hmmm

learning/PixelSpirit/the_hermit.frag

@@ -0,0 +1,50 @@
+#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 triSDF(vec2 st) {
+  st = (st*2.-1.)*2.;
+  return max(abs(st.x)*.866025+st.y*.5,-st.y*.5);
+}
+
+float rhombSDF(vec2 st) {
+  vec2 st1 = (st*2.-1.)*2.;
+  vec2 st2 = (vec2(st.x,1.-st.y)*2.-1.)*2.;
+  float triangle1 = max(abs(st1.x)*.866025+st1.y*.5,-st1.y*.5);
+  float triangle2 = max(abs(st2.x)*.866025+st2.y*.5,-st2.y*.5);
+  return max(triangle1, triangle2);
+}
+
+float fill(float x, float size) {
+  return 1.-step(size, x);
+}
+
+float flip(float v, float pct) {
+  return mix(v, 1.-v, pct);
+}
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  vec3 color = vec3(0.0,0.0,0.0);
+  float alpha = 1.0;
+
+  float tri = fill(triSDF(st),.5);
+  float rhomb = fill(rhombSDF(st),.4);
+  color += flip(rhomb,tri);
+  gl_FragColor = vec4(color, alpha);
+}