add sphere_maze

examples/maze/sphere_maze.scad

@@ -0,0 +1,38 @@
+use <hull_polyline3d.scad>;
+use <rotate_p.scad>;
+use <square_maze.scad>;
+use <matrix/m_rotation.scad>;
+use <experimental/pt_to_sphere.scad>;
+
+r = 10;
+rows = 24;
+columns = 18;
+block_width = 1;
+wall_thickness = .5;   
+pole_offset = block_width * 1.5;
+
+module sphere_maze() {
+    size = [rows * block_width, columns * block_width + pole_offset * 2];
+    blocks = go_maze( 
+        1, 1,   // starting point
+        starting_maze(rows, columns),  
+        rows, columns, y_circular = true
+    );
+
+    p_offset = [wall_thickness * columns, pole_offset, 0];
+    mr = m_rotation(90);
+
+    walls = maze_walls(blocks, rows, columns, block_width, bottom_border = false);
+    for(wall_pts = walls) {  
+        rxpts = [
+            for(p = wall_pts) 
+                pt_to_sphere(mr * [p[0], p[1], 0, 0] + p_offset, size, r)
+        ];
+        hull_polyline3d(rxpts, wall_thickness, $fn = 6);
+    }
+}
+
+sphere_maze();
+color("black") 
+rotate([0, 90, 0]) 
+    sphere(r);