spline: fix deadzone when more than 2 points

1 files changed, 11 insertions, 2 deletions

diff --git a/spline/spline.cpp b/spline/spline.cpp
index 92e03ade..9f92c074 100644
--- a/spline/spline.cpp
+++ b/spline/spline.cpp
@@ -148,7 +148,7 @@ void spline::update_interp_data() const
 {
     points_t list = points;
     ensure_valid(list);
-    const int sz = list.size();
+    int sz = list.size();
 
     if (list.isEmpty())
         list.prepend({ max_input(), max_output() });
@@ -183,7 +183,16 @@ void spline::update_interp_data() const
     else
     {
         if (list[0].x() > 1e-6)
-            list.push_front({});
+        {
+            double zero_pos = 0;
+            while (list.size() > 1 && list[0].y() <= 1e-6)
+            {
+                zero_pos = list[0].x();
+                list.pop_front();
+            }
+            list.push_front({zero_pos, 0});
+            sz = list.size();
+        }
 
         // now this is hella expensive due to `c_interp'
         for (int i = 0; i < sz; i++)