slang-shaders/vhs/shaders/vhs.slang

#version 450

// VHS shader
// by hunterk
// adapted from ompuco's more AVdistortion shadertoy:
// https://www.shadertoy.com/view/XlsczN

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

#pragma parameter wiggle "Wiggle" 0.0 0.0 10.0 1.0
#pragma parameter smear "Chroma Smear" 0.5 0.0 1.0 0.05

#define wiggle params.wiggle
#define smear params.smear
#define FrameCount params.FrameCount

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

#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;
   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;

#define iTime mod(float(FrameCount), 7.0)
#define iChannel0 Source

//YIQ/RGB shit
vec3 rgb2yiq(vec3 c){   
	return vec3(
		(0.2989*c.x + 0.5959*c.y + 0.2115*c.z),
		(0.5870*c.x - 0.2744*c.y - 0.5229*c.z),
		(0.1140*c.x - 0.3216*c.y + 0.3114*c.z)
	);
}

vec3 yiq2rgb(vec3 c){				
	return vec3(
		(1.0*c.x	+ 1.0*c.y	+ 1.0*c.z),
		(0.956*c.x	- 0.2720*c.y	- 1.1060*c.z),
		(0.6210*c.x	- 0.6474*c.y	+ 1.7046*c.z)
	);
}
        
vec2 Circle(float Start, float Points, float Point) 
{
	float Rad = (3.141592 * 2.0 * (1.0 / Points)) * (Point + Start);
	//return vec2(sin(Rad), cos(Rad));
		return vec2(-(.3+Rad), cos(Rad));

}

vec3 Blur(vec2 uv, float d){
	float t = (sin(iTime*5.0+uv.y*5.0))/10.0;
    float b = 1.0;
    t=0.0;
    vec2 PixelOffset=vec2(d+.0005*t,0);
    
    float Start = 2.0 / 14.0;
    vec2 Scale = 0.66 * 4.0 * 2.0 * PixelOffset.xy;
    
    vec3 N0 = texture(iChannel0, uv + Circle(Start, 14.0, 0.0) * Scale).rgb;
    vec3 N1 = texture(iChannel0, uv + Circle(Start, 14.0, 1.0) * Scale).rgb;
    vec3 N2 = texture(iChannel0, uv + Circle(Start, 14.0, 2.0) * Scale).rgb;
    vec3 N3 = texture(iChannel0, uv + Circle(Start, 14.0, 3.0) * Scale).rgb;
    vec3 N4 = texture(iChannel0, uv + Circle(Start, 14.0, 4.0) * Scale).rgb;
    vec3 N5 = texture(iChannel0, uv + Circle(Start, 14.0, 5.0) * Scale).rgb;
    vec3 N6 = texture(iChannel0, uv + Circle(Start, 14.0, 6.0) * Scale).rgb;
    vec3 N7 = texture(iChannel0, uv + Circle(Start, 14.0, 7.0) * Scale).rgb;
    vec3 N8 = texture(iChannel0, uv + Circle(Start, 14.0, 8.0) * Scale).rgb;
    vec3 N9 = texture(iChannel0, uv + Circle(Start, 14.0, 9.0) * Scale).rgb;
    vec3 N10 = texture(iChannel0, uv + Circle(Start, 14.0, 10.0) * Scale).rgb;
    vec3 N11 = texture(iChannel0, uv + Circle(Start, 14.0, 11.0) * Scale).rgb;
    vec3 N12 = texture(iChannel0, uv + Circle(Start, 14.0, 12.0) * Scale).rgb;
    vec3 N13 = texture(iChannel0, uv + Circle(Start, 14.0, 13.0) * Scale).rgb;
    vec3 N14 = texture(iChannel0, uv).rgb;
    
	vec4 clr = texture(iChannel0, uv);
    float W = 1.0 / 15.0;
    
    clr.rgb= 
		(N0 * W) +
		(N1 * W) +
		(N2 * W) +
		(N3 * W) +
		(N4 * W) +
		(N5 * W) +
		(N6 * W) +
		(N7 * W) +
		(N8 * W) +
		(N9 * W) +
		(N10 * W) +
		(N11 * W) +
		(N12 * W) +
		(N13 * W) +
		(N14 * W);
    return  vec3(clr.xyz)*b;
}

float onOff(float a, float b, float c, float framecount)
{
	return step(c, sin((framecount * 0.001) + a*cos((framecount * 0.001)*b)));
}

vec2 jumpy(vec2 uv, float framecount)
{
	vec2 look = uv;
	float window = 1./(1.+80.*(look.y-mod(framecount/4.,1.))*(look.y-mod(framecount/4.,1.)));
	look.x += 0.05 * sin(look.y*10. + framecount)/20.*onOff(4.,4.,.3, framecount)*(0.5+cos(framecount*20.))*window;
	float vShift = (0.1*wiggle) * 0.4*onOff(2.,3.,.9, framecount)*(sin(framecount)*sin(framecount*20.) + 
										 (0.5 + 0.1*sin(framecount*200.)*cos(framecount)));
	look.y = mod(look.y - 0.01 * vShift, 1.);
	return look;
}

void main()
{
	float d = .1-round(mod(iTime/3.0,1.0))*.1;
	vec2 uv = jumpy(vTexCoord.xy, iTime);
	vec2 uv2 = uv;

	float s = 0.0001 * -d + 0.0001 * wiggle * sin(iTime);
   
	float e = min(.30,pow(max(0.0,cos(uv.y*4.0+.3)-.75)*(s+0.5)*1.0,3.0))*25.0;
	float r = (iTime*(2.0*s));
	uv.x += abs(r*pow(min(.003,(-uv.y+(.01*mod(iTime, 17.0))))*3.0,2.0));
    
	d = .051+abs(sin(s/4.0));
	float c = max(0.0001,.002*d) * smear;
	vec2 uvo = uv;
	vec4 final;
	final.xyz =Blur(uv,c+c*(uv.x));
	float y = rgb2yiq(final.xyz).r;
    
	uv.x += .01*d;
	c *= 6.0;
	final.xyz =Blur(uv,c);
	float i = rgb2yiq(final.xyz).g;
    
	uv.x += .005*d;
    
	c *= 2.50;
	final.xyz =Blur(uv,c);
	float q = rgb2yiq(final.xyz).b;
	final = vec4(yiq2rgb(vec3(y,i,q))-pow(s+e*2.0,3.0), 1.0);
	
	FragColor = final;
}