precision mediump float;
// Created by inigo quilez - iq/2013
// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

uniform vec3 iResolution; // viewport resolution (in pixels)
uniform float iGlobalTime; // shader playback time (in seconds)
uniform vec4 iMouse; // mouse pixel coords. xy: current pixel coords. zw = click pixel
uniform vec4 iDate; // (year, month, day, time in seconds)

float sdSegment( in vec2 p, in vec2 a, in vec2 b )
{
	vec2 pa = p-a, ba = b-a;
	float h = clamp( dot(pa,ba)/dot(ba,ba), 0.0, 1.0 );
	return length( pa - ba*h );