Hex packing shader for shadertoy

Hex pack shader

float hex(vec2 p) {
  p.x *= 0.57735*2.0;
	p.y += mod(floor(p.x), 2.0)*0.5;
	p = abs((mod(p, 1.0) - 0.5));
	return abs(max(p.x*1.5 + p.y, p.y*2.0) - 1.0);
}

void mainImage(out vec4 fragColor, in vec2 fragCoord) { 
	vec2 pos = fragCoord.xy;
	vec2 p = pos/20.0; 
	float  r = (1.0 -0.7)*0.5;	
	fragColor = vec4(smoothstep(0.0, r + 0.05, hex(p)));
}