// -*- C -*-

$hinge_pin_dia = 0.795 + 0.35;
$hinge_main_dia = 4.0;
$hinge_inter_gap = 0.50;
$hinge_prong_minwidth = 3.5;
$hinge_noncrit_gap = 1.0;

$fa = 3;
$fs = 0.05;

module HingePinPlan(){
  circle(r= $hinge_pin_dia/2);
}

module HingeProngPlan(behind){
  hull(){
    circle(r= $hinge_main_dia/2);
    polygon([[0,0],
	     [-$hinge_main_dia/2, -behind],
	     [+$hinge_main_dia/2, -behind]]);
  }
}

module HingeGapPlan() {
  circle(r = $hinge_main_dia/2 + $hinge_inter_gap);
}

module PlanDemo(){
  HingeProngPlan(5);
  %HingeGapPlan();
  translate([0,0,1]) color("red") HingePinPlan();
}

module HingePositive(l){
  linetr_x_yz(0, l)
    HingeProngPlan();
}  

module HingeNegative(l){
  eff_l = l + $hionge_inter_gap;
  pairs = floor(eff_l / (2*($hinge_prong_minwidth + $hinge_inter_gap)));
  stride = eff_l / pairs;
  prong_width = stride/2 - $hinge_inter_gap;
  linextr_x_ayz(-0.1, l+0.1)
    HingePinPlan();
  for (i=[0:pairs-1]) {
    translate(stride * i * [1,0,0])
      linextr_x_yz(0, prong_width + $hinge_inter_gap)
      HingeGapPlan();
  }
}

PlanDemo();