X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=reprap-play.git;a=blobdiff_plain;f=lemon-stand.scad.pl;h=8c1d10f54338529a21998c8656a3db2ba2fdaa25;hp=84417f2377b54ea4fa1f3a8de058aaaddbb6e60b;hb=62702e323fdd511901a9f37b367e4647f7c3f76e;hpb=287cc98bc3375dd3f3b72af14e3061f8aafca011

diff --git a/lemon-stand.scad.pl b/lemon-stand.scad.pl
index 84417f2..8c1d10f 100755
--- a/lemon-stand.scad.pl
+++ b/lemon-stand.scad.pl
@@ -7,16 +7,26 @@ use IO::File;
 use Data::Dumper;
 use constant tau => pi*2;
 
+my $ellipse = 25 / 2;
+my $circle = 7 / 2;
+my $channelh = 3;
+my $channelw = 4;
+my $xscale = 35 / 25;
+my $N = 180; # around ellipse
+my $M = 80; # around each circle
+my @channeldistprops = (0, 1/3, 2/3);
+
+my $NMdiv = $ENV{'LEMONSTAND_COARSE'} || 1;
+
+$M /= $NMdiv;
+$N /= $NMdiv;
+
 print <<END;
 // -*- C -*-
 // *** AUTOGENERATED - DO NOT EDIT ***
 END
 
-my $ellipse = 20;
-my $circle = 6;
-my $xscale = 2;
-my $N = 30; # around ellipse
-my $M = 20; # around each circle
+print "torusyup = ", ($circle / sqrt(2)), ";\n";
 
 our @ellipse = map {
     my $theta = tau * $_ / $N;
@@ -42,6 +52,11 @@ our @circles = map {
     } 0..($M-1) ];
 } 0..($N-1);
 
+sub scadvec ($) {
+    my ($v) = @_;
+    return "[ ".(join ", ", @$v)." ]"
+}
+
 sub torusy () {
     print "module Torusy(){ polyhedron(points=[";
     my $ptix = 0;
@@ -50,7 +65,7 @@ sub torusy () {
 	foreach my $j (0..$M-1) {
 	    print "," if $ptix;
 	    print "\n";
-	    print "    [ ", (join ", ", @{ $circles[$i][$j] }), " ]";
+	    print "    ",(scadvec $circles[$i][$j]);
 	    $cirpt[$i][$j] = $ptix++;
 	}
     }
@@ -80,10 +95,70 @@ sub torusy () {
 
 torusy();
 
+
+our @distances;
+push @distances, 0;
+foreach my $i (1..$N) {
+    my $dist = $distances[ $i-1 ];
+    $dist += abs($ellipse[$i % $N] - $ellipse[$i-1]);
+    $distances[$i] = $dist;
+}
+
+sub infodistprop ($) {
+    my ($distprop) = @_;
+    # returns
+    #   ( $ellipse_centreline_point,
+    #     $along_vector )
+    my $dist = $distprop * $distances[$N];
+    foreach my $i (0..$N-1) {
+	my $prorata =
+	    ($dist - $distances[$i]) /
+	    ($distances[$i+1] - $distances[$i]);
+	next unless 0 <= $prorata && $prorata <= 1;
+	print "// infodistprop $distprop => #$i=$ellipse[$i] $prorata $ellipse[$i+1]\n";
+	return (
+		(1-$prorata) * $ellipse[$i] + ($prorata) * $ellipse[$i+1],
+		$alongs[$i],
+	       );
+    }
+    die "$distprop ?";
+}
+
+sub channels(){
+    print "module Channels(){\n";
+    
+    foreach my $cdp (
+		     (map { 0.5 *  $_    } @channeldistprops),
+		     (map { 0.5 * ($_+1) } @channeldistprops),
+		    ) {
+	my ($ctr, $along) = infodistprop($cdp);
+	my $angle = atan2(-$along->[0], $along->[1]);
+	print "  translate(",scadvec($ctr),")\n";
+	print "  rotate([0,0,$angle*360/",tau,"])\n";
+	print "  rotate([0,90,0])\n";
+	print "  translate([0,0, -2*$circle])\n";
+	print "  scale([1, $channelw/$channelh/2, 1])\n";
+	print "  rotate([0,0,360/8/2])\n";
+	print "  cylinder(r=$channelh, h=4*$circle, \$fn=8);\n";
+    }
+    print "}\n";
+}
+
+channels();
+
 while (<DATA>) { print };
 
 STDOUT->error and die $!;
 STDOUT->flush or die $!;
 
 __DATA__
-Torusy();
+module Stand(){
+    difference(){
+	translate([0,0,torusyup])
+	    Torusy();
+	Channels();
+	translate([-200,-200,-50])
+	    cube([400,400,50]);
+    }
+}
+Stand();