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

        public ArrayList FindOrganismsInCells(int minGridX, int maxGridX, int minGridY, int maxGridY)
        {
            Debug.Assert(IndexBuilt);

            Debug.Assert(minGridX <= maxGridX && minGridY <= maxGridY);
            Debug.Assert(minGridX >= 0 && maxGridX < _gridWidth && minGridY >= 0 && maxGridY < _gridHeight);

            OrganismState lastFound = null;

            // Since organisms are represented at multiple places in the grid, make
            // sure we only get one instance
            var foundHash = new Hashtable();
            var foundOrganisms = new ArrayList();
            for (var x = minGridX; x <= maxGridX; x++)
            {
                for (var y = minGridY; y <= maxGridY; y++)
                {
                    var current = _cellOrganisms[x, y];
                    if (current == null) continue;

                    // If it's the same as the last one, skip the hashable lookup
                    // since it's expensive and we'll often find the same organism over and over
                    // in a row
                    if (lastFound != null && lastFound == current) continue;
                    if (foundHash[current] == null)
                    {
                        foundHash[current] = current;
                        foundOrganisms.Add(current);
                    }

                    lastFound = current;
                }
            }

            return foundOrganisms;
        }