cool cool cool

learning/2d_matrices/translate.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)); }
+
+float crossSDF(vec2 st, float s) {
+  vec2 size = vec2(.25, s);
+  float rect1 = max(abs(st.x/size.x),abs(st.y/size.y));
+  float rect2 = max(abs(st.x/size.y),abs(st.y/size.x));
+  return min(rect1,rect2);
+}
+
+float fill(float x, float size) { return 1.-step(size, x); }
+
+void main() {
+  vec2 st = gl_FragCoord.xy/u_resolution;
+  st.x *= u_resolution.x/u_resolution.y;
+  st = (st-.5)*2.;
+  vec3 color = vec3(0.0,0.0,0.0);
+  float alpha = 1.0;
+  
+  vec2 translate = vec2(0.,sin(u_time));
+  st += translate*.35;
+  color = vec3(st.x,st.y,.0);
+  color += fill(crossSDF(st,1.),.2+(cos(u_time*2.)*.1));
+  gl_FragColor = vec4(color, alpha);
+}