Scanlines Shader Opacity

BrockBoyts

Pi Model: 2
RetroPie Version Used: 3.8.1
Emulator: Lr-mame2003
Overlays: rp-video-manager

Hey guys! I am using the amazing rp-video-manger to add arcade bezels and shaders to my games. I love it!

Any chance someone can't point me in the right direction to adjust the opacity of the scanlines within the shader? They make my games just a tad too dark for my taste.

Thanks!

Floob

The video manager tool isnt part of the RetroPie project, so support will be limited.
Are you talking about the bezel effect / shader combo seen here?

If so, the shader is set to crt-pi which is made by davej. For the arcade bezels, it should appear here:
/opt/retropie/emulators/retroarch/shader/arcade-bezel-shader/shaders/crt-pi.glsl

You'll see the scanline weight at the top of that file, see here:
https://retropie.org.uk/forum/topic/2592/video-smoothing-yay-or-nay/26

BrockBoyts

@Floob

Hi! Thank you!

I found the parameters but I don't quite know what each number means in each. Can you explain this to me before I mess around with it? I was having a tough time locating info on these numbers online.

#pragma parameter SCANLINE_WEIGHT "Scanline weight" 6.0 0.0 15.0 0.1
#pragma parameter SCANLINE_GAP_BRIGHTNESS "Scanline gap brightness" 0.12 0.0 1.0 0.01

Thanks!

Floob

Sorry, I'm not sure of the definition of the parameters there, probably one for @davej

Notes from davej posts are:
SCANLINES enables scanlines. You'll almost certainly want to use it with MULTISAMPLE to reduce moire effects.

SCANLINE_WEIGHT defines how wide scanlines are (it is an inverse value so a higher number = thinner lines).
SCANLINE_WEIGHT governs how wide the dark lines are so decreasing it will brighten the image but makes scanlines less even.

SCANLINE_GAP_BRIGHTNESS defines how dark the gaps between the scan lines are. Darker gaps between scan lines make moire effects more likely. Increase this to brighten the image but the scanlines will be less prominent.

Increasing MASK_BRIGHTNESS will make the phosphor mask emulation less obvious. If you're not bothered about phosphor emulation at all you could set MASK_TYPE to 0 which will disable it completely.

Increasing BLOOM_FACTOR will brighten the image at the expense of reducing the already limited bloom effect.

More info:
https://retropie.org.uk/forum/topic/3460/scanlines-shader-opacity/8

BrockBoyts

@davej

Any chance you can help me understand which numbers I should change to lessen the scanlines a little in the crt.pi.glsl?

I feel it darkens my games just a tad bit too much for my taste. Thanks!

davej

@BrockBoyts said in Scanlines Shader Opacity:

@davej

Any chance you can help me understand which numbers I should change to lessen the scanlines a little in the crt.pi.glsl?

The easiest way is to use the retroarch menu. Use the shaders option in the quick menu. There is a bug that stops it working with threaded video so turn that off before making the changes and back on again when you're happy with the result. This method has the advantage that it doesn't change the crt-pi.glsl file.

This post explains how changing each value affects the brightness.

As for the numbers in the #pragma parameter lines, they are really there to define parameters for the retroarch menu. They are, in order: default value, minimum value, maximum value and change amount. If you want to make a change in the crt-pi.glsl file, change the default value.

BrockBoyts

@davej

Thank you. I will play around with the both. How do you pull up the retroarch GUI again?

Floob

@BrockBoyts Start+X