[GL] Extract GeoLib::markUsedPoints() for surfaces

Applications/Utils/GeoTools/RemoveUnusedPoints.cpp

@@ -92,13 +92,7 @@ int main(int argc, char* argv[])
     {
         for (auto const* surface : *surfaces)
         {
-            for (std::size_t i = 0; i < surface->getNumberOfTriangles(); ++i)
-            {
-                auto const* triangle = (*surface)[i];
-                used_points[(*triangle)[0]] = true;
-                used_points[(*triangle)[1]] = true;
-                used_points[(*triangle)[2]] = true;
-            }
+            GeoLib::markUsedPoints(*surface, used_points);
         }
     }
 

GeoLib/Surface.cpp

@@ -129,4 +129,23 @@ void resetPointIDs(Surface& surface, std::vector<std::size_t> const& mapping)
     }
 }
 
+void markUsedPoints(Surface const& surface, std::vector<bool>& used_points)
+{
+    if (surface.getPointVec()->size() != used_points.size())
+    {
+        OGS_FATAL(
+            "internal error in markUsedPoints(): surface based on point vector "
+            "of size {}, given used_points has size {}",
+            surface.getPointVec()->size(), used_points.size());
+    }
+    for (std::size_t i = 0; i < surface.getNumberOfTriangles(); ++i)
+    {
+        auto const& triangle = *surface[i];
+        for (std::size_t k = 0; k < 3; ++k)
+        {
+            used_points[triangle[k]] = true;
+        }
+    }
+}
+
 }  // namespace GeoLib

GeoLib/Surface.h

@@ -97,4 +97,5 @@ bool operator==(Surface const& lhs, Surface const& rhs);
 /// Resets the point IDs of the surface corresponding to the mapping.
 void resetPointIDs(Surface& surface, std::vector<std::size_t> const& mapping);
 
+void markUsedPoints(Surface const& surface, std::vector<bool>& used_points);
 }  // namespace GeoLib