From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 25 Nov 2018 13:30:15 +0000 (+0000)
Subject: distort-stl: new approach: split longest edge (does not work yet)
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=reprap-play.git;a=commitdiff_plain;h=f5e5bb227ce24bc8faa92c700583f7a06bc894d0;ds=sidebyside

distort-stl: new approach: split longest edge (does not work yet)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/distort-stl b/distort-stl
index 9d85690..8167e35 100755
--- a/distort-stl
+++ b/distort-stl
@@ -85,44 +85,57 @@ sub maybe_subdivide_triangle ($$$$) {
     my ($t, $ok, $changed, $edge_need_subdivide_fn) = @_;
 
     print STDERR sprintf_triangle $t if $debug;
-    
+
+    my (@longest) = qw(-1);
+
     foreach my $ix (0..2) {
 	my $jx = ($ix+1) % 3;
-	my $kx = ($ix+2) % 3;
-	if ($edge_need_subdivide_fn->($t->[$ix], $t->[$jx])) {
-	    printf STDERR
-		" S i=%d j=%d k=%d ",
-		$ix, $jx, $kx
-		if $debug;
-	    my @midp;
-	    foreach my $ci (0..2) {
-		push @midp, 0.5 * ($t->[$ix][$ci] + $t->[$jx][$ci]);
-	    }
-
-	    printf STDERR
-		" midp %11.6f,%11.6f,%11.6f\n",
-		@midp
-		if $debug;
-
-	    # triangle i-j-k, splitting edge i-m
-	    # gives    i-m-k, k-m-j
-	    my $gensplit = sub {
-		my ($ixjx, $xwhat) = @_;
-		my $n = [ @$t ];
-		$n->[$ixjx] = \@midp;
-		$n->[3] = "$t->[3]$xwhat";
-		printf STDERR "%s\n", sprintf_triangle $n if $debug;
-		unshift @$changed, $n;
-	    };
-	    $gensplit->($ix, "a$ix$jx");
-	    $gensplit->($jx, "b$ix$jx");
-	    return;
+	next unless $edge_need_subdivide_fn->($t->[$ix], $t->[$jx]);
+	my $l2 = 0;
+	foreach my $ci (0..2) {
+	    my $d = $t->[$ix][$ci] - $t->[$jx][$ci];
+	    $l2 += $d*$d;
 	}
+	next unless $l2 > $longest[0];
+	@longest = ($l2, $ix, $jx);
     }
-    push @$ok, $t;
-    printf STDERR "OK nok=%d nchanged=%d\n",
-	(scalar @$ok), (scalar @$changed)
+    if ($longest[0] < 0) {
+	push @$ok, $t;
+	printf STDERR "OK nok=%d nchanged=%d\n",
+	    (scalar @$ok), (scalar @$changed)
+	    if $debug;
+	return;
+    }
+    my ($dummy,$ix,$jx) = @longest;
+    my $kx = ($ix+2) % 3;
+
+    printf STDERR
+	" S i=%d j=%d k=%d ",
+	$ix, $jx, $kx
 	if $debug;
+    my @midp;
+    foreach my $ci (0..2) {
+	push @midp, 0.5 * ($t->[$ix][$ci] + $t->[$jx][$ci]);
+    }
+
+    printf STDERR
+	" midp %11.6f,%11.6f,%11.6f\n",
+	@midp
+	if $debug;
+
+    # triangle i-j-k, splitting edge i-m
+    # gives    i-m-k, k-m-j
+    my $gensplit = sub {
+	my ($ixjx, $xwhat) = @_;
+	my $n = [ @$t ];
+	$n->[$ixjx] = \@midp;
+	$n->[3] = "$t->[3]$xwhat";
+	printf STDERR "%s\n", sprintf_triangle $n if $debug;
+	unshift @$changed, $n;
+    };
+    $gensplit->($ix, "a$ix$jx");
+    $gensplit->($jx, "b$ix$jx");
+    return;
 }
 
 sub maybe_subdivide ($) {