// Author Reva - 2020-02-21

float plot(float r, float pct){
	return  smoothstep( pct-0.2, pct, r) -smoothstep( pct, pct+0.2, r);
}

vec3 pal( in float t, in vec3 a, in vec3 b, in vec3 c, in vec3 d ){
        return a + b*cos( 6.28318*(c*t+d) );
}


void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = fragCoord/iResolution.xy;
    vec3 col = vec3(1.0);
    vec2 pos = vec2(0.5) - uv;
    pos.x *= iResolution.x/iResolution.y;
    pos *= cos(iTime)*1.0+1.5;

    float r = length(pos)*2.0;
    float a = atan(pos.y,pos.x);

    float f = abs(cos(a*2.5+iTime*0.5))*sin(iTime*2.0)*0.698+cos(iTime)-4.0;
    float d = f-r;
    
    col = (vec3(smoothstep(fract(d),fract(d)+-0.200,0.160))-vec3(smoothstep(fract(d),fract(d)+-1.184,0.160)) ) 
	* pal( f, vec3(0.725,0.475,0.440),vec3(0.605,0.587,0.007),vec3(1.0,1.0,1.0),vec3(0.310,0.410,0.154) );
    float pct = plot(r*0.272,fract(d*(sin(iTime)*0.45+0.5)));
	
    col += pct*pal( r, vec3(0.750,0.360,0.352),vec3(0.450,0.372,0.271),vec3(0.540,0.442,0.264),vec3(0.038,0.350,0.107) );

    // Output to screen
    fragColor = vec4(col,pct*0.3);
}