X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=distort-stl;fp=distort-stl;h=dd430c9e452663b9aafcabdd7dc0abc3dfaf5ae7;hb=45146328f74d660232d33b0867ae1f6cd700e034;hp=0eb71fd6179121f346c1d60e4c52e89ba82d1528;hpb=f79993b675194a1e13713da23cf27642d2a381e4;p=reprap-play.git

diff --git a/distort-stl b/distort-stl
index 0eb71fd..dd430c9 100755
--- a/distort-stl
+++ b/distort-stl
@@ -44,27 +44,37 @@ sub shift_arg () {
 
 #no warnings qw(recursion);
 
-sub subdivide_triangle ($$) {
-    my ($t, $fn) = @_;
-
-    #print STDERR 'SUBDIV', Dumper($t, $fn);
-
-    my @mids;
+sub maybe_subdivide_triangle ($$$$) {
+    my ($t, $ok, $changed, $edge_need_subdivide_fn) = @_;
+    
     foreach my $ix (0..2) {
 	my $jx = ($ix+1) % 3;
-	my @midp;
-	foreach my $ci (0..2) {
-	    push @midp, 0.5 * ($t->[$ix][$ci] + $t->[$jx][$ci]);
+	my $kx = ($ix+2) % 3;
+	if ($edge_need_subdivide_fn->($t[$ix], $t[$jx])) {
+	    foreach my $ci (0..2) {
+		push @midp, 0.5 * ($t->[$ix][$ci] + $t->[$jx][$ci]);
+	    }
+	    # triangle i-j-k, splitting edge i-m
+	    # gives    i-m-k, k-m-j
+	    push @$changed,
+		[ $t[$ix], \@midp, $t[kx] ],
+		[ $t[$kx], \@midp, $t[jx] ];
+	    return;
 	}
-	push @mids, \@midp;
     }
-    foreach my $ix (0..2) {
-	#print STDERR 'SUBDIV IX ', $ix, "\n";
-	my $kx = ($ix+2) % 3;
-	$fn->([ $t->[$ix], $mids[$ix], $mids[$kx] ]);
+    push @$ok, $t;
+}
+
+sub maybe_subdivide ($) {
+    my ($edge_need_subdivide_fn) = @_;
+    
+    my @small_enough = ();
+    while (my $t = shift @$triangles) {
+	maybe_subdivide_triangle $t, \@small_enough, $triangles,
+	    $edge_need_subdivide_fn;
     }
-    #print STDERR 'SUBDIV MID\n';
-    $fn->(\@mids);
+
+    $triangles = \@small_enough;
 }
 
 sub append_triangle ($) {
@@ -83,17 +93,9 @@ sub op__set_fa () {
 our $project_cylinder_radius;
 our $project_cylinder_max_d_theta;
 
-sub project_cylinder_triangle_need_subdivide ($) {
-    my ($t) = @_;
-    my @thetas = map { $_->[0] / $project_cylinder_radius } @$t;
-
-    foreach my $ix (0..2) {
-	if (abs($thetas[$ix] - $thetas[($ix+1)%3])
-	    > $project_cylinder_max_d_theta) {
-	    return 1;
-	}
-    }
-    return 0;
+sub project_cylinder_edge_need_subdivide ($$) {
+    my @thetas = map { $_->[0] / $project_cylinder_radius } @_;
+    return abs($thetas[0] - $thetas[1]) > $project_cylinder_max_d_theta;
 }
 
 sub project_cylinder_tri {
@@ -119,18 +121,8 @@ sub op__project_cylinder () {
     $project_cylinder_radius = shift_arg;
     $project_cylinder_max_d_theta = $fa * TAU/360;
 
-    my @small_enough = ();
-    while (my $t = shift @$triangles) {
-	if (!project_cylinder_triangle_need_subdivide $t) {
-	    push @small_enough, $t;
-	} else {
-	    local $output = $triangles;
-	    subdivide_triangle $t, \&append_triangle;
-	}
-    }
-
-    $triangles = \@small_enough;
-
+    maybe_subdivide \&project_cylinder_triangle_need_subdivide;
+    
     $output = [];
     foreach my $t (@$triangles) {
 	project_cylinder_tri $t;