From 211146e5dead64c14459c0eb872c2ff2b7ee8890 Mon Sep 17 00:00:00 2001
From: Filip Sykala - NTB T15p <Filip.Sykala@Prusa3D.cz>
Date: Wed, 27 Sep 2023 14:37:00 +0200
Subject: [PATCH] Fix calculation of up vector angle.

---
 src/libslic3r/Emboss.cpp   | 11 +++--------
 src/libslic3r/Geometry.hpp |  3 ++-
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/libslic3r/Emboss.cpp b/src/libslic3r/Emboss.cpp
index 0fed283a0c..7afccda67e 100644
--- a/src/libslic3r/Emboss.cpp
+++ b/src/libslic3r/Emboss.cpp
@@ -1647,22 +1647,17 @@ std::optional<float> Emboss::calc_up(const Transform3d &tr, double up_limit)
     Vec3d normal = tr_linear.col(2);
     // scaled matrix has base with different size
     normal.normalize();
-    Vec3d suggested = suggest_up(normal);
+    Vec3d suggested = suggest_up(normal, up_limit);
     assert(is_approx(suggested.squaredNorm(), 1.));
 
     Vec3d up = tr_linear.col(1); // tr * UnitY()
-    up.normalize();
-    
-    double dot = suggested.dot(up);
-    if (dot >= 1. || dot <= -1.)
-        return {}; // zero angle
-
+    up.normalize();    
     Matrix3d m;
     m.row(0) = up;
     m.row(1) = suggested;
     m.row(2) = normal;
     double det = m.determinant();
-
+    double dot = suggested.dot(up);
     return -atan2(det, dot);
 }
 
diff --git a/src/libslic3r/Geometry.hpp b/src/libslic3r/Geometry.hpp
index 0d6e921d5c..c5d81bda54 100644
--- a/src/libslic3r/Geometry.hpp
+++ b/src/libslic3r/Geometry.hpp
@@ -317,9 +317,10 @@ template<typename T> T angle_to_0_2PI(T angle)
     return angle;
 }
 template<typename T> void to_range_pi_pi(T &angle){
-    if (angle > T(PI) || angle < -T(PI)) {
+    if (angle > T(PI) || angle <= -T(PI)) {
         int count = static_cast<int>(std::round(angle / (2 * PI)));
         angle -= static_cast<T>(count * 2 * PI);
+        assert(angle <= T(PI) && angle > -T(PI));
     }
 }