From 95ad6e5155db8fd0095363df67e6eb525099eef0 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 25 Nov 2018 13:17:45 +0000
Subject: [PATCH] distort-stl: debugging, make STDERR output conditional

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 distort-stl | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/distort-stl b/distort-stl
index a470ae3..cc959dd 100755
--- a/distort-stl
+++ b/distort-stl
@@ -32,6 +32,8 @@ use Data::Dumper;
 
 sub TAU () { M_PI * 2; }
 
+our $debug = $ENV{DISTORT_DEBUG};
+
 my $ps = $ENV{DISTORT_PS};
 if ($ps) {
     open PS, "> $ps" or die $!;
@@ -53,6 +55,8 @@ sub shift_arg () {
 sub sprintf_triangle ($) {
     my ($t) = @_;
 
+    return '' unless $debug;
+
     if ($ps && $t->[3] =~ m/$ENV{DISTORT_PS_RE}/) {
 	printf PS <<'END',
  %20.16g %20.16g %20.16g moveto
@@ -80,7 +84,7 @@ END
 sub maybe_subdivide_triangle ($$$$) {
     my ($t, $ok, $changed, $edge_need_subdivide_fn) = @_;
 
-    print STDERR sprintf_triangle $t;
+    print STDERR sprintf_triangle $t if $debug;
     
     foreach my $ix (0..2) {
 	my $jx = ($ix+1) % 3;
@@ -88,7 +92,8 @@ sub maybe_subdivide_triangle ($$$$) {
 	if ($edge_need_subdivide_fn->($t->[$ix], $t->[$jx])) {
 	    printf STDERR
 		" S i=%d j=%d k=%d ",
-		$ix, $jx, $kx;
+		$ix, $jx, $kx
+		if $debug;
 	    my @midp;
 	    foreach my $ci (0..2) {
 		push @midp, 0.5 * ($t->[$ix][$ci] + $t->[$jx][$ci]);
@@ -96,26 +101,28 @@ sub maybe_subdivide_triangle ($$$$) {
 
 	    printf STDERR
 		" midp %11.6f,%11.6f,%11.6f\n",
-		@midp;
+		@midp
+		if $debug;
 
 	    # triangle i-j-k, splitting edge i-m
 	    # gives    i-m-k, k-m-j
 	    my $n = [ @$t ]; $n->[$ix] = \@midp;  $n->[3] = "$t->[3]a$ix$jx";
 	    unshift @$changed, $n;
 
-	    printf STDERR "%s\n", sprintf_triangle $n;
+	    printf STDERR "%s\n", sprintf_triangle $n if $debug;
 
 	    my $n = [ @$t ]; $n->[$jx] = \@midp;  $n->[3] = "$t->[3]b$ix$jx";
 	    unshift @$changed, $n;
 
-	    printf STDERR "%s\n", sprintf_triangle $n;
+	    printf STDERR "%s\n", sprintf_triangle $n if $debug;
 
 	    return;
 	}
     }
     push @$ok, $t;
     printf STDERR "OK nok=%d nchanged=%d\n",
-	(scalar @$ok), (scalar @$changed);
+	(scalar @$ok), (scalar @$changed)
+	if $debug;
 }
 
 sub maybe_subdivide ($) {
-- 
2.30.2