void TriangulateWithRiverBeginOrEnd(HexDirection direction, HexCell cell)
{
var center = cell.Center;
var closerEdge = cell.Edges[(int)direction];
if (cell.HasRiverThroughEdge(direction.Next()))
{
if (cell.HasRiverThroughEdge(direction.Previous()))
{
center += HexMetrics.GetSolidEdgeMiddle(direction) * (HexMetrics.InnerToOuter * 0.5f);
}
else if (cell.HasRiverThroughEdge(direction.Previous2()))
{
center += HexMetrics.GetLeftSolidCorner(direction) * 0.25f;
}
}
else if (cell.HasRiverThroughEdge(direction.Previous()) && cell.HasRiverThroughEdge(direction.Next2()))
{
center += HexMetrics.GetRightSolidCorner(direction) * 0.25f;
}
var m = new EdgeVertices(Vector3.Lerp(center, closerEdge.V1, 0.5f), Vector3.Lerp(center, closerEdge.V5, 0.5f));
m.V3.y = closerEdge.V3.y; // reassign middle verticle height as it is ommited in the calculation above
TriangulateEdgeStrip(m, cell.Color, closerEdge, cell.Color);
TriangulateEdgeFan(center, m, cell.Color);
// river segments are added only if the current segment is not under water
if (!cell.IsUnderwater)
{
bool reversed = cell.HasIncomingRiver;
// outer circle of the hex
TriangulateRiverQuadUnperturbed(m.V2, m.V4, closerEdge.V2, closerEdge.V4, cell.RiverSurfaceY, 0.6f, reversed);
// end (or start) triangle
center.y = m.V2.y = m.V4.y = cell.RiverSurfaceY;
Rivers.AddTriangleUnperturbed(center, m.V2, m.V4);
if (reversed)
{
Rivers.AddTriangleUV(new Vector2(0.5f, 0.4f), new Vector2(1f, 0.2f), new Vector2(0f, 0.2f));
}
else
{
Rivers.AddTriangleUV(new Vector2(0.5f, 0.4f), new Vector2(0f, 0.6f), new Vector2(1f, 0.6f));
}
}
}