public static List <Line> setConcaveHull(double concavity, int scaleFactor)
{
/* Run setConvHull before!
* Concavity is a value used to restrict the concave angles
* It can go from -1 (no concavity) to 1 (extreme concavity)
* Avoid concavity == 1 if you don't want 0º angles
* */
bool aLineWasDividedInTheIteration;
hull_concave_edges.AddRange(hull_edges);
do
{
aLineWasDividedInTheIteration = false;
for (int linePositionInHull = 0; linePositionInHull < hull_concave_edges.Count && !aLineWasDividedInTheIteration; linePositionInHull++)
{
Line line = hull_concave_edges[linePositionInHull];
List <Node> nearbyPoints = HullFunctions.getNearbyPoints(line, unused_nodes, scaleFactor);
List <Line> dividedLine = HullFunctions.getDividedLine(line, nearbyPoints, hull_concave_edges, concavity);
if (dividedLine.Count > 0) // Line divided!
{
aLineWasDividedInTheIteration = true;
unused_nodes.Remove(unused_nodes.Where(n => n.id == dividedLine[0].nodes[1].id).FirstOrDefault()); // Middlepoint no longer free
hull_concave_edges.AddRange(dividedLine);
hull_concave_edges.RemoveAt(linePositionInHull); // Divided line no longer exists
}
}
hull_concave_edges = hull_concave_edges.OrderByDescending(a => Line.getLength(a.nodes[0], a.nodes[1])).ToList();
} while (aLineWasDividedInTheIteration);
return(hull_concave_edges);
}
public static void setConcaveHull(decimal concavity, int scaleFactor, bool isSquareGrid)
{
/* Run setConvHull before!
* Concavity is a value used to restrict the concave angles
* it can go from -1 to 1 (it wont crash if you go further)
* */
Hull.scaleFactor = scaleFactor;
hull_concave_edges = new List <Line>(hull_edges.OrderByDescending(a => Line.getLength(a.nodes[0], a.nodes[1])).ToList());
Line selected_edge;
List <Line> aux = new List <Line>();;
int list_original_size;
int count = 0;
bool listIsModified = false;
do
{
listIsModified = false;
count = 0;
list_original_size = hull_concave_edges.Count;
while (count < list_original_size)
{
selected_edge = hull_concave_edges[0];
hull_concave_edges.RemoveAt(0);
aux = new List <Line>();
if (!selected_edge.isChecked)
{
List <Node> nearby_points = HullFunctions.getNearbyPoints(selected_edge, unused_nodes, Hull.scaleFactor);
aux.AddRange(HullFunctions.setConcave(selected_edge, nearby_points, hull_concave_edges, concavity, isSquareGrid));
listIsModified = listIsModified || (aux.Count > 1);
if (aux.Count > 1)
{
foreach (Node node in aux[0].nodes)
{
if (unused_nodes.Find(a => a.id == node.id) != null)
{
unused_nodes.Remove(unused_nodes.Where(a => a.id == node.id).First());
}
}
}
else
{
aux[0].isChecked = true;
}
}
else
{
aux.Add(selected_edge);
}
hull_concave_edges.AddRange(aux);
count++;
}
hull_concave_edges = hull_concave_edges.OrderByDescending(a => Line.getLength(a.nodes[0], a.nodes[1])).ToList();
list_original_size = hull_concave_edges.Count;
} while (listIsModified);
}
public static bool tangentToHull(Line line_treated, Node node, decimal cos1, decimal cos2, List <Line> concave_hull)
{
/* A new middlepoint could (rarely) make a segment that's tangent to the hull.
* This method detects these situations
* I suggest turning this method of if you are not using square grids or if you have a high dot density
* */
bool isTangent = false;
decimal current_cos1;
decimal current_cos2;
double edge_length;
List <int> nodes_searched = new List <int>();
Line line;
Node node_in_hull;
int count_line = 0;
int count_node = 0;
edge_length = Line.getLength(node, line_treated.nodes[0]) + Line.getLength(node, line_treated.nodes[1]);
while (!isTangent && count_line < concave_hull.Count)
{
line = concave_hull[count_line];
while (!isTangent && count_node < 2)
{
node_in_hull = line.nodes[count_node];
if (!nodes_searched.Contains(node_in_hull.id))
{
if (node_in_hull.id != line_treated.nodes[0].id && node_in_hull.id != line_treated.nodes[1].id)
{
current_cos1 = getCos(node_in_hull, line_treated.nodes[0], line_treated.nodes[1]);
current_cos2 = getCos(node_in_hull, line_treated.nodes[1], line_treated.nodes[0]);
if (current_cos1 == cos1 || current_cos2 == cos2)
{
isTangent = (Line.getLength(node_in_hull, line_treated.nodes[0]) + Line.getLength(node_in_hull, line_treated.nodes[1]) < edge_length);
}
}
}
nodes_searched.Add(node_in_hull.id);
count_node++;
}
count_node = 0;
count_line++;
}
return(isTangent);
}
