Stuttering Lakka due to Shader + Overlay


@hunterk @gouchi Ok, I’ve been meaning to post this for a long time, but I wanted to wait and test lots of nightlies and research to make sure I don’t waste anyone’s time.

I use a Raspberry Pi 3B and have a terrible problem with Lakka: I can’t use a shader combined with an overlay bezel. At first I thought this problem was caused because I was using a big 1080p image for a bezel with lots of colors and semi transparent pixels, but even if I just use a simple white frame, it will cause stuttering if I add a shader. (The bezel being a tiny file with small resolution as well and only literally 1 color on the image) Here’s an example of what happens:

This is FCEUmm with the sharp-bilinear.glsl shader, which is in my opinion the simplest / best shader that avoids uneven pixels when using aspect ratios like 4:3 on HD. (or any other size for that matter)

I find this to be a really annoying and unfair problem because this shader is essential, and using bezels is one of the coolest things ever. Plus, these 2 things used to work perfectly fine in a much older version of Lakka I have. However, I do not want to go back to that because Lakka has gotten a LOT better, but this bezel problem has actually existed since around January 2017 nightly builds, and I always assumed it would get fixed at some point.

Notes: I dont use Threaded Video, but when I enable it, the problem is not fixed. Leaving only 1 of the 2 (bezel or shader), it will work perfectly fine as long as they arent combined. I am able to use a shader and bezel when using the Raspberry Pi on a CRT, possibly due to the fact that the resolution is much lower there than a 720p or 1080p monitor, but I have a feeling it should still work just fine on these too. Last thing I tried was TGA instead of PNG for the bezel. No difference there either!


Does it happen if you set your resolution to 1280x720 instead of 1920x1080?

I know that’s not a real solution, just trying to pin down the bottleneck.


Just tested it on the 2018-11-11 Nightly. Everything is really smooth with “hdmi_mode=4” (720p 60 Hz) mode! Although I am not sure about a perfect constant performance. In some games, I notice like 1 frame being dropped every once in a while (which makes the sound crackle a bit), like FF6’s intro on SNES9x 2005 Plus or 2010, but that might be just the normal thing to happen with that core.

Also, I just noticed something. I think in the old build that doesnt have the problem, there were no touch screen features with the overlay! (At least I dont see them in the menu)

Side question: I also just noticed that roms seem to load practically instantly in the old build, while in every newer build, you have to wait a few seconds with the Lakka berry icon on screen before it loads, why is that?