From 3851c067c96a87753e3abafc1a4d2724f989135d Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Wed, 16 Sep 2020 00:04:08 +0100
Subject: [PATCH] pin-hinge: wip

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 pin-hinge.scad | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/pin-hinge.scad b/pin-hinge.scad
index c17ce81..4eba185 100644
--- a/pin-hinge.scad
+++ b/pin-hinge.scad
@@ -34,21 +34,30 @@ module PlanDemo(){
   translate([0,0,1]) color("red") HingePinPlan();
 }
 
-module HingePositive(l, behind){
-  linextr_x_yz(0, l)
-    HingeProngPlan(behind);
-}  
-
-module HingeNegative(l){
+module HingePinUnitCell(l) {
   eff_l = l + $hinge_inter_gap;
   pairs = floor(eff_l / (2*($hinge_prong_minwidth + $hinge_inter_gap)));
   stride = eff_l / pairs;
-  prong_width = stride/2 - $hinge_inter_gap;
-  linextr_x_yz(-0.1, l+0.1)
-    HingePinPlan();
+  $hinge__prong_width = stride/2 - $hinge_inter_gap;
   for (i=[0:pairs-1]) {
     translate(stride * i * [1,0,0])
-      linextr_x_yz(0 + (i==0 ? -0.1 : 0), prong_width + $hinge_inter_gap)
+      children(0);
+  }
+}
+
+module HingePositive(l, behind){
+  HingePinUnitCell(l){
+    linextr_x_yz(0, $hinge__prong_width)
+      HingeProngPlan(behind);
+  }
+}
+
+module HingeNegative(l){
+  linextr_x_yz(-0.1, l+0.1)
+    HingePinPlan();
+  HingePinUnitCell(l){
+    linextr_x_yz($hinge__prong_width,
+		 $hinge__prong_width*2 + 2*$hinge_inter_gap)
       HingeGapPlan();
   }
 }
-- 
2.30.2