From 7a11b315bb255ea8e7d1f38ccc4dc6cac5b3f6d6 Mon Sep 17 00:00:00 2001
From: beppe <beppe.vanrolleghem@gmail.com>
Date: Sat, 4 May 2024 21:20:12 +0200
Subject: [PATCH] this is so hard

---
 learning/shapes/box.frag   |  2 +-
 learning/shapes/polar.frag | 40 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 learning/shapes/polar.frag

diff --git a/learning/shapes/box.frag b/learning/shapes/box.frag
index e819f68..fa4b33d 100644
--- a/learning/shapes/box.frag
+++ b/learning/shapes/box.frag
@@ -1,4 +1,4 @@
-#ifdef GL_ES
+ #ifdef GL_ES
 precision mediump float;
 #endif
 
diff --git a/learning/shapes/polar.frag b/learning/shapes/polar.frag
new file mode 100644
index 0000000..d1f1248
--- /dev/null
+++ b/learning/shapes/polar.frag
@@ -0,0 +1,40 @@
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform vec2 u_resolution;
+uniform vec2 u_mouse;
+uniform float u_time;
+
+
+float plot(vec2 st, float pct) {
+  return smoothstep(pct-0.02, pct, st.y) - smoothstep(pct,pct+0.02, st.y);
+}
+
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution.xy;
+  vec3 color = vec3(0.0);
+  vec2 pos = vec2(0.5,0.5)-st;// these values map to the center of the circle function thing
+  
+  float r = length(pos)*5.; //increasing this value makes the circle smaller. but i don't understand why yet
+  float mod = floor(abs(sin(u_time)) * 100.) ;
+  float a = atan(pos.y,pos.x)*mod; 
+  // a seems to be responsible for the frequency of the function, like directly, the multing the output of the atan by 8 would mean 8 oscillations happen in the function. seems obvious now that i'm typing it out
+
+  float f = cos(a*1.0);
+  //f = abs(cos(a*3.));
+  //f = abs(cos(a*2.5))*.5+.3;
+  //f = abs(cos(a*12.)*sin(a*3.))*floor(fract(st.x/u_time + st.y/u_time)*20.)+.1;
+  //f = smoothstep(-.5,1., cos(a*10.))*0.2+0.5;
+
+  color = vec3(0.2,0.2,0.2);
+  //color = vec3(1.-smoothstep(f,f+0.2,r));
+  float pct = plot(vec2(f,f+0.2),r);
+  color = (1.0-pct)* color + pct * vec3(0.0,1.0,0.0);
+  // the first part (1.0-pct) * col is used to disable the underlying color when the pct is 0. with the other section adding then the wanted color on top.
+  gl_FragColor = vec4(color, 1.0);
+
+}
+
+