Which shader/video filter setting for Atari 7800?

TimZett

Any recommendations?
I'd like to extend my Atari 7800 retroarch.cfg and apply some video filter/shader settings which considerably, not to say quite extremely blur the image on games.
On-default it's so blocky.

I tried these but i see no any change:
https://retropie.org.uk/forum/topic/20024/slang-shaders-configurations-for-each-system/2

Any ideas/recommendations?

TimZett

Hmm - meanwhile I came across this folder here:

/retropie/configs/all/retroarch/shaders

Is there a way to use these, respectively can I tell the Atari 7800 emulator somhow to use them?

EDIT:
This is how my retroarch.cfg for the Atari 7800 looks right now:

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

input_remapping_directory = "/opt/retropie/configs/atari7800/"

audio_volume = "-10.000000"
Video_smooth = "true"

video_shader_enable = "true"
video_shader = "~/.config/retroarch/shaders/color/palm-color.glslp"

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

I chose an (think so) extra flashy shader, however I can see no any difference.

TimZett

OK guys I got it to work and I'd like to share it with you.
No idea which of the lines are actually mandatory and which not, but anyway it works, e.g. with this CRT filter:

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

input_remapping_directory = "/opt/retropie/configs/atari7800/"

audio_volume = "-10.000000"
Video_smooth = "true"

auto_shaders_enable = "true"
input_shader_next = "m"
input_shader_prev = "n"

video_shader_dir = "~/.config/retroarch/shaders"
video_filter_dir = "default"
video_shader_enable = "true"
video_shader = "~/.config/retroarch/shaders/crt-pi-vertical.glsl"

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

mitu

@TimZett Thank you for sharing the solution. Most likely, the lines needed are

auto_shaders_enable = "true"
video_shader = "~/.config/retroarch/shaders/crt-pi-vertical.glsl"

This can be also be done directly from the RGUI, by saving the shader preset for the core, as described near the end of the doc page.

TimZett

@mitu There must be something missing at yours - I just tried it and the filter isn't applied any longer.
I will play around a bit and let you know later.

By the way, do you know how to apply more than one filter at a time (cascading)?

EDIT:
Got it. This is all we need:

video_shader_enable = "true"
video_shader = "~/.config/retroarch/shaders/[Shader Filename]"

mitu

@TimZett RetroArch distributes Shader presets (.glslp) files which combine multiple shader passes with the parameters accepted by the shaders and can be loaded from the RGUI and then tweaked.
Here's an example of such a preset (crt/gtu-famicon.glslp):

shaders = 5

shader0 = shaders/gtu-famicom/DAC_combined.glsl
scale_type_x0 = source
scale_x0 = 8.0
scale_type_y0 = source
scale_y0 = 1.0
filter_linear0 = false
frame_count_mod0 = 2
float_framebuffer0 = true

shader1 = shaders/gtu-famicom/lowPass.glsl
scale_type_1 = source
scale_1 = 1.0
filter_linear1 = false
frame_count_mod1 = 32
float_framebuffer1 = true

shader2 = shaders/gtu-famicom/combFilter.glsl
scale_type_2 = source
scale_2 = 1.0
filter_linear2 = false
frame_count_mod2 = 2
float_framebuffer2 = true

shader3 = shaders/gtu-famicom/scaleX.glsl
scale_type_x3 = viewport
scale_x3 = 1.0
scale_type_y3 = source
scale_y3 = 1.0
float_framebuffer3 = true
filter_linear3 = false

shader4 = shaders/gtu-famicom/scaleY.glsl
scale_type_x4 = source
scale_x4 = 1.0
scale_type_y4 = viewport
scale_y4 = 1.0
filter_linear4 = false
float_framebuffer4 = true

textures = nestable
nestable = shaders/gtu-famicom/NesTable.png
nestable_linear = false
nestable_mipmap = false
nestable_wrap_mode = clamp_to_border

You can create your own presets - look in the shaders folder - or just add the shaders individually to the .cfg file with the same syntax as above.

TimZett

Thanks mitu.

Now for me the question is whether there is an overview available, about what each shader preset (.glsl) does and in case of a .glslp, what the individual (cascaded) shaders do.

The preset file names, especially those of the .glslp ones, IMO are not really self-explaining in most cases.

EDIT:
I found something:
http://emulation.gametechwiki.com/index.php/Shaders_and_Filters
If you guys know something "better" or more official please share it

Lyle_JP

the crt vertical shader is especially for arcade games with a vertically oriented monitor. If you like the way it makes the Atari 7800 games, then go ahead and keep it, but you might just want to try the vanilla crt-pi shader instead.

mitu

@TimZett I think @dankcushions posted a link (maybe in another topic) to the Shader docs in Retropie's documentation - https://retropie.org.uk/docs/Shaders-and-Smoothing/.