FIX: scarf angle only check seam point angle

Jira: 6681

Signed-off-by: qing.zhang <qing.zhang@bambulab.com>
Change-Id: I2d7a3e76c2a307bef8d6816814e7fef4bb6909ff

src/libslic3r/ExtrusionEntity.cpp

@@ -426,8 +426,8 @@ double ExtrusionLoop::min_mm3_per_mm() const
 }
 
 // Orca: This function is used to check if the loop is smooth(continuous) or not.
-// TODO: the main logic is largly copied from the calculate_polygon_angles_at_vertices function in SeamPlacer file. Need to refactor the code in the future.
-bool ExtrusionLoop::is_smooth(double angle_threshold, double min_arm_length) const
+//BBS: only check angle of seam point while the seam has been decided.
+bool ExtrusionLoop::check_seam_point_angle(double angle_threshold, double min_arm_length) const
 {
     // go through all the points in the loop and check if the angle between two segments(AB and BC) is less than the threshold
     size_t idx_prev = 0;
@@ -450,31 +450,19 @@ bool ExtrusionLoop::is_smooth(double angle_threshold, double min_arm_length) con
         distance_to_prev += lengths[idx_prev];
     }
 
-    for (size_t _i = 0; _i < points.size(); ++_i) {
-        // pull idx_prev to current as much as possible, while respecting the min_arm_length
-        while (distance_to_prev - lengths[idx_prev] > min_arm_length) {
-            distance_to_prev -= lengths[idx_prev];
-            idx_prev = Slic3r::next_idx_modulo(idx_prev, points.size());
-        }
+    // push idx_next forward as far as needed
+    while (distance_to_next < min_arm_length) {
+        distance_to_next += lengths[idx_next];
+        idx_next = Slic3r::next_idx_modulo(idx_next, points.size());
+    }
 
-        // push idx_next forward as far as needed
-        while (distance_to_next < min_arm_length) {
-            distance_to_next += lengths[idx_next];
-            idx_next = Slic3r::next_idx_modulo(idx_next, points.size());
-        }
-
-        // Calculate angle between idx_prev, idx_curr, idx_next.
-        const Point &p0 = points[idx_prev];
-        const Point &p1 = points[idx_curr];
-        const Point &p2 = points[idx_next];
-        const auto   a  = angle(p0 - p1, p2 - p1);
-        if (a > 0 ? a < angle_threshold : a > -angle_threshold) { return false; }
-
-        // increase idx_curr by one
-        float curr_distance = lengths[idx_curr];
-        idx_curr++;
-        distance_to_prev += curr_distance;
-        distance_to_next -= curr_distance;
+    // Calculate angle between idx_prev, idx_curr, idx_next.
+    const Point &p0 = points[idx_prev];
+    const Point &p1 = points[idx_curr];
+    const Point &p2 = points[idx_next];
+    const auto   a  = angle(p0 - p1, p2 - p1);
+    if (a > 0 ? a < angle_threshold : a > -angle_threshold) {
+        return false;
     }
 
     return true;

src/libslic3r/ExtrusionEntity.hpp

@@ -459,7 +459,7 @@ public:
     }
     double total_volume() const override { double volume =0.; for (const auto& path : paths) volume += path.total_volume(); return volume; }
     // check if the loop is smooth, angle_threshold is in radians, default is 10 degrees
-    bool is_smooth(double angle_threshold = 0.174, double min_arm_length = 0.025) const;
+    bool check_seam_point_angle(double angle_threshold = 0.174, double min_arm_length = 0.025) const;
     //static inline std::string role_to_string(ExtrusionLoopRole role);
 
 #ifndef NDEBUG

src/libslic3r/GCode.cpp

@@ -4037,7 +4037,8 @@ std::string GCode::extrude_loop(ExtrusionLoop loop, std::string description, dou
                                     !on_first_layer();
 
     if (enable_seam_slope && m_config.seam_slope_conditional.value) {
-        enable_seam_slope = loop.is_smooth(m_config.scarf_angle_threshold.value * M_PI / 180., EXTRUDER_CONFIG(nozzle_diameter));
+        //BBS: the seam has been decide, only check the seam position angle
+        enable_seam_slope = loop.check_seam_point_angle(m_config.scarf_angle_threshold.value * M_PI / 180.0);
     }
 
     // clip the path to avoid the extruder to get exactly on the first point of the loop;

src/libslic3r/PrintConfig.cpp

@@ -2863,7 +2863,7 @@ void PrintConfigDef::init_fff_params()
 
     def           = this->add("scarf_angle_threshold", coInt);
     def->label    = L("Conditional angle threshold");
-    def->tooltip  = L("This option sets the threshold angle for applying a conditional scarf joint seam.\nIf the maximum angle within the perimeter loop " "exceeds this value (indicating the absence of sharp corners), a scarf joint seam will be used. The default value is 155°.");
+    def->tooltip  = L("This option sets the threshold angle for applying a conditional scarf joint seam.\nIf the seam angle within the perimeter loop " "exceeds this value (indicating the absence of sharp corners), a scarf joint seam will be used. The default value is 155°.");
     def->mode     = comAdvanced;
     def->sidetext = L("°");
     def->min      = 0;