add rands_sphere, rands_disk

test/util/rands_disk.scad

@@ -0,0 +1,25 @@
+function rands_disk(radius, value_count, seed = undef) =
+    let(
+	    seed_undef = is_undef(seed),
+	    theta = seed_undef ? rands(0, 360, value_count * 2) :  rands(0, 360, value_count * 2, seed),
+		k = seed_undef ? rands(0, 1, value_count * 2) : rands(0, 1, value_count * 2, seed)
+		
+	)
+	[
+	    for(i = [0:value_count - 1])
+		let(r = sqrt(k[i]) * radius)
+		[cos(theta[i]), sin(theta[i])] * r
+	];
+	
+/*
+number = 10000;
+radius = 2;
+
+points = rand_pts_circle(radius, number);
+
+for(p = points) {
+    translate(p)
+	    circle(.01);
+}
+
+%circle(radius, $fn = 96);*/

test/util/rands_sphere.scad

@@ -0,0 +1,37 @@
+use <util/degrees.scad>;
+
+function rands_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;
+radius = 2;
+
+points = rand_pts_sphere(radius, number);
+
+polyhedron_hull(points);
+
+for(p = points) {
+    translate(p)
+	    sphere(.05);
+}
+
+%sphere(radius, $fn = 48);
+
+*/