ksnap het nog nie volledig

learning/patterns/offset.frag

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+#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)); }
+
+vec2 brickTile(vec2 st, float zoom) {
+  st *= zoom;
+  st.x += step(1., mod(st.y,2.)) * .5;
+  return fract(st);
+}
+
+float rectSDF(vec2 st, vec2 s) {
+  return max(abs(st.x/s.x),abs(st.y/s.y));
+}
+
+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;
+  
+  st = brickTile(st, 5.) - .5;
+  color += rectSDF(st, vec2(1.));
+  
+
+  gl_FragColor = vec4(color, alpha);
+}

learning/patterns/truchet_tiles.frag

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+#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)); }
+
+vec2 rotate(vec2 st, float a) {
+  return mat2(cos(a),-sin(a),sin(a),cos(a))*(st);
+}
+
+vec2 rotateTilePattern(vec2 st) {
+  st *= 2.;
+
+  // give each cell an index number according to its position
+  float index = .0;
+  index += step(1., mod(st.x,2.));
+  index += step(1., mod(st.y,2.))*2.;
+
+  // 2 3
+  // 0 1
+
+  st = fract(st);
+  st = rotate(st, radians(90.*index));
+
+  return st;
+}
+
+float triSDF(vec2 st) {
+  st = st*2.;
+  return max(abs(st.x)*.866025+st.y*.5,-st.y*.5);
+}
+
+vec2 tile(vec2 st, float tiles) {return fract(st*tiles)-.5; }
+
+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;
+  st = tile(st, 3.);
+  st = rotateTilePattern(st);
+  st -= .5;
+  color += triSDF(st);
+
+  gl_FragColor = vec4(color, alpha);
+}