Terrarium.Game.WorldState.AddOrganism C# (CSharp) Method

        public void AddOrganism(OrganismState state)
        {
            if (IsImmutable)
            {
                throw new ApplicationException("WorldState must be mutable to add organisms.");
            }

            Debug.Assert(state.GridX >= 0 && state.GridX < _gridWidth && state.GridY >= 0 && state.GridY < _gridHeight);
            Debug.Assert(_cellOrganisms[state.GridX, state.GridY] == null);

            if (_organisms.ContainsKey(state.ID))
            {
                throw new OrganismAlreadyExistsException();
            }

            FillCells(state, state.GridX, state.GridY, state.CellRadius, false);

            // Lock the size and position since we've added it to the index and these shouldn't be changed now
            state.LockSizeAndPosition();

            _organisms.Add(state.ID, state);
        }