Generator.BuildRiverGroups C# (CSharp) Method

	private void BuildRiverGroups()
	{
		//loop each tile, checking if it belongs to multiple rivers
		for (var x = 0; x < Width; x++) {
			for (var y = 0; y < Height; y++) {
				Tile t = Tiles[x,y];

				if (t.Rivers.Count > 1)
				{
					// multiple rivers == intersection
					RiverGroup group = null;

					// Does a rivergroup already exist for this group?
					for (int n=0; n < t.Rivers.Count; n++)
					{
						River tileriver = t.Rivers[n];
						for (int i = 0; i < RiverGroups.Count; i++)
						{
							for (int j = 0; j < RiverGroups[i].Rivers.Count; j++)
							{
								River river = RiverGroups[i].Rivers[j];
								if (river.ID == tileriver.ID)
								{
									group = RiverGroups[i];
								}
								if (group != null) break;
							}
							if (group != null) break;
						}
						if (group != null) break;
					}

					// existing group found -- add to it
					if (group != null)
					{
						for (int n=0; n < t.Rivers.Count; n++)
						{
							if (!group.Rivers.Contains(t.Rivers[n]))
								group.Rivers.Add(t.Rivers[n]);
						}
					}
					else   //No existing group found - create a new one
					{
						group = new RiverGroup();
						for (int n=0; n < t.Rivers.Count; n++)
						{
							group.Rivers.Add(t.Rivers[n]);
						}
						RiverGroups.Add (group);
					}
				}
			}
		}	
	}