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 9d8569062b193e10413a3c91e643feeed4f633b9..8167e3540932a14f62954b1790e229528ba624ec 100755 (executable)
--- 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 ($) {