From f24ca220d5dd57b4d7cfe444281511bd5c592270 Mon Sep 17 00:00:00 2001
From: Florens Wasserfall <wasserfall@kalanka.de>
Date: Tue, 4 Apr 2017 16:25:00 +0200
Subject: [PATCH] fix potential endless loop when evaluating the spline

---
 xs/src/libslic3r/LayerHeightSpline.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/xs/src/libslic3r/LayerHeightSpline.cpp b/xs/src/libslic3r/LayerHeightSpline.cpp
index f2997a1d9..1e8da6cfe 100644
--- a/xs/src/libslic3r/LayerHeightSpline.cpp
+++ b/xs/src/libslic3r/LayerHeightSpline.cpp
@@ -158,15 +158,18 @@ std::vector<coordf_t> LayerHeightSpline::getInterpolatedLayers() const
         coordf_t z = this->_original_layers[0];
         coordf_t h;
         coordf_t h_diff = 0;
+        coordf_t last_h_diff = 0;
         coordf_t eps = 0.0001;
         while(z <= this->_object_height) {
             h = 0;
+            h_diff = 0;
             // find intersection between layer height and spline
             do {
+                last_h_diff = h_diff;
                 h += h_diff/2;
                 h = this->_layer_height_spline->evaluate(z+h);
                 h_diff = this->_layer_height_spline->evaluate(z+h) - h;
-            } while(std::abs(h_diff) > eps);
+            } while(std::abs(h_diff) > eps && std::abs(h_diff - last_h_diff) > eps);
             z += h;
             layers.push_back(z);
         }