Kuwahara Shader

FrankTheApe

This is a converted shadertoy shader from https://www.shadertoy.com/view/MsXSz4

The Kuwahara filter can be used as an Sprite or post-processing effect. Just add it to an Sprite2D or TextureRect node and add an input texture. The offset can also be used to tint the canvas.

See more about this shader
Shader code
shader_type canvas_item;
uniform int radius = 5;
uniform vec3 offset=vec3(0.0);
void fragment() 
 {
     vec2 src_size = vec2 ( SCREEN_PIXEL_SIZE.x,  SCREEN_PIXEL_SIZE.y);
     vec2 uv = UV.xy;
     float n = float((radius + 1) * (radius + 1));
     vec3 m0 = offset; vec3 m1 = offset; vec3 m2 = offset; vec3 m3 = offset;
     vec3 s0 = offset; vec3 s1 = offset; vec3 s2 = offset; vec3 s3 = offset;
     vec3 c;

     for (int j = -radius; j <= 0; ++j)  {
         for (int i = -radius; i <= 0; ++i)  {
             c = texture(TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m0 += c;
             s0 += c * c;
         }
     }

     for (int j = -radius; j <= 0; ++j)  {
         for (int i = 0; i <= radius; ++i)  {
             c = texture(TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m1 += c;
             s1 += c * c;
         }
     }

     for (int j = 0; j <= radius; ++j)  {
         for (int i = 0; i <= radius; ++i)  {
             c = texture(TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m2 += c;
             s2 += c * c;
         }
     }

     for (int j = 0; j <= radius; ++j)  {
         for (int i = -radius; i <= 0; ++i)  {
             c = texture(TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m3 += c;
             s3 += c * c;
         }
     }


     float min_sigma2 = 1e+2;
     m0 /= n;
     s0 = abs(s0 / n - m0 * m0);

     float sigma2 = s0.r + s0.g + s0.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m0, 1.0);
     }

     m1 /= n;
     s1 = abs(s1 / n - m1 * m1);

     sigma2 = s1.r + s1.g + s1.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m1, 1.0);
     }

     m2 /= n;
     s2 = abs(s2 / n - m2 * m2);

     sigma2 = s2.r + s2.g + s2.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m2, 1.0);
     }

     m3 /= n;
     s3 = abs(s3 / n - m3 * m3);

     sigma2 = s3.r + s3.g + s3.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m3, 1.0);
     }
 }
Tags
#shadertoy, effect, filter, kuwahra, Post processing, texture
This shader is a port from an existing Shadertoy project. Shadertoy shaders are by default protected under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0) license unless anything else has been stated by the author. For more info, see our License terms.

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vector
vector
3 years ago

this work on 3D projects ? i can’t manage to work. can you give an example ?

5
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FrankTheApe
FrankTheApe
2 years ago
Reply to  vector

it does. you need to to render your 3D game to an texturerect and apply the shader.

0
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GourabSN
GourabSN
1 year ago
Reply to  vector

Use this in the shader material in color rect

vGodot4.1.3

shader_type canvas_item;
uniform int radius = 5;
uniform vec3 offset=vec3(0.0);
uniform sampler2D SCREEN_TEXTURE : hint_screen_texture;

void fragment()
 {
     vec2 src_size = vec2 ( SCREEN_PIXEL_SIZE.x,  SCREEN_PIXEL_SIZE.y);
     vec2 uv = SCREEN_UV.xy;
     float n = float((radius + 1) * (radius + 1));
     vec3 m0 = offset; vec3 m1 = offset; vec3 m2 = offset; vec3 m3 = offset;
     vec3 s0 = offset; vec3 s1 = offset; vec3 s2 = offset; vec3 s3 = offset;
     vec3 c;

     for (int j = -radius; j <= 0; ++j)  {
         for (int i = -radius; i <= 0; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m0 += c;
             s0 += c * c;
         }
     }

     for (int j = -radius; j <= 0; ++j)  {
         for (int i = 0; i <= radius; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m1 += c;
             s1 += c * c;
         }
     }

     for (int j = 0; j <= radius; ++j)  {
         for (int i = 0; i <= radius; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m2 += c;
             s2 += c * c;
         }
     }

     for (int j = 0; j <= radius; ++j)  {
         for (int i = -radius; i <= 0; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m3 += c;
             s3 += c * c;
         }
     }


     float min_sigma2 = 1e+2;
     m0 /= n;
     s0 = abs(s0 / n - m0 * m0);

     float sigma2 = s0.r + s0.g + s0.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m0, 1.0);
     }

     m1 /= n;
     s1 = abs(s1 / n - m1 * m1);

     sigma2 = s1.r + s1.g + s1.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m1, 1.0);
     }

     m2 /= n;
     s2 = abs(s2 / n - m2 * m2);

     sigma2 = s2.r + s2.g + s2.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m2, 1.0);
     }

     m3 /= n;
     s3 = abs(s3 / n - m3 * m3);

     sigma2 = s3.r + s3.g + s3.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m3, 1.0);
     }
 }
1
Reply
Sendero
Sendero
1 year ago

What do you mean with add an input texture?

