/** Finds the minimum bounding area containing all points in <param name="points">points</param>,
* where the face of each point faces <param name="center">center</param>. */
private List<Vector3> facePointArea(List<Vector3> points, Vector3 center)
{
List<WaterEdge> edges = new List<WaterEdge>();
for (int i = 0; i < points.Count; i++ )
{
edges.Add(new WaterEdge(points[i], points[(i+1)%points.Count], new List<Vector3>()));
}
for (int i = 0; i < edges.Count; i++)
{
if (!edgeFacesPoint(edges[i], center))
{
//for the other winding order
//int prev = (i + edges.Count - 1) % edges.Count;
//edges[prev] = new WaterEdge(edges[prev].NodeA, edges[i].NodeB, new List<Vector3>());
//edges.RemoveAt(i);
//i = (i + edges.Count - 2) % edges.Count;
//i -= 2;
//if (i < 0) i = 0;
int next = (i + 1) % edges.Count;
edges[i] = new WaterEdge(edges[i].NodeA, edges[next].NodeB, new List<Vector3>());
edges.RemoveAt(next);
i--;
}
}
List<Vector3> boundPoits = new List<Vector3>(edges.Count);
for (int i = 0; i < edges.Count; i++) {
boundPoits.Add(edges[i].NodeA);
}
return boundPoits;
}
/** Finds the minimum bounding convex area containing all points in <param name="points">points</param>. */
/* NOTE: only works if xMin, xMax, yMin and yMax are unique! */
private List<Vector3> minimumConvexArea(List<Vector3> points, List<Vector3> initialPoints, Vector3 center)
{
List<Vector3> distSortedPoints = new List<Vector3>(points);
distSortedPoints.Sort(
delegate(Vector3 v1, Vector3 v2) {
return (int) (Vector3.DistanceSquared(center, v1) - Vector3.DistanceSquared(center, v2));
}
);
List<WaterEdge> bounds = new List<WaterEdge>();
for (int i = 0; i < initialPoints.Count; i++)
{
int next = (i + 1) % initialPoints.Count;
bounds.Add(new WaterEdge(initialPoints[i], initialPoints[next], isClosed(points, center, initialPoints[i], initialPoints[next])));
}
int nextSort = 0;
int firstOpen = 0;
while (firstOpen < bounds.Count) {
Vector3 next = distSortedPoints[nextSort++];
for (int i = firstOpen; i < bounds.Count; i++) {
if (bounds[i].isOutside(next)) {
WaterEdge edgeA = new WaterEdge(bounds[i].NodeA, next, isClosed(points, center, bounds[i].NodeA, next));
WaterEdge edgeB = new WaterEdge(next, bounds[i].NodeB, isClosed(points, center, next, bounds[i].NodeB));
bounds.Remove(bounds[i]);
bounds.Insert(i, edgeB);
bounds.Insert(i, edgeA);
if (i == firstOpen) {
while (firstOpen < bounds.Count && !bounds[firstOpen].Closed) firstOpen++;
}
break;
}
}
}
List<Vector3> boundPoits = new List<Vector3>(bounds.Count);
for (int i = 0; i < bounds.Count; i++) {
boundPoits.Add(bounds[i].NodeA);
}
return boundPoits;
}
private bool edgeFacesPoint(WaterEdge edge, Vector3 point)
{
Vector2 n = Vector2.Normalize(new Vector2(edge.NodeA.X - edge.NodeB.X, edge.NodeA.Y - edge.NodeB.Y));
Vector2 v = new Vector2(point.X - edge.NodeA.X, point.Y - edge.NodeA.Y);
float dist = Vector2.Dot(new Vector2(-n.Y, n.X), v);
//if (dist <= 0) Console.WriteLine("No Face!");
return (dist > 0);
}
