TriangleSelector: edge limit is derived from cursor size

src/libslic3r/TriangleSelector.cpp

@@ -35,14 +35,20 @@ void TriangleSelector::Triangle::set_division(int sides_to_split, int special_si
 
 void TriangleSelector::select_patch(const Vec3f& hit, int facet_start,
                                     const Vec3f& source, const Vec3f& dir,
-                                    float radius_sqr, FacetSupportType new_state)
+                                    float radius, FacetSupportType new_state)
 {
     assert(facet_start < m_orig_size_indices);
     assert(is_approx(dir.norm(), 1.f));
 
     // Save current cursor center, squared radius and camera direction,
     // so we don't have to pass it around.
-    m_cursor = {hit, source, dir, radius_sqr};
+    m_cursor = {hit, source, dir, radius*radius};
+
+    // In case user changed cursor size since last time, update triangle edge limit.
+    if (m_old_cursor_radius != radius) {
+        set_edge_limit(radius / 5.f);
+        m_old_cursor_radius = radius;
+    }
 
     // Now start with the facet the pointer points to and check all adjacent facets.
     std::vector<int> facets_to_check{facet_start};

src/libslic3r/TriangleSelector.hpp

@@ -1,7 +1,7 @@
 #ifndef libslic3r_TriangleSelector_hpp_
 #define libslic3r_TriangleSelector_hpp_
 
-#define PRUSASLICER_TRIANGLE_SELECTOR_DEBUG
+// #define PRUSASLICER_TRIANGLE_SELECTOR_DEBUG
 
 
 #include "Point.hpp"
@@ -28,7 +28,7 @@ public:
                       int facet_start,     // facet that point belongs to
                       const Vec3f& source, // camera position (mesh coords)
                       const Vec3f& dir,    // direction of the ray (mesh coords)
-                      float radius_sqr,    // squared radius of the cursor
+                      float radius,        // radius of the cursor
                       FacetSupportType new_state);   // enforcer or blocker?
 
     // Get facets currently in the given state.
@@ -130,6 +130,7 @@ protected:
     };
 
     Cursor m_cursor;
+    float m_old_cursor_radius;
 
     // Private functions:
     bool select_triangle(int facet_idx, FacetSupportType type,

src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.cpp

@@ -404,7 +404,7 @@ bool GLGizmoFdmSupports::gizmo_event(SLAGizmoEventType action, const Vec2d& mous
         // FIXME: The scaling of the mesh can be non-uniform.
         const Vec3d sf = Geometry::Transformation(trafo_matrix).get_scaling_factor();
         const float avg_scaling = (sf(0) + sf(1) + sf(2))/3.;
-        const float limit = std::pow(m_cursor_radius/avg_scaling , 2.f);
+        const float limit = m_cursor_radius/avg_scaling;
 
         // Calculate direction from camera to the hit (in mesh coords):
         Vec3f camera_pos = (trafo_matrix.inverse() * camera.get_position()).cast<float>();

src/slic3r/GUI/Gizmos/GLGizmoFdmSupports.hpp

@@ -56,7 +56,7 @@ private:
     GLUquadricObj* m_quadric;
 
     float m_cursor_radius = 2.f;
-    static constexpr float CursorRadiusMin  = 0.f;
+    static constexpr float CursorRadiusMin  = 0.4f; // cannot be zero
     static constexpr float CursorRadiusMax  = 8.f;
     static constexpr float CursorRadiusStep = 0.2f;