Didn’t think the Rp3 was this weak, but literally every shader I apply causes slow downs. Really would like to have 1) horizontal scan lines and 2) curved edges and rounded corners. There’s this “crt-geom” shader that meets this criteria except one thing…it’s way too slow when applied.
Crt-easymode is the fastest option that offers all of those but I think it’s too slow for RPi3, as well. Crt-pi and fakelottes should be full speed but don’t have rounded corners.
Rather than doing the corners in the shader, which is very computationally expensive for what you get, you could try using an overlay with rounded edges instead.
I had not really looked into overlays. Looked it up based on your suggestion and I am liking what I am seeing on this page:
I will have to try some of these out and see how they perform.
I changed the render resolution on my Pi to 720p for extra power. Shaders for a curved screen won’t look good at this resolution, but I just put on an overlay that covers the edges a bit.