Atari 2600 (lr-stella) + crt-pi.glslp shader or similar

edmaul69

@alturis flickering isnt an emulator problem. It is an atari 2600 problem. An accurate emulator is going to act exactly like the real system. As far as the crt-pi issue i am not at home to test and speak on.

dudleydes

@alturis From the Atari 2600 Pac-Man wikipedia page:

Pac-Man and ghost characters were implemented using the 2600's two Player objects, with one being used for Pac-Man and the other being used for all four ghosts, with the result that each ghost only appears once out of every four frames, which creates a flickering effect.

Clyde

@dudleydes Bleeding edge tech of its time. :)

ChuckyP

Atari game developers really worked every angle to get games to work around limitations. Some awesome history available if you enjoy reading technical manuals. 😎

Can’t verify your findings on my setup regarding crt-pi. I don’t use curvature myself. But changing the shader doesn’t replicate your problem here.

Alturis

This is my exact cfg if anyone spots anything:

# Settings made here will only override settings in the global retroarch.cfg if placed above the #include line

input_remapping_directory = "/opt/retropie/configs/atari2600/"

video_shader_enable = "true"
video_shader = "~/.config/retroarch/shaders/crt-pi-curvature.glslp" 

input_overlay = /opt/retropie/emulators/retroarch/overlays/arcade-bezels/tv.cfg
input_overlay_enable = true
input_overlay_opacity = 1.000000
input_overlay_scale = 1.000000

#include "/opt/retropie/configs/all/retroarch.cfg"

Alturis

It actually only seems to affect certain games.

The ones I have confirmed:

The bullets in Space Invaders
Various objects in Frogger
Yar's Revenge - bullets and the band and lots of stuff
Dig Dug

Clyde

@alturis I can confirm that. The crt-pi-curvature shader makes the normally flickering objects "blink" in and out much more slowly, making them invisible for long periods.

This effect doesn't occur with @ghogan42's zfast_crt_curve shader.

Alturis

@clyde Excellent thank you! Will give that a try.

Alturis

@clyde said in Atari 2600 (lr-stella) + crt-pi.glslp shader or similar:

This effect doesn't occur with @ghogan42's zfast_crt_curve shader.

Hmm... That doesn't seem to be what I am seeing in my tests. I tried both zfast_crt_curve and zfast_crt_standard and both demonstrate the same issues with frogger elements disappearing.

Edit: Wait actually something is wrong in the way that the shader is being selected in my tests. After opening the in game menus to see what shader I had active it was still using the crt-pi version. Then manually switching to zfast fixed it yes. My bad. I will figure out what the deal is with my options setup and switch to those across the board. Thank you!

Alturis

Hmm.... this is totally confusing me. I now cannot figure out why it is launching and loading the wrong shader.

My dev/shm/runcommand.log shows that it is loading the .cfg that it should be

/opt/retropie/configs/atari2600/retroarch.cfg

Executing: /opt/retropie/emulators/retroarch/bin/retroarch -L /opt/retropie/libretrocores/lr-stella/stella_libretro.so --config /opt/retropie/configs/atari2600/retroarch.cfg "/home/pi/RetroPie/roms/atari2600/Adventure (1980) (Atari).bin" --appendconfig /dev/shm/retroarch.cfg

Which specifies it should use the zfast_crt shader:

video_shader = "~/.config/retroarch/shaders/zfast_crt_curve.glslp"

Yet in game it is still actively using crt-pi-curvature when I check in the menus. Cannot see how that could be possible.

Clyde

@alturis Have you by any chance saved a game override in addition to the core config? See Config Hierarchy.

Alturis

@clyde said in Atari 2600 (lr-stella) + crt-pi.glslp shader or similar:

@alturis Have you by any chance saved a game override in addition to the core config? See Config Hierarchy.

Nope. My atari2600 roms folder has no .cfg files in it at all. I have even installed locate, updated the db, and searched for al cases of atari2600 and there are no other .cfg files with that name in it other than the one I expect.

Alturis

Totally baffled by this still. I even ran a grep of the entirety of /opt /dev /home /etc for anything containing 'crt-pi-curvature' and its only finding it in the places I already know about or unrelating things like the shader glslp files themselves.

I even tried using the in-game menu to change to zfast then saved that as the core default and still each time I re-open an atari2600 game it is back to crt-pi-curvature.glsl in shader pass 0

Stumped. ;(

Alturis

@alturis I think i figured it out. In my grep results I overlooked it because it was hidden as a glslp entry within the shaders/presets/Stella folder

So basically I had an entry in that folder called <rom_name_I_was_testing>.glslp that was still referring to the crt-pi-curvature.hlsl and it was using that instead of the core settings.

dankcushions

@alturis said in Atari 2600 (lr-stella) + crt-pi.glslp shader or similar:

@clyde said in Atari 2600 (lr-stella) + crt-pi.glslp shader or similar:

@alturis Have you by any chance saved a game override in addition to the core config? See Config Hierarchy.

Nope. My atari2600 roms folder has no .cfg files in it at all. I have even installed locate, updated the db, and searched for al cases of atari2600 and there are no other .cfg files with that name in it other than the one I expect.

game overrides are not stored in rom folder. they would be in (from memory) /opt/retropie/configs/all/retroarch/config/ (somewhere in here)