From 5ebf3e18e4a87a820428653c80e05d64da98815a Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Sun, 14 May 2017 12:50:52 +0800
Subject: [PATCH] refactored

---
 src/__private__/__half_trapezium.scad | 31 +++++++++++++++++
 src/rounded_cylinder.scad             | 48 ++++++++-------------------
 2 files changed, 44 insertions(+), 35 deletions(-)
 create mode 100644 src/__private__/__half_trapezium.scad

diff --git a/src/__private__/__half_trapezium.scad b/src/__private__/__half_trapezium.scad
new file mode 100644
index 00000000..28c352c0
--- /dev/null
+++ b/src/__private__/__half_trapezium.scad
@@ -0,0 +1,31 @@
+function __half_trapezium(radius, h, round_r) =
+    let(
+        is_vt = __is_vector(radius),
+        r1 = is_vt ? radius[0] : radiusm,
+        r2 = is_vt ? radius[1] : radius,
+        frags = __frags(round_r),
+        b_ang = atan2(h, r1 - r2),
+        b_sector_angle = 180 - b_ang,
+        b_leng = r1 - round_r / tan(b_ang / 2),
+        b_round_frags = frags * b_sector_angle / 360,
+        b_end_angle = -90 + b_sector_angle,
+        t_sector_angle = b_ang,
+        t_leng = r2 - round_r * tan(t_sector_angle / 2),
+        t_round_frags = frags * t_sector_angle / 360,
+        
+        half_h = h / 2,
+        
+        br_corner = [
+            for(pt = __pie_for_rounding(round_r, -90, b_end_angle, b_round_frags))
+                [pt[0] + b_leng, pt[1] + round_r - half_h]
+        ],
+
+        tr_corner = [
+            for(pt = __pie_for_rounding(round_r, 90 - t_sector_angle, 90, t_round_frags))
+                [pt[0] + t_leng, pt[1] + h - round_r - half_h]
+        ]
+    )    
+    concat(
+        br_corner,
+        tr_corner
+    );
\ No newline at end of file
diff --git a/src/rounded_cylinder.scad b/src/rounded_cylinder.scad
index 6f5567cf..fc74f7d6 100644
--- a/src/rounded_cylinder.scad
+++ b/src/rounded_cylinder.scad
@@ -13,41 +13,19 @@
 include <__private__/__is_vector.scad>;
 include <__private__/__frags.scad>;
 include <__private__/__pie_for_rounding.scad>;
+include <__private__/__half_trapezium.scad>;
 
-module rounded_cylinder(radius, h, round_r, convexity = 2, center = false) {
-    is_vt = __is_vector(radius);
-    r1 = is_vt ? radius[0] : radius;
-    r2 = is_vt ? radius[1] : radius;
+module rounded_cylinder(radius, h, round_r, convexity = 2, center = false) {  
+    r_corners = __half_trapezium(radius, h, round_r);
 
-    function round_frags(sector_angle) = __frags(round_r) * sector_angle / 360;
-
-    b_ang = atan2(h, r1 - r2);
-    b_sector_angle = 180 - b_ang;
-    b_leng = r1 - round_r / tan(b_ang / 2);
-    b_round_frags = round_frags(b_sector_angle);
-    b_end_angle = -90 + b_sector_angle;
-    
-    t_sector_angle = b_ang;
-    t_leng = r2 - round_r * tan(t_sector_angle / 2);
-    t_round_frags = round_frags(t_sector_angle);
-    
-    b_corner = [
-        for(pt = __pie_for_rounding(round_r, -90, b_end_angle, b_round_frags))
-            [pt[0] + b_leng, pt[1] + round_r]
-    ];
-
-    t_corner = [
-        for(pt = __pie_for_rounding(round_r, 90 - t_sector_angle, 90, t_round_frags))
-            [pt[0] + t_leng, pt[1] + h - round_r]
-    ];
-
-    translate(center ? [0, 0, -h/2] : [0, 0, 0]) rotate(180) rotate_extrude(convexity = convexity) 
-        polygon(
-            concat(
-                [[0, 0], [b_leng, 0]],
-                b_corner,
-                t_corner,            
-                [[t_leng, h], [0, h]]
-            )
-        );
+    translate(center ? [0, 0, 0] : [0, 0, h/2]) 
+        rotate(180) 
+            rotate_extrude(convexity = convexity) 
+                polygon(
+                    concat(
+                        [[0, -h/2]],
+                        r_corners,           
+                        [[0, h/2]]
+                    )
+                );
 }
\ No newline at end of file