var rad_ang = 15 * 4.848e-6; // 15 arcsec rad

var rad_act;

var alt = 100; // lgs alt [m]

var sc = 10;

var slider1;

var slider2;

const altmin = 90;

const altmax = 230;

​

function setup() {

  createCanvas(400, 400, WEBGL);

  createP("Altitude:");

  slider1 = createSlider(altmin, altmax, 100);

  createP("Precision:");

  slider2 = createSlider(1, 5, 2.0, 0.01);

  background(255);

}

​

function draw() {

  alt = slider1.value();

  var prec = slider2.value()

  rad_act = alt * rad_ang * 1000;

  rotateX(PI / 2-0.2);

  rotateZ(0.5);

  rotateY(-(alt - altmin) / (altmax - altmin) * TWO_PI / NLGS * prec);

  translate(0,150-alt,0);

  background(255);

  fill(200);

  stroke(10);

  cylinder(1000 * sc * altmax * rad_ang * 1.1 / 2, 10, 20, 1);

  fill(255);

  push();

  rotateY((alt - altmin) / (altmax - altmin) * TWO_PI / NLGS * prec);

  translate(0,-500+alt,0);

  cylinder(10, 1000, 20, 1);

  pop();

  fill(0);

  noStroke();

  var i,j;

  for (j = 0; j < 100; j++) {

    var alt_tmp = j/100*(altmax-altmin)+altmin;

    var rad_tmp = alt_tmp * rad_ang * 1000;

    for (i = 0; i < NLGS; i++) {

      push();

      rotateY((alt_tmp - altmin) / (altmax - altmin) * TWO_PI / NLGS * prec);

      translate(rad_tmp * cos(i * TWO_PI / 8) * sc / 2, 0, rad_tmp * sin(i * TWO_PI / 8) * sc / 2);

      //stroke(10);

      cylinder(3, 10.1,8,1);

      pop();

    }

  }

  fill(255, 255, 0);

  for (i = 0; i < NLGS; i++) {

    push();

    rotateY((alt - altmin) / (altmax - altmin) * TWO_PI / NLGS  * prec);

    translate(rad_act * cos(i * TWO_PI / 8) * sc / 2, 0, rad_act * sin(i * TWO_PI / 8) * sc / 2);

    cylinder(5, 11);

    pop();

  }

}