1
Reply
GourabSN
GourabSN
1 year ago
Reply to  Sendero

If u are using Godot 4 then use this code instead.

shader_type canvas_item;
uniform int radius = 5;
uniform vec3 offset=vec3(0.0);
uniform sampler2D SCREEN_TEXTURE : hint_screen_texture;

void fragment()
 {
     vec2 src_size = vec2 ( SCREEN_PIXEL_SIZE.x,  SCREEN_PIXEL_SIZE.y);
     vec2 uv = SCREEN_UV.xy;
     float n = float((radius + 1) * (radius + 1));
     vec3 m0 = offset; vec3 m1 = offset; vec3 m2 = offset; vec3 m3 = offset;
     vec3 s0 = offset; vec3 s1 = offset; vec3 s2 = offset; vec3 s3 = offset;
     vec3 c;

     for (int j = -radius; j <= 0; ++j)  {
         for (int i = -radius; i <= 0; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m0 += c;
             s0 += c * c;
         }
     }

     for (int j = -radius; j <= 0; ++j)  {
         for (int i = 0; i <= radius; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m1 += c;
             s1 += c * c;
         }
     }

     for (int j = 0; j <= radius; ++j)  {
         for (int i = 0; i <= radius; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m2 += c;
             s2 += c * c;
         }
     }

     for (int j = 0; j <= radius; ++j)  {
         for (int i = -radius; i <= 0; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m3 += c;
             s3 += c * c;
         }
     }


     float min_sigma2 = 1e+2;
     m0 /= n;
     s0 = abs(s0 / n - m0 * m0);

     float sigma2 = s0.r + s0.g + s0.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m0, 1.0);
     }

     m1 /= n;
     s1 = abs(s1 / n - m1 * m1);

     sigma2 = s1.r + s1.g + s1.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m1, 1.0);
     }

     m2 /= n;
     s2 = abs(s2 / n - m2 * m2);

     sigma2 = s2.r + s2.g + s2.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m2, 1.0);
     }

     m3 /= n;
     s3 = abs(s3 / n - m3 * m3);

     sigma2 = s3.r + s3.g + s3.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m3, 1.0);
     }
 }
0
Reply
GourabSN
GourabSN
1 year ago

This doesn’t work in Godot 4, so I made some changes.
CanvasLayer >> ColorRect >> Material>>ShaderMaterial>>Paste this Code

shader_type canvas_item;
uniform int radius = 5;
uniform vec3 offset=vec3(0.0);
uniform sampler2D SCREEN_TEXTURE : hint_screen_texture;

void fragment()
 {
     vec2 src_size = vec2 ( SCREEN_PIXEL_SIZE.x,  SCREEN_PIXEL_SIZE.y);
     vec2 uv = SCREEN_UV.xy;
     float n = float((radius + 1) * (radius + 1));
     vec3 m0 = offset; vec3 m1 = offset; vec3 m2 = offset; vec3 m3 = offset;
     vec3 s0 = offset; vec3 s1 = offset; vec3 s2 = offset; vec3 s3 = offset;
     vec3 c;

     for (int j = -radius; j <= 0; ++j)  {
         for (int i = -radius; i <= 0; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m0 += c;
             s0 += c * c;
         }
     }

     for (int j = -radius; j <= 0; ++j)  {
         for (int i = 0; i <= radius; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m1 += c;
             s1 += c * c;
         }
     }

     for (int j = 0; j <= radius; ++j)  {
         for (int i = 0; i <= radius; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m2 += c;
             s2 += c * c;
         }
     }

     for (int j = 0; j <= radius; ++j)  {
         for (int i = -radius; i <= 0; ++i)  {
             c = texture(SCREEN_TEXTURE, uv + vec2(float(i),float(j)) * src_size).rgb;
             m3 += c;
             s3 += c * c;
         }
     }


     float min_sigma2 = 1e+2;
     m0 /= n;
     s0 = abs(s0 / n - m0 * m0);

     float sigma2 = s0.r + s0.g + s0.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m0, 1.0);
     }

     m1 /= n;
     s1 = abs(s1 / n - m1 * m1);

     sigma2 = s1.r + s1.g + s1.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m1, 1.0);
     }

     m2 /= n;
     s2 = abs(s2 / n - m2 * m2);

     sigma2 = s2.r + s2.g + s2.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m2, 1.0);
     }

     m3 /= n;
     s3 = abs(s3 / n - m3 * m3);

     sigma2 = s3.r + s3.g + s3.b;
     if (sigma2 < min_sigma2) {
         min_sigma2 = sigma2;
         COLOR = vec4(m3, 1.0);
     }
 }
1
Reply
Jeroen
Jeroen
1 year ago
Reply to  GourabSN

Hey, this doesn’t seem to work, I just get a blank image instead of the intended effect…

0
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