CRT Scanline Effect for Dolphin Emulator

mad-scanlines-crt.glsl

void main()
{
	float currentMillis = GetTime() / float(1000.0);
	float2 coords = GetCoordinates();
	float lineCount = GetWindowResolution().y / 2.0;

    // scanlines
    int lineIndex = int( ( coords.y + currentMillis * 0.5 ) * lineCount );
#ifdef API_OPENGL
    float lineIntensity = mod(float(lineIndex), 2);
#elif API_VULKAN
    float lineIntensity = mod(float(lineIndex), 2);
#else
	float lineIntensity = float(lineIndex) % 2.0;
#endif
    // color shift
    float off = lineIntensity * 0.0005;
    float4 shift = float4( off, 0, 0, 0 );
    
    // shift R and G channels to simulate NTSC color bleed
    float4 colorShift = float4( 0.001, 0, 0, 0 );
    float r = (Sample() + colorShift + shift).x;
    float g = (Sample() - colorShift + shift).y;
    float b = Sample().z;
    
    float4 c = float4( r, g * 0.99, b, 1.0 ) * clamp( lineIntensity, 0.85, 1.0 );
    
    float rollbar = sin( ( coords.y + currentMillis ) * 4.0 );
    
	SetOutput(c + (rollbar * 0.02));
}

Hello

I tried the filter with super Mario galaxy.

In the level where you groundpound things for big larva to connect the apples, and in the end fight a big mole as the boss, I noticed that the filter has a hard time keeping up when the camera is moving fast, creating horizontal lines and darkening of the image that scrolls past the whole screen - similar to when you would film a CRT with a camera back in the day.

Felt like commenting since I really like the filter you've created and would love to see it improved to solve the issues with challenging camera movement.

Keep up the good work!
Cheers

I found a link to this filter on Dolphin forums. I'll try it later... Wanted dev to know. I'll try with Skyward Sword and other Zelda titles. I mostly played those on CRT. I even had a CRT with component cables input and 480p.

EDIT: I tried with Skyward Sword and it's quite good, although I think it's too flickery 😅

How to download this?

How to download this?

same question lol

No need to download. simply go to your Dolphin\Sys\Shaders folder, create a new file called mad-scanlines-crt.glsl and paste the contents of this gist. Enjoy :)

I made another one if you don't like the flickering
https://gist.github.com/mariodivece/dab278f82ef3725b06001adec28ef92b

Thanks! :D

How to mix this with this one for RE4?
https://forums.dolphin-emu.org/Thread-zoom-widescreen-shader-for-letterboxed-gc-games-like-resident-evil-4

I made another one if you don't like the flickering https://gist.github.com/mariodivece/dab278f82ef3725b06001adec28ef92b

I like the look of this one better than the other one, where I feel the lines are too thick. Is there a way to turn the flickering off on this one?

Here I leave you my own version, see if you like it:

https://www.mediafire.com/file/164jvb9plhi0sjq/scanlines.zip/file

@mariodivece
I've fixed a compilation error with the modulo operator. Line 14 under // scanlines uses '%' for modulo instead of 'mod()'. It has been changed to match the above lines for OpenGL and Vulkan APIs.

Please review my fork here.