From 2275de9f0dd8a58ff60d4b2794a83c8083a42ff8 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Sun, 10 Mar 2013 11:37:16 +0100
Subject: [PATCH] Factored out the layer height logic

---
 lib/Slic3r/Layer.pm        | 34 +++-------------------------------
 lib/Slic3r/Print/Object.pm | 22 +++++++++++++++++++++-
 2 files changed, 24 insertions(+), 32 deletions(-)

diff --git a/lib/Slic3r/Layer.pm b/lib/Slic3r/Layer.pm
index 951805c8a..074baef55 100644
--- a/lib/Slic3r/Layer.pm
+++ b/lib/Slic3r/Layer.pm
@@ -10,9 +10,9 @@ has 'object'            => (is => 'ro', weak_ref => 1, required => 1);
 has 'regions'           => (is => 'ro', default => sub { [] });
 has 'slicing_errors'    => (is => 'rw');
 
-has 'slice_z'           => (is => 'lazy');
-has 'print_z'           => (is => 'lazy');
-has 'height'            => (is => 'lazy');
+has 'slice_z'           => (is => 'ro', required => 1); # Z used for slicing in scaled coordinates
+has 'print_z'           => (is => 'ro', required => 1); # Z used for printing in scaled coordinates
+has 'height'            => (is => 'ro', required => 1); # layer height in unscaled coordinates
 
 # collection of expolygons generated by slicing the original geometry;
 # also known as 'islands' (all regions are merged here)
@@ -28,34 +28,6 @@ sub _trigger_id {
     $_->_trigger_layer for @{$self->regions || []};
 }
 
-# Z used for slicing in scaled coordinates
-sub _build_slice_z {
-    my $self = shift;
-    
-    if ($Slic3r::Config->raft_layers == 0) {
-        if ($self->id == 0) {
-            return scale $Slic3r::Config->get_value('first_layer_height') / 2;
-        }
-        return scale($Slic3r::Config->get_value('first_layer_height') + ($self->id-1 + 0.5) * $Slic3r::Config->layer_height);
-    } else {
-        return -1 if $self->id < $Slic3r::Config->raft_layers;
-        my $object_layer_id = $self->id - $Slic3r::Config->raft_layers;
-        return scale ($object_layer_id + 0.5) * $Slic3r::Config->layer_height;
-    }
-}
-
-# Z used for printing in scaled coordinates
-sub _build_print_z {
-    my $self = shift;
-    return ($Slic3r::Config->get_value('first_layer_height') + ($self->id * $Slic3r::Config->layer_height)) / &Slic3r::SCALING_FACTOR;
-}
-
-# layer height in unscaled coordinates
-sub _build_height {
-    my $self = shift;
-    return $self->id == 0 ? $Slic3r::Config->get_value('first_layer_height') : $Slic3r::Config->layer_height;
-}
-
 # layer height of contact paths in unscaled coordinates
 sub support_material_contact_height {
     my $self = shift;
diff --git a/lib/Slic3r/Print/Object.pm b/lib/Slic3r/Print/Object.pm
index c77fd228f..094dd026a 100644
--- a/lib/Slic3r/Print/Object.pm
+++ b/lib/Slic3r/Print/Object.pm
@@ -18,10 +18,30 @@ sub BUILD {
     my $self = shift;
  	 
     # make layers
+    my $print_z = my $slice_z = my $raft_z = 0;
     while (!@{$self->layers} || $self->layers->[-1]->slice_z < $self->size->[Z]) {
+        my $id = $#{$self->layers} + 1;
+        my $height = $id == 0
+            ? $Slic3r::Config->get_value('first_layer_height')
+            : $Slic3r::Config->layer_height;
+        $print_z += $height;
+        
+        if ($id < $Slic3r::Config->raft_layers) {
+            # this is a raft layer
+            $raft_z += $height;
+            $slice_z = -1;
+        } else {
+            $slice_z = $print_z - ($height/2) - $raft_z;
+        }
+        
+        ### Slic3r::debugf "Layer %d: height = %s; slice_z = %s; print_z = %s\n", $id, $height, $slice_z, $print_z;
+        
         push @{$self->layers}, Slic3r::Layer->new(
             object  => $self,
-            id      => $#{$self->layers} + 1,
+            id      => $id,
+            height  => $height,
+            print_z => scale $print_z,
+            slice_z => scale $slice_z,
         );
     }
 }