ik versta da met de polar coordinats nu denk ik

learning/PixelSpirit/bundle.frag

@@ -15,6 +15,7 @@ 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 hexSDF(vec2 st) {
   st = abs(st*2.-1.);
   return max(abs(st.y),st.x*.866025+st.y*.5);

learning/PixelSpirit/the_devil.frag

@@ -0,0 +1,45 @@
+#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 starSDF(vec2 st, int V, float s) {
+  st = st*4.-2.;
+  float a = atan(st.y, st.x)/(2.*PI);
+  float seg = a * float(V);
+  a = ((floor(seg) + .5)/float(V)+mix(s,-s,step(.5,fract(seg))))*(2.*PI);
+  return abs(dot(vec2(cos(a),sin(a)),st));
+}
+
+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.);
+}
+
+float circleSDF(vec2 st) { return length(st-.5)*2.; }
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  vec3 color = vec3(0.0,0.0,0.0);
+  float alpha = 1.0;
+  color += stroke(circleSDF(st),.8,.05);
+  st.y = 1.-st.y;
+  float s = starSDF(st.yx,5,.1);
+  color *= step(.7,s);
+  color += stroke(s,.4,.1);
+  
+
+  gl_FragColor = vec4(color, alpha);
+}

learning/shapes/polar_shapes.frag

@@ -0,0 +1,39 @@
+#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 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.);
+}
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  vec3 color = vec3(0.0,0.0,0.0);
+  float alpha = 1.0;
+  vec2 pos = vec2(.5)-st;
+  float r = length(pos)*2.;
+  float a = atan(pos.y,pos.x);
+  float f = sin(a*3.);
+  f = abs(cos(a*3.));
+  f = abs(cos(a*2.5))*.5+.3;
+  f = abs(cos(a*12.)*sin(a*3.))*.8+.1;
+  f = smoothstep(-.5,.8,cos(a*10.))*.2+.5;
+  color += 1.-stroke(f, 1.,.4);
+  
+
+  gl_FragColor = vec4(color, alpha);
+}

learning/shapes/polar_test.frag

@@ -0,0 +1,60 @@
+#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 circleSDF(vec2 st) { return length(st)*2.; }
+
+float rectSDF(vec2 st, vec2 s) {
+  st = st;
+  return max(abs(st.x/s.x),abs(st.y/s.y));
+}
+
+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.);
+}
+
+float polySDF(vec2 st, float angles) {
+//  st = st*2.-1.;
+  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;
+}
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  st *= u_resolution.x/u_resolution.y;
+  st = (st - .5)*2.;
+  vec3 color = vec3(0.0,0.0,0.0);
+  vec2 m = u_mouse.xy/u_resolution.xy;
+  m *= u_resolution.x/u_resolution.y;
+  m = abs(m);
+  float alpha = 1.0;
+  float fq = 2.;
+  float pos = radians(dot(m,m)*360.);
+  float c = circleSDF(st);
+  float r = rectSDF(st, vec2(1.));
+  float a = atan(st.y,st.x);
+  float f = (cos(a*fq+pos)/2.+.5)*.1;
+  float s = polySDF(st, 6.);
+  //a = abs(cos(a+u_time))*.1;
+  //a = mix(a, .1, sin(u_time));
+  color += stroke(s,.5,.1+f);
+  //color += c;
+  
+  gl_FragColor = vec4(color, alpha);
+}

learning/shapes/sdf.frag

@@ -0,0 +1,40 @@
+#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)); }
+
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  st.x *= u_resolution.x/u_resolution.y;
+  vec3 color = vec3(0.0,0.0,0.0);
+  float alpha = 1.0;
+
+  float d = 0.;
+  //remaps to -1 - 1;
+  st = st*2.-1.;
+
+  d = length(abs(st)-.3);
+  d = length(min(abs(st)-.3,0.));
+  d = length(max(abs(st)-.3,0.));
+  //color += fract(d*10.);
+  //color += vec3(step(.3,d));
+  //color += vec3(step(.3,d)*step(d,.4));
+  color += vec3(smoothstep(.3,.4,d)*smoothstep(.6,.5,d));
+
+  
+
+  gl_FragColor = vec4(color, alpha);
+}