sphere

sketch.js

@@ -0,0 +1,66 @@
+let charges = new Map();
+let counter = 0;
+
+function setup() {
+  createCanvas(600, 600, WEBGL);
+}
+
+function draw() {
+  orbitControl();
+  background(50);
+
+  make_lights();
+  draw_sphere(200, 25);
+}
+
+function draw_sphere(radius, n_axis_circles) {
+  stroke(0x3f);
+  noFill();
+
+  push();
+  rotateX(TAU / 4);
+  draw_circles(
+    radius,
+    n_axis_circles,
+    color(0x00, 0x9f, 0xff),
+    color(0xff, 0x9f, 0x00),
+  );
+  pop();
+  push();
+  rotateY(TAU / 4);
+  draw_circles(
+    radius,
+    n_axis_circles,
+    color(0xff, 0x00, 0xff),
+    color(0x00, 0xff, 0x00),
+  );
+  pop();
+}
+
+function draw_circles(radius, n_circles, pole_1_color, pole_2_color) {
+  push();
+  stroke(pole_1_color);
+  translate(0, 0, -radius);
+  point(0, 0);
+  pop();
+  for (let i = 1; i < n_circles; i += 1) {
+    const angle = map(i, 0, n_circles - 1, -TAU / 4, TAU / 4);
+    const circle_radius = radius * cos(angle);
+    push();
+    translate(0, 0, radius * sin(angle));
+    circle(0, 0, circle_radius * 2);
+    pop();
+  }
+  push();
+  stroke(pole_2_color);
+  translate(0, 0, radius);
+  point(0, 0);
+  pop();
+}
+
+function make_lights() {
+  let light = createVector(0, 1, -1);
+  light.normalize();
+  directionalLight(0x1f, 0x1f, 0x1f, light);
+  ambientLight(0xbf);
+}