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@mariodivece
Last active September 14, 2026 05:38
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CRT Scanline Effect for Dolphin Emulator
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));
}
@Alkimical

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@Shalashaskka

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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?

@Mortendrak

Mortendrak commented Sep 26, 2024

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

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

@ashley-wilkinson

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@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.

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