From 6219e51b0c7442a4068b9964862fb4cc658ac72b Mon Sep 17 00:00:00 2001
From: bvanroll <beppe.vanrolleghem@gmail.com>
Date: Sat, 22 Jun 2024 14:23:37 +0200
Subject: [PATCH] i got lazy

---
 learning/PixelSpirit/the_sun.frag | 41 ++++++++++++++++++++++++++++++-
 learning/random/2d_random.frag    | 38 ++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 1 deletion(-)
 create mode 100644 learning/random/2d_random.frag

diff --git a/learning/PixelSpirit/the_sun.frag b/learning/PixelSpirit/the_sun.frag
index d79139f..3054f3f 100644
--- a/learning/PixelSpirit/the_sun.frag
+++ b/learning/PixelSpirit/the_sun.frag
@@ -15,12 +15,51 @@ const vec3 uDColor = vec3(.0,.33,.67);
 //get colors from http://dev.thi.ng/gradients/
 vec3 cosPalette(float t) { return uAColor + uBColor*cos(6.28318*(uCColor*t+uDColor)); }
 
+vec2 rotate(vec2 st, float a) {
+  return mat2(cos(a),-sin(a),sin(a),cos(a))*(st);
+}
 
+float starSDF(vec2 st, float V, float s) {
+  st = st*4.;
+  float a = atan(st.y, st.x)/(2.*3.14159265359);
+  float seg = a * V;
+  a = ((floor(seg) + .5)/V + mix(s, -s,step(.5,fract(seg)))) * (2.*3.14159265359);
+  return abs(dot(vec2(cos(a),sin(a)),st));
+      
+}
+
+float fill(float x, float size) { return 1.-step(size, x); }
+
+float polySDF(vec2 st, float angles) {
+  float a = atan(st.x,st.y)+PI;
+  float r = length(st);
+  float v = (2.*PI)/angles;
+  return cos(floor(.5+a/v)*v-a)*r;
+}
+
+float stroke(in float x_coor, float s, float width){
+  float d = step(s,x_coor+width*.5)-step(s,x_coor-width*.5);
+  return clamp(d, 0.,1.);
+}
+
+// i got lazy
 void main() {
   vec2 st = (gl_FragCoord.xy*2. - u_resolution.xy)/u_resolution.y;
   vec3 color = vec3(0.0,0.0,0.0);
   float alpha = 1.0;
-
+  float bg = starSDF(st, 16., .1);
+  color += fill(bg,1.3);
+  float l = 0.;
+  for (float i = 0.; i< 8.; i++) {
+    vec2 xy = rotate(st, radians(180./4.)*i);
+    xy.y -= .3;
+    float tri = polySDF(xy, 3.);
+    color += fill(tri, .3);
+    l += stroke(tri, .3, .03);
+  }
+  color *= 1.-l;
+  float c = polySDF(st, 8.);
+  color -= stroke(c, .15, .04);
   
 
   gl_FragColor = vec4(color, alpha);
diff --git a/learning/random/2d_random.frag b/learning/random/2d_random.frag
new file mode 100644
index 0000000..ed6f762
--- /dev/null
+++ b/learning/random/2d_random.frag
@@ -0,0 +1,38 @@
+#ifdef GL_ES
+precision mediump float;
+#endif
+uniform vec2 u_resolution;
+uniform vec2 u_mouse;
+uniform float u_time;
+
+#define PI 3.14159265359
+
+const vec3 uAColor = vec3(.5,.5,.5);
+const vec3 uBColor = vec3(.5,.5,.5);
+const vec3 uCColor = vec3(1.,1.,1.);
+const vec3 uDColor = vec3(.0,.33,.67);
+
+//get colors from http://dev.thi.ng/gradients/
+vec3 cosPalette(float t) { return uAColor + uBColor*cos(6.28318*(uCColor*t+uDColor)); }
+
+float random (vec2 st) {
+  vec2 stm = u_mouse/u_resolution;
+  
+  return fract(sin(dot(st.xy*u_time, stm.xy))*43758.5453123);
+}
+
+
+void main() {
+  vec2 st = (gl_FragCoord.xy*2. - u_resolution.xy)/u_resolution.y;
+  st *= 10.0;
+  vec2 ios = floor(st);
+  vec2 fos = fract(st);
+  vec3 color = vec3(0.0,0.0,0.0);
+  float alpha = 1.0;
+  
+  color += random(ios);
+
+  
+
+  gl_FragColor = vec4(color, alpha);
+}