add isosphere

src/experimental/isosphere.scad

@@ -0,0 +1,35 @@
+use <experimental/tri_subdivide.scad>;
+
+module isosphere(radius, detail = 0) {
+    function prj2sphere(t) = [for(p = t) p / norm(p) * radius];
+
+    // Icosahedron
+    t = (1 + sqrt(5)) / 2 ;
+
+	icosahedron_points = [
+		[- 1, t, 0],  [1, t, 0],  [- 1, - t, 0], [1, - t, 0],
+		[0, - 1, t],  [0, 1, t],  [0, - 1, - t], [0, 1, - t],
+		[t, 0, - 1],  [t, 0, 1],  [- t, 0, - 1],  [- t, 0, 1]
+	];
+
+	icosahedron_faces = [
+	    [5, 11, 0], [1, 5, 0], [7, 1, 0], [10, 7, 0], [11, 10, 0], 
+		[9, 5, 1], [4, 11, 5], [2, 10, 11], [6, 7, 10], [8, 1, 7], 
+		[4, 9, 3], [2, 4, 3], [6, 2, 3], [8, 6, 3], [9, 8, 3], 
+		[5, 9, 4], [11, 4, 2], [10, 2, 6], [7, 6, 8], [1, 8, 9]
+	];
+	
+	tris = [
+	    for(face = icosahedron_faces)
+		[for(i = face) icosahedron_points[i]]
+	];
+	
+	points = detail == 0 ? [for(tri = tris) each prj2sphere(tri)] : [
+	    for(tri = tris)
+		each [for(t = tri_subdivide(tri, detail)) each prj2sphere(t)]
+	];
+	
+	faces = [for(i = [0:3:len(points) - 3]) [i, i + 1, i + 2]];
+
+    polyhedron(points, faces);
+}