Add glow stuff with flutter

pubspec.lock

@@ -5,23 +5,18 @@ packages:
     dependency: transitive
     description:
       name: _fe_analyzer_shared
-      sha256: "5aaf60d96c4cd00fe7f21594b5ad6a1b699c80a27420f8a837f4d68473ef09e3"
+      sha256: "0b2f2bd91ba804e53a61d757b986f89f1f9eaed5b11e4b2f5a2468d86d6c9fc7"
       url: "https://pub.dev"
     source: hosted
-    version: "68.0.0"
-  _macros:
-    dependency: transitive
-    description: dart
-    source: sdk
-    version: "0.1.5"
+    version: "67.0.0"
   analyzer:
     dependency: transitive
     description:
       name: analyzer
-      sha256: "21f1d3720fd1c70316399d5e2bccaebb415c434592d778cce8acb967b8578808"
+      sha256: "37577842a27e4338429a1cbc32679d508836510b056f1eedf0c8d20e39c1383d"
       url: "https://pub.dev"
     source: hosted
-    version: "6.5.0"
+    version: "6.4.1"
   archive:
     dependency: transitive
     description:
@@ -294,14 +289,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.2.0"
-  macros:
-    dependency: transitive
-    description:
-      name: macros
-      sha256: a8403c89b36483b4cbf9f1fcd24562f483cb34a5c9bf101cf2b0d8a083cf1239
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.1.0-main.5"
   markdown:
     dependency: transitive
     description:
@@ -675,10 +662,10 @@ packages:
     dependency: transitive
     description:
       name: win32
-      sha256: a79dbe579cb51ecd6d30b17e0cae4e0ea15e2c0e66f69ad4198f22a6789e94f4
+      sha256: "0eaf06e3446824099858367950a813472af675116bf63f008a4c2a75ae13e9cb"
       url: "https://pub.dev"
     source: hosted
-    version: "5.5.1"
+    version: "5.5.0"
   xml:
     dependency: transitive
     description:
@@ -696,4 +683,4 @@ packages:
     source: hosted
     version: "3.1.2"
 sdks:
-  dart: ">=3.4.0 <4.0.0"
+  dart: ">=3.3.0 <4.0.0"

source/shaders/glow-stuff/index.md

@@ -0,0 +1,104 @@
+---
+description: Glowing text, image and eve rive animations with a shader.
+shader:
+  title: Glow stuff
+  description: A glowing effect that can plug into actual flutter layouts and create a mesmerizing effect
+  screenshot: space.png
+  video: scrolling.mp4
+directory: shaders/glow-stuff/
+---
+
+
+```glsl
+// Directional glow GLSL fragment shader.
+// Based on the "Let it Glow!" pen by "Selman Ay" (https://codepen.io/selmanays/pen/yLVmEqY)
+// Functioning example at: https://github.com/renancaraujo/glow_stuff_with_flutter
+precision highp float;
+
+// Float uniforms
+uniform float width; // Width of the canvas
+uniform float height; // Height of the canvas
+uniform float sourceX; // X position of the light source
+uniform float scrollFraction; // Scroll fraction of the page in relation to the canvas
+uniform float density; // Density of the "smoke" effect
+uniform float lightStrength; // Strength of the light
+uniform float weight; // Weight of the "smoke" effect
+
+// Sampler uniforms
+uniform sampler2D tInput; // Input texture (the application canvas)
+uniform sampler2D tNoise; // Some texture
+
+out vec4 fragColor;
+
+float sourceY = scrollFraction;
+vec2 resolution = vec2(width, height);
+vec2 lightSource = vec2(sourceX, sourceY);
+
+const int samples = 20; // The number of "copies" of the canvas made to emulate the "smoke" effect
+const float decay = 0.88; // Decay of the light in each sample
+const float exposure = .9; // The exposure to the light
+
+
+float random2d(vec2 uv) {
+    uv /= 256.;
+    vec4 tex = texture(tNoise, uv);
+    return mix(tex.r, tex.g, tex.a);
+}
+
+float random(vec3 xyz){
+    return fract(sin(dot(xyz, vec3(12.9898, 78.233, 151.7182))) * 43758.5453);
+}
+
+vec4 sampleTexture(vec2 uv) {
+    vec4 textColor = texture(tInput, uv);
+    return textColor;
+}
+
+vec4 occlusion(vec2 uv, vec2 lightpos, vec4 objects) {
+    return (1. - smoothstep(0.0, lightStrength, length(lightpos - uv))) * (objects);
+}
+
+
+vec4 fragment(vec2 uv, vec2 fragCoord) {
+    vec3 colour = vec3(0);
+
+    vec4 obj = sampleTexture(uv);
+    vec4 map = occlusion(uv, lightSource, obj);
+
+    float random = random(vec3(fragCoord, 1.0));;
+
+    float exposure = exposure + (sin(random) * .5 + 1.) * .05;
+
+    vec2 _uv = uv;
+    vec2 distance = (_uv - lightSource) * (1. / float(samples) * density);
+
+    float illumination_decay = 1.;
+    for (int i=0; i<samples; i++) {
+        _uv -= distance;
+
+        float movement = random * 20. * float(i + 1);
+        float dither = random2d(uv + mod(vec2(movement*sin(random * .5), -movement), 1000.)) * 2.;
+
+        vec4 stepped_map = occlusion(uv, lightSource, sampleTexture(_uv+distance*dither));
+        stepped_map *= illumination_decay * weight;
+
+        illumination_decay *= decay;
+        map += stepped_map;
+    }
+
+    float lum = dot(map.rgb, vec3(0.2126, 0.7152, 0.0722));
+
+    colour += vec3(map.rgb*exposure);
+    return vec4(colour, lum);
+}
+
+void main() {
+    vec2 pos = gl_FragCoord.xy;
+    vec2 uv = pos / vec2(width, height);
+    fragColor = fragment(uv, pos);
+}
+
+```
+
+
+More explanation here: [tweet](https://x.com/reNotANumber/status/1599717360096620544).