From fb117cf4a33a814785b92e77c19a6913cbd2da1a Mon Sep 17 00:00:00 2001
From: teridax <sven.vogel123@web.de>
Date: Sat, 3 Jun 2023 17:01:52 +0200
Subject: [PATCH] added blur-filter

---
 blur-filter/Buffer A.glsl |  31 ++++++++++
 blur-filter/Image.glsl    | 124 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 155 insertions(+)
 create mode 100644 blur-filter/Buffer A.glsl
 create mode 100644 blur-filter/Image.glsl

diff --git a/blur-filter/Buffer A.glsl b/blur-filter/Buffer A.glsl
new file mode 100644
index 0000000..2df4fce
--- /dev/null
+++ b/blur-filter/Buffer A.glsl	
@@ -0,0 +1,31 @@
+
+float luminance(in vec3 srgb)
+{
+    return dot(srgb, vec3(0.2126, 0.7152, 0.0722));
+}
+
+float falloff(in float lum)
+{
+    float sq = lum * lum;
+    return sq * sq - 2.0 * sq + 1.0;
+}
+
+vec3 mix_with_noise(inout vec3 col, in vec2 uv)
+{
+    vec3 noise = texture(iChannel1, uv).rgb;
+
+    float fac = falloff(luminance(col) * 2.0 - 1.0);
+
+    return mix(col, noise, fac * 0.5) * pow(noise, vec3(0.2));
+}
+
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    vec2 uv = fragCoord/iResolution.xy;
+
+    vec3 imageCol = texture(iChannel0, uv).rgb;
+
+    vec3 col = pow(imageCol * mix_with_noise(imageCol, uv * 2.0), vec3(0.5));
+
+    fragColor = vec4(col, 1.0);
+}
diff --git a/blur-filter/Image.glsl b/blur-filter/Image.glsl
new file mode 100644
index 0000000..d268de8
--- /dev/null
+++ b/blur-filter/Image.glsl
@@ -0,0 +1,124 @@
+
+const float PI = 3.141592653589793;
+
+// --------------------------------------------------------------------
+// Gaussian-Blur
+// --------------------------------------------------------------------
+
+const float INV_PI = 0.3183098861837907;
+
+float gaussianSpaceWeight(in vec2 xy, in float sigma)
+{
+    float twoSqSigma = 1.0 / (2.0 * sigma * sigma);
+    return exp(-dot(xy,xy) * twoSqSigma) * twoSqSigma * INV_PI;
+}
+
+vec3 gaussianBlur(in vec2 uv, in sampler2D tex, in float sigma)
+{
+    int radius = int(ceil(5.0 * sigma)*0.5);
+
+    vec2 scale = 1.0 / vec2(textureSize(tex, 0));
+
+    vec3 sum = vec3(0);
+
+    for (int x = -radius; x <= radius; x++)
+    for (int y = -radius; y <= radius; y++)
+    {
+        vec2 off = vec2(x, y) * scale;
+
+        float w = gaussianSpaceWeight(vec2(x, y), sigma);
+
+        vec3 col = texture(tex, uv + off).rgb * w;
+
+        sum += col;
+    }
+
+    return sum;
+}
+
+// --------------------------------------------------------------------
+// Tent-Blur
+// --------------------------------------------------------------------
+
+float tentKernel(in vec2 xy, in float r)
+{
+    return (1.0 - abs(xy.x/r)) * (1.0 - abs(xy.y/r)) / (r*r);
+}
+
+vec3 tentBlur(in vec2 uv, in sampler2D tex, in int r)
+{
+
+    vec2 scale = 1.0 / vec2(textureSize(tex, 0));
+
+    vec3 sum = vec3(0);
+
+    for (int x = -r; x <= r; x++)
+    for (int y = -r; y <= r; y++)
+    {
+        vec2 off = vec2(x, y) * scale;
+
+        float w = tentKernel(vec2(x, y), float(r));
+
+        vec3 col = texture(tex, uv + off).rgb * w;
+
+        sum += col;
+    }
+
+    return sum;
+}
+
+// --------------------------------------------------------------------
+// Tent-Blur
+// --------------------------------------------------------------------
+
+vec3 boxBlur(in vec2 uv, in sampler2D tex, in int r)
+{
+
+    vec2 scale = 1.0 / vec2(textureSize(tex, 0));
+
+    vec3 sum = vec3(0);
+
+    for (int x = -r; x <= r; x++)
+    for (int y = -r; y <= r; y++)
+    {
+        vec2 off = vec2(x, y) * scale;
+
+        vec3 col = texture(tex, uv + off).rgb;
+
+        sum += col;
+    }
+
+    return sum / float((2*r+1)*(2*r+1));
+}
+
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    // Normalized pixel coordinates (from 0 to 1)
+    vec2 uv = fragCoord/iResolution.xy;
+
+    vec3 col;
+
+    if (uv.x > 0.75)
+    {
+        col = gaussianBlur(uv, iChannel0, 4.0);
+    }
+    else if (uv.x > 0.5 && uv.x < 0.75)
+    {
+        col = tentBlur(uv, iChannel0, 8);
+    }
+    else if(uv.x > 0.25 && uv.x < 0.5)
+    {
+        col = boxBlur(uv, iChannel0, 4);
+    }
+    else
+    {
+        col = texture(iChannel0, uv).rgb;
+    }
+
+    float border = abs(sin(uv.x*PI*4.0));
+
+    col *= step(0.03, border);
+
+    // Output to screen
+    fragColor = vec4(col,1.0);
+}