place charges randomly

sketch.js

@@ -18,6 +18,42 @@ function draw() {
 
   make_lights();
   draw_sphere(sphere_radius, 25);
+  draw_charges(sphere_radius);
+}
+
+function make_charges(n) {
+  charges.clear();
+  for (let i = 0; i < n; i += 1) {
+    let position;
+    if (i == 0) {
+      position = createVector(0, -1, 0);
+    } else {
+      const lat = random(-TAU / 4, TAU / 4);
+      const lon = random(0, TAU);
+      position = createVector(
+        cos(lat) * cos(lon),
+        sin(lat),
+        cos(lat) * sin(lon),
+      );
+    }
+    charges.set(counter, position);
+    counter += 1;
+  }
+}
+
+function draw_charges(radius) {
+  push();
+  noStroke();
+  ambientMaterial(0xbf, 0x00, 0x00);
+  for (let charge of charges.values()) {
+    let position = charge.copy();
+    position.mult(radius);
+    push();
+    translate(position.x, position.y, position.z);
+    sphere(15);
+    pop();
+  }
+  pop();
 }
 
 function draw_sphere(radius, n_axis_circles) {
@@ -86,5 +122,7 @@ function make_lights() {
 function keyPressed() {
   if (key == 'd') {
     sphere_mode = sphere_mode === 'earth' ? 'circles' : 'earth';
+  } else if (key >= '0' && key <= '9') {
+    make_charges(int(key));
   }
 }