I made a nice setup for you with glow support below. The name of the shader must be considered though in order to work with the preset.

It’s best added as first passes, so it won’t break any other effects.

Yes, it’s included in this shader also. Otherwise it wouldn’t look properly for me any more.

crt-guest-sm-glow.glsl (goes into crt/shaders/guest ):

```
/*
CRT - Guest - SM (Scanline Mask) Shader
Copyright (C) 2019 guest(r) - [email protected]
Big thanks to Nesguy from the Libretro forums for the masks and other ideas.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* README - MASKS GUIDE
To obtain the best results with masks 0, 1, 3, 4:
must leave “mask size” at 1 and the display must be set to its native resolution to result in evenly spaced “active” LCD subpixels.
Mask 0: Uses a magenta and green pattern for even spacing of the LCD subpixels.
Mask 1: Intended for displays that have RBG subpixels (as opposed to the more common RGB).
Uses a yellow/blue pattern for even spacing of the LCD subpixels.
Mask 2: Common red/green/blue pattern.
Mask 3: This is useful for 4K displays, where masks 0 and 1 can look too fine.
Uses a red/yellow/cyan/blue pattern to result in even spacing of the LCD subpixels.
Mask 4: Intended for displays that have the less common RBG subpixel pattern.
This is useful for 4K displays, where masks 0 and 1 can look too fine.
Uses a red/magenta/cyan/green pattern for even spacing of the LCD subpixels.
*/
// Parameter lines go here:
#pragma parameter smart "Smart Y Integer Scaling" 0.0 0.0 1.0 1.0
#pragma parameter brightboost "Bright boost" 1.15 0.5 2.0 0.05
#pragma parameter scanline "Scanline adjust" 8.0 1.0 12.0 1.0
#pragma parameter beam_min "Scanline dark" 1.35 0.5 2.0 0.05
#pragma parameter beam_max "Scanline bright" 1.05 0.5 2.0 0.05
#pragma parameter s_gamma "Scanline gamma" 2.4 1.5 3.0 0.05
#pragma parameter h_sharp "Horizontal sharpness" 2.0 1.0 5.0 0.05
#pragma parameter mask "CRT Mask (3&4 are 4k masks)" 0.0 0.0 4.0 1.0
#pragma parameter maskstr "Raw CRT Mask Strength" 0.15 0.0 1.0 0.05
#pragma parameter masksize "CRT Mask Size" 1.0 1.0 2.0 1.0
#pragma parameter glow "Glow Strength" 0.05 0.0 0.5 0.01
#pragma parameter gamma_out "Gamma Out" 2.40 1.0 3.0 0.05
#if defined(VERTEX)
#if __VERSION__ >= 130
#define COMPAT_VARYING out
#define COMPAT_ATTRIBUTE in
#define COMPAT_TEXTURE texture
#else
#define COMPAT_VARYING varying
#define COMPAT_ATTRIBUTE attribute
#define COMPAT_TEXTURE texture2D
#endif
#ifdef GL_ES
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif
COMPAT_ATTRIBUTE vec4 VertexCoord;
COMPAT_ATTRIBUTE vec4 COLOR;
COMPAT_ATTRIBUTE vec4 TexCoord;
COMPAT_VARYING vec4 COL0;
COMPAT_VARYING vec4 TEX0;
vec4 _oPosition1;
uniform mat4 MVPMatrix;
uniform COMPAT_PRECISION int FrameDirection;
uniform COMPAT_PRECISION int FrameCount;
uniform COMPAT_PRECISION vec2 OutputSize;
uniform COMPAT_PRECISION vec2 TextureSize;
uniform COMPAT_PRECISION vec2 InputSize;
void main()
{
