int CreateRiver(TriCell origin)
{
int length = 0;
TriCell cell = origin;
TriDirection direction = TriDirection.VERT;
while (!cell.IsUnderwater)
{
flowDirections.Clear();
for (TriDirection d = TriDirection.VERT; d <= TriDirection.RIGHT; d++)
{
TriCell neighbor = cell.GetNeighbor(d);
if (!neighbor || neighbor.HasRiver)
{
continue;
}
int delta = neighbor.Elevation - cell.Elevation;
if (delta > 0)
{
continue;
}
if (delta < 0)
{
flowDirections.Add(d);
flowDirections.Add(d);
flowDirections.Add(d);
}
if (
length == 1 ||
(d != direction.Next2() && d != direction.Previous2())
)
{
flowDirections.Add(d);
}
flowDirections.Add(d);
}
if (flowDirections.Count == 0)
{
return(length > 1 ? length : 0);
}
direction = flowDirections[Random.Range(0, flowDirections.Count)];
cell.SetRiver(direction);
cell.GetNeighbor(direction).SetRiver(direction);
length += 1;
cell = cell.GetNeighbor(direction);
}
return(length);
}
