2 files changed, 35 insertions, 3 deletions

diff --git a/lib/Slic3r/GUI/PreviewCanvas.pm b/lib/Slic3r/GUI/PreviewCanvas.pm
index 05d7828a4..c0638ddb6 100644
--- a/lib/Slic3r/GUI/PreviewCanvas.pm
+++ b/lib/Slic3r/GUI/PreviewCanvas.pm
@@ -8,7 +8,8 @@ use OpenGL qw(:glconstants :glfunctions :glufunctions);
 use base qw(Wx::GLCanvas Class::Accessor);
 use Math::Trig qw(asin);
 use List::Util qw(reduce min max first);
-use Slic3r::Geometry qw(X Y Z MIN MAX triangle_normal normalize deg2rad tan);
+use Slic3r::Geometry qw(X Y Z MIN MAX triangle_normal normalize deg2rad tan scale unscale);
+use Slic3r::Geometry::Clipper qw(offset_ex);
 use Wx::GLCanvas qw(:all);
  
 __PACKAGE__->mk_accessors( qw(quat dirty init mview_init
@@ -16,6 +17,7 @@ __PACKAGE__->mk_accessors( qw(quat dirty init mview_init
                               volumes initpos
                               sphi stheta
                               cutting_plane_z
+                              cut_lines_vertices
                               ) );
 
 use constant TRACKBALLSIZE => 0.8;
@@ -107,6 +109,7 @@ sub load_object {
         my $color = [ @{COLORS->[ $color_idx % scalar(@{&COLORS}) ]} ];
         push @$color, $volume->modifier ? 0.5 : 1;
         push @{$self->volumes}, my $v = {
+            mesh  => $mesh,
             color => $color,
         };
         
@@ -125,7 +128,25 @@ sub load_object {
 
 sub SetCuttingPlane {
     my ($self, $z) = @_;
+    
     $self->cutting_plane_z($z);
+    
+    # perform cut and cache section lines
+    my @verts = ();
+    foreach my $volume (@{$self->volumes}) {
+        foreach my $volume (@{$self->volumes}) {
+            my $expolygons = $volume->{mesh}->slice([ $z ])->[0];
+            $expolygons = offset_ex([ map @$_, @$expolygons ], scale 0.1);
+            
+            foreach my $line (map @{$_->lines}, map @$_, @$expolygons) {
+                push @verts, (
+                    unscale($line->a->x), unscale($line->a->y), $z,  #))
+                    unscale($line->b->x), unscale($line->b->y), $z,  #))
+                );
+            }
+        }
+    }
+    $self->cut_lines_vertices(OpenGL::Array->new_list(GL_FLOAT, @verts));
 }
 
 # Given an axis and angle, compute quaternion.
@@ -525,8 +546,16 @@ sub draw_mesh {
         }
         glDrawArrays(GL_TRIANGLES, 0, $volume->{verts}->elements / 3);
     }
-    
     glDisableClientState(GL_NORMAL_ARRAY);
+    glDisable(GL_BLEND);
+    glDisable(GL_CULL_FACE);
+    
+    if (defined $self->cutting_plane_z) {
+        glLineWidth(2);
+        glColor3f(0, 0, 0);
+        glVertexPointer_p(3, $self->cut_lines_vertices);
+        glDrawArrays(GL_LINES, 0, $self->cut_lines_vertices->elements / 3);
+    }
     glDisableClientState(GL_VERTEX_ARRAY);
 }
 
diff --git a/utils/view-mesh.pl b/utils/view-mesh.pl
index 120ddfe6d..680102405 100644
--- a/utils/view-mesh.pl
+++ b/utils/view-mesh.pl
@@ -19,6 +19,7 @@ my %opt = ();
 {
     my %options = (
         'help'                  => sub { usage() },
+        'cut=f'                 => \$opt{cut},
     );
     GetOptions(%options) or usage(1);
     $ARGV[0] or usage(1);
@@ -32,6 +33,7 @@ my %opt = ();
     
     $Slic3r::ViewMesh::object = $model->objects->[0];
     my $app = Slic3r::ViewMesh->new;
+    $app->{canvas}->SetCuttingPlane($opt{cut}) if defined $opt{cut};
     $app->MainLoop;
 }
 
@@ -43,6 +45,7 @@ sub usage {
 Usage: view-mesh.pl [ OPTIONS ] file.stl
 
     --help              Output this usage screen and exit
+    --cut Z             Display the cutting plane at the given Z
     
 EOF
     exit ($exit_code || 0);
@@ -61,7 +64,7 @@ sub OnInit {
     my $panel = Wx::Panel->new($frame, -1);
     
     my $sizer = Wx::BoxSizer->new(wxVERTICAL);
-    $sizer->Add(Slic3r::GUI::PreviewCanvas->new($panel, $object), 1, wxEXPAND, 0);
+    $sizer->Add($self->{canvas} = Slic3r::GUI::PreviewCanvas->new($panel, $object), 1, wxEXPAND, 0);
     $panel->SetSizer($sizer);
     $sizer->SetSizeHints($panel);