gl_Position = MVPMatrix * VertexCoord;
COL0 = COLOR;
TEX0.xy = TexCoord.xy * 1.00001;
}
#elif defined(FRAGMENT)
#if __VERSION__ >= 130
#define COMPAT_VARYING in
#define COMPAT_TEXTURE texture
out vec4 FragColor;
#else
#define COMPAT_VARYING varying
#define FragColor gl_FragColor
#define COMPAT_TEXTURE texture2D
#endif
#ifdef GL_ES
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif
uniform COMPAT_PRECISION int FrameDirection;
uniform COMPAT_PRECISION int FrameCount;
uniform COMPAT_PRECISION vec2 OutputSize;
uniform COMPAT_PRECISION vec2 TextureSize;
uniform COMPAT_PRECISION vec2 InputSize;
uniform sampler2D Texture;
uniform sampler2D PassPrev4Texture;
COMPAT_VARYING vec4 TEX0;
// compatibility #defines
#define Source Texture
#define vTexCoord TEX0.xy
#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
#define OutputSize vec4(OutputSize, 1.0 / OutputSize)
#ifdef PARAMETER_UNIFORM
// All parameter floats need to have COMPAT_PRECISION in front of them
uniform COMPAT_PRECISION float smart;
uniform COMPAT_PRECISION float brightboost;
uniform COMPAT_PRECISION float scanline;
uniform COMPAT_PRECISION float beam_min;
uniform COMPAT_PRECISION float beam_max;
uniform COMPAT_PRECISION float s_gamma;
uniform COMPAT_PRECISION float h_sharp;
uniform COMPAT_PRECISION float mask;
uniform COMPAT_PRECISION float maskstr;
uniform COMPAT_PRECISION float masksize;
uniform COMPAT_PRECISION float glow;
uniform COMPAT_PRECISION float gamma_out;
#else
#define brightboost 0.00 // smart Y integer scaling
#define brightboost 1.15 // adjust brightness
#define scanline 8.00 // scanline param, vertical sharpness
#define beam_min 1.35 // dark area beam min - narrow
#define beam_max 1.05 // bright area beam max - wide
#define s_gamma 2.40 // scanline gamma
#define h_sharp 1.25 // pixel sharpness
#define mask 0.00 // crt mask
#define maskstr 0.15 // raw crt mask strength
#define masksize 1.00 // crt mask size
#define glow 0.05 // glow strength
#define gamma_out 2.40 // gamma out
#endif
float st(float x)
{
return exp2(-scanline*x*x);
}
vec3 sw(float x, vec3 color)
{
vec3 tmp = mix(vec3(2.75*beam_min),vec3(beam_max), color);
tmp = mix(vec3(beam_max), tmp, pow(vec3(x), color+0.3));
vec3 ex = vec3(x)*tmp;
return exp2(-scanline*ex*ex)/(0.65 + 0.35*color);
}
float Overscan(float pos, float dy){
pos=pos*2.0-1.0;
pos*=dy;
return pos*0.5+0.5;
}
void main()
{
vec2 tex = TEX0.xy * 1.000001;
if (smart == 1.0)
{
float factor = OutputSize.y/InputSize.y;
float intfactor = round(factor);
float diff = factor/intfactor;
tex.y = Overscan(tex.y*(SourceSize.y/InputSize.y), diff)*(InputSize.y/SourceSize.y);
}
vec2 OGL2Pos = tex * SourceSize.xy - vec2(0.5);
vec2 fp = fract(OGL2Pos);
vec2 pC4 = (floor(OGL2Pos) + vec2(0.5)) * SourceSize.zw;
// Reading the texels
vec3 ul = COMPAT_TEXTURE(PassPrev4Texture, pC4 ).xyz; ul*=ul;
vec3 ur = COMPAT_TEXTURE(PassPrev4Texture, pC4 + vec2(SourceSize.z,0.0)).xyz; ur*=ur;
vec3 dl = COMPAT_TEXTURE(PassPrev4Texture, pC4 + vec2(0.0,SourceSize.w)).xyz; dl*=dl;
