-/// MaterialInfoTable::get_material_info() takes a position object as input,
-/// computes or looks up a MaterialInfo object, and returns a pointer to it.
-/// If the material configuration is not already present in the table, it
-/// is stored there, so we don't have to recompute everything when the
-/// same material configuration occurs again.
-
-MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) const {
-
- Key key = pos.get_material_key();
- MaterialInfo* mi = probe(key);
-
- // If mi->key matches the position's material hash key, it means that we