#ifdef GL_ES precision mediump float; #endif uniform vec2 u_resolution; void main(){ vec2 st = gl_FragCoord.xy/u_resolution.xy; st.x *= u_resolution.x/u_resolution.y; vec3 color = vec3(0.0); float d = 0.0; // Remap the space to -1. to 1. st = st *2.-1.; // Make the distance field d = length(st)+length(min(st,0.))+length(max(st,0.)); // Visualize the distance field gl_FragColor = vec4(vec3(fract(d*10.0)),1.0); }