add experimental/pt_to_sphere

src/experimental/pt_to_sphere.scad

@@ -0,0 +1,16 @@
+use <rotate_p.scad>;
+
+function pt_to_sphere(p, size, r, angle = [180, 360]) =
+    let(
+        x = p[0],
+        y = p[1],
+        za = angle[0],
+        xa = angle[1],
+        xlen = size[0],
+        ylen = size[1],
+        za_step = za / ylen,
+        rza = za_step * y,
+        rzpt = [r * cos(rza), r * sin(rza), 0],
+        rxpt = rotate_p(rzpt, [xa / xlen * x, 0, 0])
+    )
+    rxpt;