Send EVT_SLICING_UPDATE with RELOAD_SLA_SUPPORT_POINTS

once object's support points are calculated by the backend.

src/libslic3r/PrintBase.hpp

@@ -244,8 +244,9 @@ public:
         // Bitmap of flags.
         enum FlagBits {
             DEFAULT,
-            NO_RELOAD_SCENE = 0,
-            RELOAD_SCENE = 1,
+            NO_RELOAD_SCENE                 = 0,
+            RELOAD_SCENE                    = 1 << 1,
+            RELOAD_SLA_SUPPORT_POINTS       = 1 << 2,
         };
         // Bitmap of FlagBits
         unsigned int    flags;

src/libslic3r/SLAPrint.cpp

@@ -552,6 +552,9 @@ void SLAPrint::process()
 
             BOOST_LOG_TRIVIAL(debug) << "Automatic support points: "
                                      << po.m_supportdata->support_points.rows();
+
+            // Using RELOAD_SLA_SUPPORT_POINTS to tell the Plater to pass the update status to GLGizmoSlaSupports
+            report_status(*this, -1, L("Generating support points"), SlicingStatus::RELOAD_SLA_SUPPORT_POINTS);
         }
         else {
             // There are some points on the front-end, no calculation will be done.

src/slic3r/GUI/Plater.cpp

@@ -2229,6 +2229,9 @@ void Plater::priv::on_slicing_update(SlicingStatusEvent &evt)
             break;
         }
     }
+    if (evt.status.flags & PrintBase::SlicingStatus::RELOAD_SLA_SUPPORT_POINTS) {
+        // Update SLA gizmo
+    }
 }
 
 void Plater::priv::on_slicing_completed(wxCommandEvent &)