Generator.FindPathToWater C# (CSharp) Method

	private void FindPathToWater(Tile tile, Direction direction, ref River river)
	{
		if (tile.Rivers.Contains (river))
			return;

		// check if there is already a river on this tile
		if (tile.Rivers.Count > 0)
			river.Intersections++;

		river.AddTile (tile);

		// get neighbors
		Tile left = GetLeft (tile);
		Tile right = GetRight (tile);
		Tile top = GetTop (tile);
		Tile bottom = GetBottom (tile);
		
		float leftValue = int.MaxValue;
		float rightValue = int.MaxValue;
		float topValue = int.MaxValue;
		float bottomValue = int.MaxValue;
		
		// query height values of neighbors
		if (left != null && left.GetRiverNeighborCount(river) < 2 && !river.Tiles.Contains(left)) 
			leftValue = left.HeightValue;
		if (right != null && right.GetRiverNeighborCount(river) < 2 && !river.Tiles.Contains(right)) 
			rightValue = right.HeightValue;
		if (top != null && top.GetRiverNeighborCount(river) < 2 && !river.Tiles.Contains(top)) 
			topValue = top.HeightValue;
		if (bottom != null && bottom.GetRiverNeighborCount(river) < 2 && !river.Tiles.Contains(bottom)) 
			bottomValue = bottom.HeightValue;
		
		// if neighbor is existing river that is not this one, flow into it
		if (bottom != null && bottom.Rivers.Count == 0 && !bottom.Collidable)
			bottomValue = 0;
		if (top != null && top.Rivers.Count == 0 && !top.Collidable)
			topValue = 0;
		if (left != null && left.Rivers.Count == 0 && !left.Collidable)
			leftValue = 0;
		if (right != null && right.Rivers.Count == 0 && !right.Collidable)
			rightValue = 0;
		
		// override flow direction if a tile is significantly lower
		if (direction == Direction.Left)
			if (Mathf.Abs (rightValue - leftValue) < 0.1f)
				rightValue = int.MaxValue;
		if (direction == Direction.Right)
			if (Mathf.Abs (rightValue - leftValue) < 0.1f)
				leftValue = int.MaxValue;
		if (direction == Direction.Top)
			if (Mathf.Abs (topValue - bottomValue) < 0.1f)
				bottomValue = int.MaxValue;
		if (direction == Direction.Bottom)
			if (Mathf.Abs (topValue - bottomValue) < 0.1f)
				topValue = int.MaxValue;
		
		// find mininum
		float min = Mathf.Min (Mathf.Min (Mathf.Min (leftValue, rightValue), topValue), bottomValue);
		
		// if no minimum found - exit
		if (min == int.MaxValue)
			return;
		
		//Move to next neighbor
		if (min == leftValue) {
			if (left != null && left.Collidable)
			{
				if (river.CurrentDirection != Direction.Left){
					river.TurnCount++;
					river.CurrentDirection = Direction.Left;
				}
				FindPathToWater (left, direction, ref river);
			}
		} else if (min == rightValue) {
			if (right != null && right.Collidable)
			{
				if (river.CurrentDirection != Direction.Right){
					river.TurnCount++;
					river.CurrentDirection = Direction.Right;
				}
				FindPathToWater (right, direction, ref river);
			}
		} else if (min == bottomValue) {
			if (bottom != null && bottom.Collidable)
			{
				if (river.CurrentDirection != Direction.Bottom){
					river.TurnCount++;
					river.CurrentDirection = Direction.Bottom;
				}
				FindPathToWater (bottom, direction, ref river);
			}
		} else if (min == topValue) {
			if (top != null && top.Collidable)
			{
				if (river.CurrentDirection != Direction.Top){
					river.TurnCount++;
					river.CurrentDirection = Direction.Top;
				}
				FindPathToWater (top, direction, ref river);
			}
		}
	}