private void FindPathToWater(WorldTile tile, Direction direction, ref River river)
{
if (tile.TerrainData.Rivers.Contains(river))
{
return;
}
// check if there is already a river on this tile
if (tile.TerrainData.Rivers.Count > 0)
{
river.Intersections++;
}
river.AddTile(tile);
// get neighbors
WorldTile left = GetLeft(tile);
WorldTile right = GetRight(tile);
WorldTile top = GetTop(tile);
WorldTile 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.TerrainData.HeightValue;
}
if (right != null && right.GetRiverNeighborCount(river) < 2 && !river.Tiles.Contains(right))
{
rightValue = right.TerrainData.HeightValue;
}
if (top != null && top.GetRiverNeighborCount(river) < 2 && !river.Tiles.Contains(top))
{
topValue = top.TerrainData.HeightValue;
}
if (bottom != null && bottom.GetRiverNeighborCount(river) < 2 && !river.Tiles.Contains(bottom))
{
bottomValue = bottom.TerrainData.HeightValue;
}
// if neighbor is existing river that is not this one, flow into it
if (bottom != null && bottom.TerrainData.Rivers.Count == 0 && !bottom.TerrainData.Collidable)
{
bottomValue = 0;
}
if (top != null && top.TerrainData.Rivers.Count == 0 && !top.TerrainData.Collidable)
{
topValue = 0;
}
if (left != null && left.TerrainData.Rivers.Count == 0 && !left.TerrainData.Collidable)
{
leftValue = 0;
}
if (right != null && right.TerrainData.Rivers.Count == 0 && !right.TerrainData.Collidable)
{
rightValue = 0;
}
// override flow direction if a tile is significantly lower
if (direction == Direction.Left)
{
if (Math.Abs(rightValue - leftValue) < 0.1f)
{
rightValue = int.MaxValue;
}
}
if (direction == Direction.Right)
{
if (Math.Abs(rightValue - leftValue) < 0.1f)
{
leftValue = int.MaxValue;
}
}
if (direction == Direction.Top)
{
if (Math.Abs(topValue - bottomValue) < 0.1f)
{
bottomValue = int.MaxValue;
}
}
if (direction == Direction.Bottom)
{
if (Math.Abs(topValue - bottomValue) < 0.1f)
{
topValue = int.MaxValue;
}
}
// find mininum
float min = Math.Min(Math.Min(Math.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.TerrainData.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.TerrainData.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.TerrainData.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.TerrainData.Collidable)
{
if (river.CurrentDirection != Direction.Top)
{
river.TurnCount++;
river.CurrentDirection = Direction.Top;
}
FindPathToWater(top, direction, ref river);
}
}
}