slang-shaders/crt/shaders/gtu-famicom/scaleY.slang

#version 450

layout(push_constant) uniform Push
{
	vec4 SourceSize;
	vec4 OriginalSize;
	vec4 OutputSize;
	uint FrameCount;
	float noScanlines;
	float tvVerticalResolution;
	float blackLevel;
	float contrast;
	float gamma;
	float cropOverscan_y;
} params;

#pragma parameter noScanlines "No Scanlines" 0.0 0.0 1.0 1.0
#pragma parameter tvVerticalResolution "TV Vert. Res" 250.0 20.0 1000.0 10.0
#pragma parameter blackLevel "Black Level" 0.07 -0.30 0.30 0.01
#pragma parameter contrast "Contrast" 1.0 0.0 2.0 0.1
#pragma parameter gamma "Gamma" 1.0 0.5 1.5 0.01
#pragma parameter cropOverscan_y "Crop Overscan Y" 0.0 0.0 1.0 1.0

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

////////////////////////////////////////////////////////
//	GTU-famicom version 0.50
//	Author: aliaspider - aliaspider@gmail.com
//	License: GPLv3
////////////////////////////////////////////////////////

//#include "config.h"

#define pi			3.14159265358
#define normalGauss(x) ((exp(-(x)*(x)*0.5))/sqrt(2.0*pi))

#define Y(j) (offset.y-(j))
#define a(x) abs(x)
#define d(x,b) (pi*b*min(a(x)+0.5,1.0/b))
#define e(x,b) (pi*b*min(max(a(x)-0.5,-1.0/b),1.0/b))
#define STU(x,b) ((d(x,b)+sin(d(x,b))-e(x,b)-sin(e(x,b)))/(2.0*pi))

#define SOURCE(j) vec2(vTexCoord.x,vTexCoord.y - Y(j) * params.SourceSize.w)
#define C(j) (texture(Source, SOURCE(j)).xyz)

#define VAL(j) (C(j)*STU(Y(j),(params.tvVerticalResolution * params.SourceSize.w)))
#define VAL_scanlines(j) (scanlines(Y(j),C(j)))

float normalGaussIntegral(float x)
{
	float a1 = 0.4361836;
	float a2 = -0.1201676;
	float a3 = 0.9372980;
	float p = 0.3326700;
	float t = 1.0 / (1.0 + p*abs(x));
	return (0.5-normalGauss(x) * (t*(a1 + t*(a2 + a3*t))))*sign(x);
}

vec3 scanlines( float x , vec3 c){
	float temp=sqrt(2*pi)*(params.tvVerticalResolution * params.SourceSize.w);

	float rrr=0.5 * (params.SourceSize.y * params.OutputSize.w);
	float x1=(x+rrr)*temp;
	float x2=(x-rrr)*temp;
	c.r=(c.r*(normalGaussIntegral(x1)-normalGaussIntegral(x2)));
	c.g=(c.g*(normalGaussIntegral(x1)-normalGaussIntegral(x2)));
	c.b=(c.b*(normalGaussIntegral(x1)-normalGaussIntegral(x2)));
	c*=(params.OutputSize.y * params.SourceSize.w);
	return c;
}

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

void main()
{
   gl_Position = global.MVP * Position;
   if (params.cropOverscan_y > 0.0)
	gl_Position.y /= (224.0 / 240.0);
   vTexCoord = TexCoord;
}

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

void main()
{
	vec2 offset = fract((vTexCoord.xy * params.SourceSize.xy) - 0.5);
	vec3 tempColor = vec3(0.0);
	
	float range = ceil(0.5 + params.SourceSize.y / params.tvVerticalResolution);
	range = min(range, 255.0);
	
	float i;
//	for (i=-range;i<range+2.0;i++){

   if (params.noScanlines > 0.0)
      for (i=1.0-range;i<range+1.0;i++)
         tempColor+=VAL(i);
   else
      for (i=1.0-range;i<range+1.0;i++)
         tempColor+=VAL_scanlines(i);
		 
	tempColor -= vec3(params.blackLevel);
	tempColor *= (params.contrast / vec3(1.0 - params.blackLevel));
	tempColor = pow(tempColor, vec3(params.gamma));
	FragColor = vec4(tempColor, 1.0);
}