---

/*{
	"IMPORTED": [],
	"CATEGORIES": [
		"Automatically Converted",
		"Shadertoy"
	],
	"DESCRIPTION": "Automatically converted from https://www.shadertoy.com/view/wtfXW2 by TekF.  Golden-ratio polar-coordinate distribution of points gives really uniform coverage for any number of points. Created this to test if it would make a good sampling pattern.",
	"INPUTS": [
		{
			"NAME": "n",
			"TYPE": "float",
			"DEFAULT": 800,
			"MIN": 0,
			"MAX": 800
		},
		{
			"NAME": "rate",
			"TYPE": "float",
			"DEFAULT": 7,
			"MIN": 0,
			"MAX": 20
		},
		{
			"NAME": "lineThickness",
			"TYPE": "float",
			"DEFAULT": 2.2,
			"MIN": 2,
			"MAX": 10
		},
		{
			"NAME": "colours",
			"TYPE": "float",
			"DEFAULT": 0.05,
			"MIN": 0,
			"MAX": 1
		},
		{
			"NAME": "zoom",
			"TYPE": "bool",
			"DEFAULT": true
		}
	]
}
*/


//const int n = 800;
//const float rate = 7.;
//const float lineThickness = 2.2;
//const float colours = 0.05; // proportion of cells to colour in
//const bool zoom = true;

const float phi = 1.6180339887498948;
const float tau = 6.2831853071795865;

void main() {



    vec2 uv = (gl_FragCoord.xy-RENDERSIZE.xy*.5)/RENDERSIZE.y;
    float penOut = lineThickness/RENDERSIZE.y;
    float penIn = (lineThickness-2.8)/RENDERSIZE.y;
    float t = TIME*rate;
    
    gl_FragColor = vec4(0,0,0,1);
    float scale = sqrt(float(n));
    if ( zoom ) scale = min( scale, pow((TIME+7.)*rate*.5,.6) ); // keep the edgemost points in shot as we zoom
    
    float closest = 1e38;
    float closest2 = 1e38;
    for ( int i=0; i < int(n); i++ )
    {
        float f = float(i);
        f += fract(t);
        float r = sqrt(f/128.);
        r *= 13./scale;
        float a = fract((f-t)*phi)*tau;
        vec2 pos = r*vec2(sin(a),cos(a));
        
        vec3 col = sin(vec3(3,1,6)*(float(i)-floor(t)))*.5+.5;
        if ( fract(col.y*64.) > colours ) col = vec3(1);
        float l = length(pos-uv);
        // add a ring to help me track size (so it doesn't look like we're zooming out)
        //col *= smoothstep(penIn,penOut,abs(l/scale-.001)*scale);
		
        if ( i == 0 ) l += smoothstep(1.,0.,fract(t))*1.2/scale; // grow the new point
		if ( l < closest )
        {
            if ( closest < closest2 ) closest2 = closest;
            closest = l;
			gl_FragColor.rgb = col; // *(1.-l*sqrt(float(n)));
        }
        else if ( l < closest2 )
        {
            closest2 = l;
        }
        gl_FragColor.rgb = mix(gl_FragColor.rgb,vec3(0),smoothstep(penOut,penIn,length(pos-uv)));
    }
    
    // cell borders
    gl_FragColor.rgb *= smoothstep(penIn,penOut,(closest2-closest));//*scale);
}