slang-shaders/crt/crt-easymode.slang

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#version 450
layout(std140, set = 0, binding = 0) uniform UBO
{
mat4 MVP;
vec4 OutputSize; /* .xy is Cg equivalent of output_size */
vec4 OriginalSize;
vec4 SourceSize; /* .xy is Cg equivalent of both texture_size and video_size */
} 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;
}
/*
CRT Shader by EasyMode
License: GPL
A flat CRT shader ideally for 1080p or higher displays.
Recommended Settings:
Video
- Aspect Ratio: 4:3
- Integer Scale: Off
Shader
- Filter: Nearest
- Scale: Don't Care
Example RGB Mask Parameter Settings:
Aperture Grille (Default)
- Dot Width: 1
- Dot Height: 1
- Stagger: 0
Lottes' Shadow Mask
- Dot Width: 2
- Dot Height: 1
- Stagger: 3
*/
#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 1) in vec2 FragCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;
#define SHARPNESS_H 0.5
#define SHARPNESS_V 1.0
#define MASK_STRENGTH 0.3
#define MASK_DOT_WIDTH 1.0
#define MASK_DOT_HEIGHT 1.0
#define MASK_STAGGER 0.0
#define MASK_SIZE 1.0
#define SCANLINE_STRENGTH 1.0
#define SCANLINE_BEAM_WIDTH_MIN 1.5
#define SCANLINE_BEAM_WIDTH_MAX 1.5
#define SCANLINE_BRIGHT_MIN 0.35
#define SCANLINE_BRIGHT_MAX 0.65
#define SCANLINE_CUTOFF 400.0
#define GAMMA_INPUT 2.0
#define GAMMA_OUTPUT 1.8
#define BRIGHT_BOOST 1.2
#define DILATION 1.0
#define FIX(c) max(abs(c), 1e-5)
#define PI 3.141592653589
#define TEX2D(c) dilate(texture(Source, c))
// Set to 0 to use linear filter and gain speed
#define ENABLE_LANCZOS 1
vec4 dilate(vec4 col)
{
vec4 x = mix(vec4(1.0), col, DILATION);
return col * x;
}
float curve_distance(float x, float sharp)
{
/*
apply half-circle s-curve to distance for sharper (more pixelated) interpolation
single line formula for Graph Toy:
0.5 - sqrt(0.25 - (x - step(0.5, x)) * (x - step(0.5, x))) * sign(0.5 - x)
*/
float x_step = step(0.5, x);
float curve = 0.5 - sqrt(0.25 - (x - x_step) * (x - x_step)) * sign(0.5 - x);
return mix(x, curve, sharp);
}
mat4x4 get_color_matrix(sampler2D tex, vec2 co, vec2 dx)
{
return mat4x4(TEX2D(co - dx), TEX2D(co), TEX2D(co + dx), TEX2D(co + 2.0 * dx));
}
vec3 filter_lanczos(vec4 coeffs, mat4x4 color_matrix)
{
vec4 col = coeffs * color_matrix;
vec4 sample_min = min(color_matrix[1], color_matrix[2]);
vec4 sample_max = max(color_matrix[1], color_matrix[2]);
col = clamp(col, sample_min, sample_max);
return col.rgb;
}
/* main_fragment */
void main()
{
vec2 dx = vec2(1.0 / global.SourceSize.x, 0.0);
vec2 dy = vec2(0.0, 1.0 / global.SourceSize.y);
vec2 pix_co = vTexCoord * global.SourceSize.xy - vec2(0.5, 0.5);
vec2 tex_co = (floor(pix_co) + vec2(0.5, 0.5)) / global.SourceSize.xy;
vec2 dist = fract(pix_co);
float curve_x;
vec3 col, col2;
#if ENABLE_LANCZOS
curve_x = curve_distance(dist.x, SHARPNESS_H * SHARPNESS_H);
vec4 coeffs = PI * vec4(1.0 + curve_x, curve_x, 1.0 - curve_x, 2.0 - curve_x);
coeffs = FIX(coeffs);
coeffs = 2.0 * sin(coeffs) * sin(coeffs / 2.0) / (coeffs * coeffs);
coeffs /= dot(coeffs, vec4(1.0));
col = filter_lanczos(coeffs, get_color_matrix(Source, tex_co, dx));
col2 = filter_lanczos(coeffs, get_color_matrix(Source, tex_co + dy, dx));
#else
curve_x = curve_distance(dist.x, SHARPNESS_H);
col = mix(TEX2D(tex_co).rgb, TEX2D(tex_co + dx).rgb, curve_x);
col2 = mix(TEX2D(tex_co + dy).rgb, TEX2D(tex_co + dx + dy).rgb, curve_x);
#endif
col = mix(col, col2, curve_distance(dist.y, SHARPNESS_V));
col = pow(col, vec3(GAMMA_INPUT / (DILATION + 1.0)));
float luma = dot(vec3(0.2126, 0.7152, 0.0722), col);
float bright = (max(col.r, max(col.g, col.b)) + luma) / 2.0;
float scan_bright = clamp(bright, SCANLINE_BRIGHT_MIN, SCANLINE_BRIGHT_MAX);
float scan_beam = clamp(bright * SCANLINE_BEAM_WIDTH_MAX, SCANLINE_BEAM_WIDTH_MIN, SCANLINE_BEAM_WIDTH_MAX);
float scan_weight = 1.0 - pow(cos(vTexCoord.y * 2.0 * PI * global.SourceSize.y) * 0.5 + 0.5, scan_beam) * SCANLINE_STRENGTH;
float mask = 1.0 - MASK_STRENGTH;
vec2 mod_fac = floor(vTexCoord * global.OutputSize.xy * global.SourceSize.xy / (global.SourceSize.xy * vec2(MASK_SIZE, MASK_DOT_HEIGHT * MASK_SIZE)));
int dot_no = int(mod((mod_fac.x + mod(mod_fac.y, 2.0) * MASK_STAGGER) / MASK_DOT_WIDTH, 3.0));
vec3 mask_weight;
if (dot_no == 0) mask_weight = vec3(1.0, mask, mask);
else if (dot_no == 1) mask_weight = vec3(mask, 1.0, mask);
else mask_weight = vec3(mask, mask, 1.0);
if (global.SourceSize.y >= SCANLINE_CUTOFF) scan_weight = 1.0;
col2 = col.rgb;
col *= vec3(scan_weight);
col = mix(col, col2, scan_bright);
col *= mask_weight;
col = pow(col, vec3(1.0 / GAMMA_OUTPUT));
FragColor = vec4(col * BRIGHT_BOOST, 1.0);
}