Fudoh, I haven't used to the raspberry pie version of retroarch but but I do have quite a bit of experience with the x86 and console versions.
(are you connecting this to your main gaming TV?)
does your version have the "tvout+interlacing" shader? (in my opinion it's the best way to create that BVM/PVM look and it also has an alternating scanline feature like the OSSC) I made a few post about it in the HLSL CRT SCANLINE EMULATION thread (with some pictures comparing it to actual CRTs)
http://shmups.system11.org/viewtopic.php?f=6&t=45026&p=1196201&hilit=+shader#p1196201http://shmups.system11.org/viewtopic.php?f=6&t=45026&p=1198588&hilit=+shader#p1198588once again I'm not sure how the pie version handles it but I've noticed with retroarch (in general), that I have to turn on and off integer scaling every time you load a new game to get the settings just perfect (as some games have different resolutions even on the same system). (so whenever I load a game, I make sure to adjust the integer settings)
whenever I use retroarch to adjust the internal options of shaders, I always go to the shader menu and adjust the "Preview Shader Parameters" setting on a game by game basis. (but this is only because I mess around with dithering options, most people will find a specific combination they like and just dial it in by saving the shader preset).
it has an option you can adjust to approximate the TVL or lines of resolution to match the tube your attempting to emulate (for instance most of the time I use 800 to emulate a Sony PVM 20L5 which has 800TVL) (although most people usually set it to 1024 TVL for the most razor-sharp image possible)
if your integers are correct, it should give you the proper scanline pattern for whatever game you're using, but the default scanlines are similar to the OSSC's 720P mode (little thin for my tastes) enabling the mode "Top Field First Enable" creates the thicker, more natural looking scanlines (on older versions of the shader I believe this was enabled by default)
(here's a picture of the shader tvout+interlacing being used on a Sony FW900 at sextuple PCE resolution)