+ // maintain ~2.5% gas composition
+ double gas_amount = GetCreature().GetComposition().Get(gas);
+ if (gas_amount < GetCreature().GetComposition().TotalMass() * 0.025) {
+ double add = std::min(GetCreature().GetComposition().TotalMass() * 0.025 - gas_amount, -amount * dt);
+ GetCreature().Ingest(gas, add);
+ }