slang-shaders/scanlines/shaders/scanline.slang

#version 450

layout(push_constant) uniform Push
{
	vec4 SourceSize;
	vec4 OriginalSize;
	vec4 OutputSize;
	uint FrameCount;
	float SCANLINE_SINE_COMP_A;
	float SCANLINE_SINE_COMP_B;
} params;

#pragma parameter SCANLINE_SINE_COMP_A "Scanline Sine Comp A" 0.0 0.0 0.10 0.01
#pragma parameter SCANLINE_SINE_COMP_B "Scanline Sine Comp B" 0.15 0.0 1.0 0.05

#define SCANLINE_SINE_COMP_A params.SCANLINE_SINE_COMP_A
#define SCANLINE_SINE_COMP_B params.SCANLINE_SINE_COMP_B

layout(std140, set = 0, binding = 0) uniform UBO
{
	mat4 MVP;
} global;

#define pi 3.141592654

#pragma stage vertex
layout(location = 0) in vec4 Position;
layout(location = 1) in vec2 TexCoord;
layout(location = 0) out vec2 vTexCoord;
layout(location = 1) out vec2 omega;

void main()
{
   gl_Position = global.MVP * Position;
   vTexCoord = TexCoord*1.0001;
   omega = vec2(pi * params.OutputSize.x, 1.999 * pi * params.SourceSize.y);
}

#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 1) in vec2 omega;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;

void main()
{
   vec2 sine_comp = vec2(SCANLINE_SINE_COMP_A, SCANLINE_SINE_COMP_B);
   vec3 res = texture(Source, vTexCoord).xyz;
   vec3 scanline = res * ((1.0-SCANLINE_SINE_COMP_B*0.5) + dot(sine_comp * sin(vTexCoord * omega), vec2(1.0, 1.0)));
   FragColor = vec4(scanline, 1.0);
}