Cheapest (CPU-wise) way to get scanlines

RetroArch Additions Shaders
#1

I am running retroarch on a Pandora’s box which uses an Allwinner A13-based board. That is a single 1GHz core arm CPU.

While emulation runs fine on it - I get 60 fps on most platform and games - whenever I try to use any CRT shader, that drops dramatically… to an unplayable “below 15” .

That also happens with the “crt-pi” shader, that as far as know is one of the least taxing shaders.

I wonder if there is any way to get any scanlines on my system or if I am condemned to see the game that ugly on my screen.

Thanks for any clues!

#2

if it can’t even handle crt-pi, you might be stuck using overlay-based effects.

#3

Thank you for your reply.

I am having an hard time realizing how a shader can be more expensive in terms of CPU cycles that emulating a system.

Is there any overlay that you could please recommend to get a scanline effect? Thank you very much,

#4

Shaders run on the GPU rather than the CPU. Overlays are very cheap because they’re just an image that gets drawn over the top.

Look in effects > scanlines. There are quite a few in there for different resolutions and effects, some of which are fancier than just gray/black lines, if that’s what you’re looking for.

2 Likes
#5

Thank you very much for pointing me in this direction.

1 Like
#6

You can also try lowering the resolution. 720p is enough in my opinion.

1 Like
#7

On my GPD XD +, I use the “scanline-fract.glsl” shader which is located in the Scanlines folder. It gets good results on screen and is not heavy at all.

#8

Thanks, but that’s a quad-core 1.4GHz system. Mine is single-core and its clock speed is 1GHz, thus I am afraid it won’t be enough for that either. But I’ll try ASAP.

#9

Scanlines-sine-abs, it’s in scanlines folder. No preset, you will have to pick it in pass 0, and linear, no care.