add rand_pts_sphere

src/experimental/rand_pts_sphere.scad

@@ -0,0 +1,39 @@
+use <util/degrees.scad>;
+
+function rand_pts_sphere(radius, value_count, seed = undef) =
+    let(r_nums = is_undef(seed) ? rands(0, 1, value_count * 2) :  rands(0, 1, value_count * 2, seed))
+	[
+		for(i = [0:value_count - 1])
+		let(
+			theta = degrees(2 * PI * r_nums[i]),
+			phi = acos(r_nums[i + value_count] * 2 - 1),
+			sin_phi = sin(phi),
+			x = sin_phi * cos(theta),
+			y = sin_phi * sin(theta),
+			z = cos(phi)
+		)
+		[x, y, z]
+	] * radius;
+
+/*
+
+use <experimental/rand_pts_sphere.scad>;
+use <polyhedron_hull.scad>;
+
+number = 20;
+u = rands(0, 1, number);
+v = rands(0, 1, number);
+radius = 2;
+
+points = rand_pts_sphere(radius, number);
+
+polyhedron_hull(points);
+
+for(p = points) {
+    translate(p)
+	    sphere(.05);
+}
+
+%sphere(radius, $fn = 48);
+
+*/