From 4862d832b535d0bfe0235f124621cddf0a8bca9f Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Fri, 9 Aug 2013 19:46:20 +0200
Subject: [PATCH] Simplify layer change code now that we have distinct support
 layers

---
 lib/Slic3r/GCode.pm       |  4 ++--
 lib/Slic3r/GCode/Layer.pm | 24 ++++++------------------
 lib/Slic3r/Print.pm       |  6 +++++-
 3 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/lib/Slic3r/GCode.pm b/lib/Slic3r/GCode.pm
index 6c58b2dbb..873479ec5 100644
--- a/lib/Slic3r/GCode.pm
+++ b/lib/Slic3r/GCode.pm
@@ -17,7 +17,6 @@ has 'layer'              => (is => 'rw');
 has '_layer_islands'     => (is => 'rw');
 has '_upper_layer_islands'  => (is => 'rw');
 has '_layer_overhangs'   => (is => 'rw');
-has 'move_z_callback'    => (is => 'rw');
 has 'shift_x'            => (is => 'rw', default => sub {0} );
 has 'shift_y'            => (is => 'rw', default => sub {0} );
 has 'z'                  => (is => 'rw');
@@ -132,6 +131,8 @@ sub change_layer {
             $gcode .= $self->set_acceleration($self->config->default_acceleration);
         }
     }
+    
+    $gcode .= $self->move_z($layer->print_z);
     return $gcode;
 }
 
@@ -153,7 +154,6 @@ sub move_z {
         $self->speed('travel');
         $gcode .= $self->G0(undef, $z, 0, $comment || ('move to next layer (' . $self->layer->id . ')'))
             if !defined $self->z || abs($z - ($self->z - $self->lifted)) > epsilon;
-        $gcode .= $self->move_z_callback->() if defined $self->move_z_callback;
     } elsif ($z < $self->z && $z > ($self->z - $self->lifted + epsilon)) {
         # we're moving to a layer height which is greater than the nominal current one
         # (nominal = actual - lifted) and less than the actual one.  we're basically
diff --git a/lib/Slic3r/GCode/Layer.pm b/lib/Slic3r/GCode/Layer.pm
index 307ab0e32..1b21b3fca 100644
--- a/lib/Slic3r/GCode/Layer.pm
+++ b/lib/Slic3r/GCode/Layer.pm
@@ -46,23 +46,16 @@ sub process_layer {
         $self->second_layer_things_done(1);
     }
     
-    # set new layer, but don't move Z as support material contact areas may need an intermediate one
+    # set new layer - this will change Z and force a retraction if retract_layer_change is enabled
     $gcode .= $self->gcodegen->change_layer($layer);
-    
-    # prepare callback to call as soon as a Z command is generated
-    $self->gcodegen->move_z_callback(sub {
-        $self->gcodegen->move_z_callback(undef);  # circular ref or not?
-        return "" if !$Slic3r::Config->layer_gcode;
-        return $Slic3r::Config->replace_options($Slic3r::Config->layer_gcode, {
-            layer_num => $self->gcodegen->layer->id,
-        }) . "\n";
-    });
+    $gcode .= $Slic3r::Config->replace_options($Slic3r::Config->layer_gcode, {
+        layer_num => $self->gcodegen->layer->id,
+    }) . "\n" if $Slic3r::Config->layer_gcode;
     
     # extrude skirt
     if ((values %{$self->skirt_done}) < $Slic3r::Config->skirt_height && !$self->skirt_done->{$layer->print_z}) {
         $self->gcodegen->set_shift(@{$self->shift});
-        $gcode .= $self->gcodegen->set_extruder($self->extruders->[0]);  # move_z requires extruder
-        $gcode .= $self->gcodegen->move_z($layer->print_z);
+        $gcode .= $self->gcodegen->set_extruder($self->extruders->[0]);
         # skip skirt if we have a large brim
         if ($layer->id < $Slic3r::Config->skirt_height) {
             # distribute skirt loops across all extruders
@@ -81,8 +74,7 @@ sub process_layer {
     
     # extrude brim
     if (!$self->brim_done) {
-        $gcode .= $self->gcodegen->set_extruder($self->extruders->[$Slic3r::Config->support_material_extruder-1]);  # move_z requires extruder
-        $gcode .= $self->gcodegen->move_z($layer->print_z);
+        $gcode .= $self->gcodegen->set_extruder($self->extruders->[$Slic3r::Config->support_material_extruder-1]);
         $self->gcodegen->set_shift(@{$self->shift});
         $gcode .= $self->gcodegen->extrude_loop($_, 'brim') for @{$self->print->brim};
         $self->brim_done(1);
@@ -98,7 +90,6 @@ sub process_layer {
         # extrude support material before other things because it might use a lower Z
         # and also because we avoid travelling on other things when printing it
         if ($self->print->has_support_material && $layer->isa('Slic3r::Layer::Support')) {
-            $gcode .= $self->gcodegen->move_z($layer->print_z);
             if ($layer->support_interface_fills) {
                 $gcode .= $self->gcodegen->set_extruder($self->extruders->[$Slic3r::Config->support_material_interface_extruder-1]);
                 $gcode .= $self->gcodegen->extrude_path($_, 'support material interface') 
@@ -111,9 +102,6 @@ sub process_layer {
             }
         }
         
-        # set actual Z - this will force a retraction
-        $gcode .= $self->gcodegen->move_z($layer->print_z);
-        
         # tweak region ordering to save toolchanges
         my @region_ids = 0 .. ($self->print->regions_count-1);
         if ($self->gcodegen->multiple_extruders) {
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index ac75f542c..544851915 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -732,7 +732,7 @@ sub write_gcode {
     # set up our extruder object
     my $gcodegen = Slic3r::GCode->new(
         config              => $self->config,
-        extruders           => $self->extruders,
+        extruders           => $self->extruders,    # we should only pass the *used* extruders (but maintain the Tx indices right!)
         layer_count         => $self->layer_count,
     );
     print $fh "G21 ; set units to millimeters\n" if $Slic3r::Config->gcode_flavor ne 'makerware';
@@ -768,6 +768,10 @@ sub write_gcode {
         }
     }
     
+    # always start with first extruder
+    # TODO: make sure we select the first *used* extruder
+    print $fh $gcodegen->set_extruder($self->extruders->[0]);
+    
     # calculate X,Y shift to center print around specified origin
     my $print_bb = $self->bounding_box;
     my $print_size = $print_bb->size;