are for sure more than good enough for images that are getting processed ANYWAY...

I've discovered that making stats visible on ReShade causes a huge spike in processing time, around 30%, so there's a ton of headroom using OSSC/HD60X/OBS/ReShade with a decent graphics card. Processing times for 1440 and 1080p are way lower.

A zero lag digitizer would be awesome, but the real bottleneck here is the lack of dedicated software and console templates.

[orange808]

The drivers and scheduling are the stubborn bottlenecks on a PC. A GPU is more than just a frame buffer; it's a computer in itself--ableit a modular one, but a computer (nevertheless). There's a lot of overhead that comes with that.

We'll see if any new DMA schemes for ML accidentally throw us a bone. I'm not optimistic.