#version 330
// #pragma optionNV (unroll 1)

#define show_vec

#define SEG 32

#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 R) {
	float dr = 2. * PI / float(SEG);
	vec3 sum = vec3(0);
	for (int i = 0; i < SEG; i++){
		float theta = dr * float(i);
		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 () {
	float R = 0.8;
	float R2 = abs(sin((time+8.2)/.6))+0.5;
	vec2 uv = UVo;
	vec2 poz = vec2(uv*2.);		// zavrteti moramo tako točke same, kot tudi
	vec2 offset = vec2(R/2.,0);	// njihove komponente
	float kot = time/.4;
	float multi = n*I/**abs(sin(time/.2)+0.2)*/;
	vec2 dodatek = vec2(sin(time/.6)*.5, cos(time/.4)*.6);
	vec3 rez =	tuljava(
				vec3(poz+offset, 1/2*R), R
			)*n*I +
			tuljava(
				vec3(
					vec2(poz-offset+dodatek)*
						mat2(	cos(kot),
							sin(kot),	-sin(kot),
									cos(kot)
						),
					1/2*R
				),
				R2
			)*multi*mat3(	cos(kot),
					sin(kot),
					0,
							-sin(kot),
							cos(kot),
							0,
									0,
									0,
									1);
	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.);
}
 */