From 9b9ed91e6e013d4be7b8ddee279ef7318e9048b3 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Wed, 7 Jan 2015 20:45:50 +0100
Subject: [PATCH] Nicer rendering for 3D slices

---
 lib/Slic3r/GUI/PreviewCanvas.pm | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/Slic3r/GUI/PreviewCanvas.pm b/lib/Slic3r/GUI/PreviewCanvas.pm
index 325d39bc1..c0188edde 100644
--- a/lib/Slic3r/GUI/PreviewCanvas.pm
+++ b/lib/Slic3r/GUI/PreviewCanvas.pm
@@ -874,9 +874,13 @@ sub draw_volumes {
                                 glLineWidth(0);
                                 glColor3f(@{COLORS->[0]});
                                 glBegin(GL_QUADS);
-                                glNormal3f((map $_/$line->length, @{$line->normal}), 0);
+                                # We'll use this for the middle normal when using 4 quads:
+                                #my $xy_normal = $line->normal;
+                                #$_xynormal->scale(1/$line->length);
+                                glNormal3f(0,0,-1);
                                 glVertex3f((map unscale($_), @{$line->a}), $bottom_z);
                                 glVertex3f((map unscale($_), @{$line->b}), $bottom_z);
+                                glNormal3f(0,0,1);
                                 glVertex3f((map unscale($_), @{$line->b}), $top_z);
                                 glVertex3f((map unscale($_), @{$line->a}), $top_z);
                                 glEnd();