From b88ab02d1cda215691c66fc790994f929421d9d6 Mon Sep 17 00:00:00 2001
From: PavelMikus <pavel.mikus.mail@seznam.cz>
Date: Fri, 20 May 2022 11:26:07 +0200
Subject: [PATCH] additional minor fixes and simplifications

---
 src/libslic3r/GCode/SeamPlacer.cpp | 14 ++++++--------
 src/libslic3r/GCode/SeamPlacer.hpp |  9 +++++++--
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/src/libslic3r/GCode/SeamPlacer.cpp b/src/libslic3r/GCode/SeamPlacer.cpp
index 8fe8a31b8c..e7171ee7cb 100644
--- a/src/libslic3r/GCode/SeamPlacer.cpp
+++ b/src/libslic3r/GCode/SeamPlacer.cpp
@@ -678,7 +678,8 @@ struct SeamComparator {
         }
 
         //avoid overhangs
-        if (a.overhang > 0.1f || b.overhang > 0.1f) {
+        if (a.overhang > SeamPlacer::overhang_distance_tolerance_factor * a.perimeter.flow_width ||
+                b.overhang > SeamPlacer::overhang_distance_tolerance_factor * b.perimeter.flow_width) {
             return a.overhang < b.overhang;
         }
 
@@ -738,7 +739,8 @@ struct SeamComparator {
         }
 
         //avoid overhangs
-        if (a.overhang > 0.1f || b.overhang > 0.1f) {
+        if (a.overhang > SeamPlacer::overhang_distance_tolerance_factor * a.perimeter.flow_width ||
+                b.overhang > SeamPlacer::overhang_distance_tolerance_factor * b.perimeter.flow_width) {
             return a.overhang < b.overhang;
         }
 
@@ -761,7 +763,6 @@ struct SeamComparator {
             return a.position.y() > b.position.y();
         }
 
-        //ranges:          [0 - 1]                                          (0 - 1.3]                  ;
         float penalty_a = a.visibility
                 + SeamPlacer::angle_importance * compute_angle_penalty(a.local_ccw_angle);
         float penalty_b = b.visibility +
@@ -780,11 +781,8 @@ struct SeamComparator {
         // looks scary, but it is gaussian combined with sigmoid,
         // so that concave points have much smaller penalty over convex ones
         // https://github.com/prusa3d/PrusaSlicer/tree/master/doc/seam_placement/corner_penalty_function.png
-        float f_value = gauss(ccw_angle, 0.0f, 1.0f, 3.0f) +
-                1.0f / (2 + std::exp(-ccw_angle)); // sigmoid, which heavily favourizes concave angles
-        //NOTE for very small angles, the noise in the angle computation cause aligned lines curving.
-        //for this reason, the value will be clamped to 1.2 value, throwing away angles roughly smaller than 30 degrees
-        return std::min(f_value, 1.2f);
+        return gauss(ccw_angle, 0.0f, 1.0f, 3.0f) +
+                1.0f / (2 + std::exp(-ccw_angle));
     }
 };
 
diff --git a/src/libslic3r/GCode/SeamPlacer.hpp b/src/libslic3r/GCode/SeamPlacer.hpp
index 23f165a583..fe2d88b7d5 100644
--- a/src/libslic3r/GCode/SeamPlacer.hpp
+++ b/src/libslic3r/GCode/SeamPlacer.hpp
@@ -121,6 +121,11 @@ public:
     // arm length used during angles computation
     static constexpr float polygon_local_angles_arm_distance = 0.1f;
 
+
+    // max tolerable distance from the previous layer is overhang_distance_tolerance_factor * flow_width
+    static constexpr float overhang_distance_tolerance_factor = 0.5f;
+
+
     // determines angle importance compared to visibility ( neutral value is 1.0f. )
     static constexpr float angle_importance = 0.7f;
 
@@ -131,7 +136,7 @@ public:
 
     // When searching for seam clusters for alignment:
     // following value describes, how much worse score can point have and still be picked into seam cluster instead of original seam point on the same layer
-    static constexpr float seam_align_score_tolerance = 0.2f;
+    static constexpr float seam_align_score_tolerance = 0.27f;
     // seam_align_tolerable_dist - if next layer closes point is too far away, break string
     static constexpr float seam_align_tolerable_dist = 1.0f;
     // if the seam of the current layer is too far away, and the closest seam candidate is not very good, layer is skipped.
@@ -140,7 +145,7 @@ public:
     // minimum number of seams needed in cluster to make alignment happen
     static constexpr size_t seam_align_minimum_string_seams = 6;
     // points covered by spline; determines number of splines for the given string
-    static constexpr size_t seam_align_seams_per_segment = 14;
+    static constexpr size_t seam_align_seams_per_segment = 8;
 
     //The following data structures hold all perimeter points for all PrintObject.
     std::unordered_map<const PrintObject*, PrintObjectSeamData> m_seam_per_object;