#version 330
#pragma optionNV (unroll 1)

#define show_vec

#define SEG 32

#define R .8
#define I .5
#define n 100.

#define PI 3.1415

in vec2 UVo;

uniform float time;
uniform int OPTIONS;

out vec4 fragColor;

vec3 tuljava (vec3 pz) {
	float dr = 2. * PI / float(SEG);
	vec3 sum = vec3(0);
	for (int i = 0; i < SEG; i++){
		float theta = dr * float(i);
		// jebi se, zakaj neza? pisat ?ita linearno >:(
		vec3 dl = vec3(0,cos(theta),-sin(theta))*dr*R;
		vec3 r  = vec3(0,sin(theta),cos(theta))*R;
		r+=pz;
		sum+=cross(dl,r)/(length(r)*length(r)*length(r));
	}
	sum *= 1e-6;
	return sum;
}

void main () {
	vec2 uv = UVo;
	vec3 poz = vec3(uv*2.,sin(time/10.)*R);
	vec3 offset = vec3(R/2.,0,0);

	vec3 rez = tuljava(poz+offset)*n*I +
		tuljava(poz-offset)*n*I;
	rez *= 1000.;
#ifdef show_vec
	fragColor = vec4(rez, 1);
#else
	fragColor = vec4(vec3(length(rez)), 1);
#endif
}
/*
   uniform float time;
   uform int OPTIONS;
//uniform mat2 bounds;

out vec4 frag_colour;


void main() {
vec2 UV = UVo;
float scale = 1.1;
vec2 complex=UV*scale;
vec2 ot=vec2(0);
int tmpy=OPTIONS;
for (int x = 0; x < 16; x++){
ot=vec2(complex.x*ot.x-complex.y*ot.y,complex.x*ot.y+complex.y*ot.x);
int swch = tmpy & 1;
ot+=complex * (swch*2-1);
tmpy>>=1;
}

frag_colour = vec4(vec3(smoothstep(.05,0,length(ot))), 1.);
}
 */