added golden_spiral_extrude.scad

src/golden_spiral_extrude.scad

@@ -0,0 +1,37 @@
+/**
+* golden_spiral_extrude.scad
+*
+* Extrudes a 2D shape along the path of a golden spiral.
+*
+* @copyright Justin Lin, 2017
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib-golden_spiral_extrude.html
+*
+**/
+
+module golden_spiral_extrude(shape_pts, from, to, point_distance, 
+                             rt_dir = "CT_CLK", twist = 0, scale = 1.0) {
+
+    pts_angles = golden_spiral(
+        from = from, 
+        to = to, 
+        point_distance = point_distance,
+        rt_dir = rt_dir
+    );
+
+    pts = [for(pt_angle = pts_angles) pt_angle[0]];
+    angles = [
+        for(i = [0:len(pts_angles) - 1]) 
+            [90, 0, pts_angles[i][1] + (rt_dir == "CT_CLK" ? 0 : 90)]
+    ];
+
+    polysections(
+        cross_sections(
+            shape_pts, 
+            pts, angles, 
+            twist = twist, 
+            scale = scale
+        )
+    );
+}