i got lazy

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);