Changes the way the mixed cells zones are stored to avoid SIGSEGV when a material interface is badly defined
requested to merge 23-sigsegv-when-applying-vtkmaterialinterface-filter-if-the-interface-is-not-correctly-defined into main
The main change in this MR is the type of the m_mixed_cells (renamed in m_mixed_cell_zones) which was a map of vector and is now a map of map.
It avoid creating couples (material_id, local_cell_id) with default values (0, 0) when resizing the vector. Thus it avoid using the m_material_collection through the [] operator with inexistant key leading to the use of default construct Material object with m_input_material_mesh=nullptr.
By the way, this MR forbid default construct of Material object because it cannot be used if m_input_material_mesh is nullptr.
Closes #23 (closed)
Edited by guillaume Peillex