Added source code

utils/sector.scad

@@ -0,0 +1,36 @@
+//
+// NopSCADlib Copyright Chris Palmer 2018
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+//! A sector of a circle between two angles.
+//
+include <../core.scad>
+
+module sector(r, start_angle, end_angle) { //! Create specified sector given radius ```r```, ```start_angle``` and ```end_angle```
+    R = r * sqrt(2) + 1;
+
+    if(end_angle > start_angle)
+        intersection() {
+            circle4n(r);
+
+            // A 4 triangle fan
+            polygon([[0, 0],
+                     for(i = [0 : 4], a = start_angle + i * (end_angle - start_angle) / 4) R * [cos(a), sin(a)] ]);
+        }
+}