vec3 dr = COMPAT_TEXTURE(PassPrev4Texture, pC4 + SourceSize.zw ).xyz; dr*=dr;
float lx = fp.x; lx = pow(lx, h_sharp);
float rx = 1.0 - fp.x; rx = pow(rx, h_sharp);
float w = 1.0/(lx+rx);
vec3 color1 = w*(ur*lx + ul*rx);
vec3 color2 = w*(dr*lx + dl*rx);
ul*=ul*ul; ul*=ul;
ur*=ur*ur; ur*=ur;
dl*=dl*dl; dl*=dl;
dr*=dr*dr; dr*=dr;
vec3 scolor1 = w*(ur*lx + ul*rx); scolor1 = pow(scolor1, vec3(s_gamma*(1.0/12.0)));
vec3 scolor2 = w*(dr*lx + dl*rx); scolor2 = pow(scolor2, vec3(s_gamma*(1.0/12.0)));
// calculating scanlines
float f = fp.y;
float t1 = st(f);
float t2 = st(1.0-f);
vec3 color = color1*t1 + color2*t2;
vec3 scolor = scolor1*t1 + scolor2*t2;
vec3 ctemp = color / (t1 + t2);
vec3 sctemp = scolor / (t1 + t2);
vec3 cref1 = mix(scolor1, sctemp, 0.35);
vec3 cref2 = mix(scolor2, sctemp, 0.35);
vec3 w1 = sw(f,cref1);
vec3 w2 = sw(1.0-f,cref2);
color = color1*w1 + color2*w2;
color = min(color, 1.0);
vec3 scan3 = vec3(0.0);
float spos = floor((gl_FragCoord.x * 1.000001)/masksize); float spos1 = 0.0;
vec3 tmp1 = 0.5*(ctemp+sqrt(ctemp));
if (mask == 0.0)
{
spos1 = fract(spos*0.5);
if (spos1 < 0.5) scan3.rb = color.rb;
else scan3.g = color.g;
}
else
if (mask == 1.0)
{
spos1 = fract(spos*0.5);
if (spos1 < 0.5) scan3.rg = color.rg;
else scan3.b = color.b;
}
else
if (mask == 2.0)
{
spos1 = fract(spos/3.0);
if (spos1 < 0.333) scan3.r = color.r;
else if (spos1 < 0.666) scan3.g = color.g;
else scan3.b = color.b;
}
else
if (mask == 3.0)
{
spos1 = fract(spos*0.25);
if (spos1 < 0.25) scan3.r = color.r;
else if (spos1 < 0.50) scan3.rg = color.rg;
else if (spos1 < 0.75) scan3.gb = color.gb;
else scan3.b = color.b;
}
else
{
spos1 = fract(spos*0.25);
if (spos1 < 0.25) scan3.r = color.r;
else if (spos1 < 0.50) scan3.rb = color.rb;
else if (spos1 < 0.75) scan3.gb = color.gb;
else scan3.g = color.g;
}
color = mix(1.15*scan3, color, (1.0-maskstr)*tmp1)*(1.0 + 0.15*maskstr);
color*=brightboost;
float corr = (max(max(color.r,color.g),color.b) + 0.0001);
if (corr < 1.0) corr = 1.0;
color = color/corr;
vec3 Bloom = COMPAT_TEXTURE(Texture, tex).xyz;
color+= Bloom*glow;
color = pow(color, vec3(1.0/gamma_out));
FragColor = vec4(color, 1.0);
}
#endif
```

crt-guest-sm-glow.glslp

```
shaders = 5
shader0 = shaders/guest/d65-d50.glsl
filter_linear0 = false
scale_type0 = source
scale0 = 1.0
shader1 = shaders/guest/linearize.glsl
filter_linear1 = false
scale_type1 = source
scale1 = 1.0
float_framebuffer1 = true
shader2 = shaders/guest/blur_horiz.glsl
filter_linear2 = false
scale_type2 = source
scale2 = 1.0
float_framebuffer2 = true
shader3 = shaders/guest/blur_vert.glsl
filter_linear3 = true
scale_type3 = source
scale3 = 1.0
float_framebuffer3 = true
shader4 = shaders/guest/crt-guest-sm-glow.glsl
filter_linear4 = true
```

Hey man, thanks. Some content’s really look better with something like this…
The story started with the overscan shader for some PSX games and luckily i toyed with a (homemade) crt shader that simply needed integer scaling.