public Wall CreateWall(Polygon2D area)
{
var w = new Wall();
w.Area = area;
return w;
}
public Corridor CreateCorrdior(Polygon2D area, double floorHeight, double ceilingHeight)
{
var c = new Corridor();
c.Area = area;
c.FloorHeight = floorHeight;
c.CeilingHeight = ceilingHeight;
return c;
}
public Platform CreatePlatform(Polygon2D area, double ceilingHeight, double floorHeight)
{
var c = new Platform();
c.Area = area;
c.FloorHeight = floorHeight;
c.CeilingHeight = ceilingHeight;
return c;
}
// find the type of a specific vertex in a polygon, either Concave or Convex.
public Polygon2DType VertexType(int vertexNo)
{
Polygon2D triangle;
if (vertexNo == 0)
{
triangle =
new Polygon2D(new List<Vector2D>
{ClosedPoints[ClosedPoints.Count - 2], ClosedPoints[0], ClosedPoints[1]});
// the polygon is always closed so the last point is the same as the first
}
else
{
triangle =
new Polygon2D(new List<Vector2D>
{ClosedPoints[vertexNo - 1], ClosedPoints[vertexNo], ClosedPoints[vertexNo + 1]});
}
if (Math.Sign(triangle.Area) == Math.Sign(Area))
return Polygon2DType.Convex;
else
return Polygon2DType.Concave;
}
private static int FindEar(Polygon2D poly)
{
for (int i = 0; i < poly.ClosedPoints.Count - 2; i++)
{
if (poly.VertexType(i + 1) == Polygon2DType.Convex)
{
// get the three points of the triangle we are about to test
Vector2D a = poly.ClosedPoints[i];
Vector2D b = poly.ClosedPoints[i + 1];
Vector2D c = poly.ClosedPoints[i + 2];
bool foundAPointInTheTriangle = false;
// see if any of the other points in the polygon are in this triangle
for (int j = 0; j < poly.Points.Count; j++)
// don't check the last point, which is a duplicate of the first
{
if (j != i && j != i + 1 && j != i + 2 && Intersections.PointInTriangle(poly.ClosedPoints[j], a, b, c))
foundAPointInTheTriangle = true;
}
if (!foundAPointInTheTriangle)
// the middle point of this triangle is convex and none of the other points in the polygon are in this triangle, so it is an ear
return i + 1; // EXITING HERE!
}
}
throw new ApplicationException("Improperly formed polygon");
}
public List<Polygon2D> Triangulate()
{
Polygon2D poly = new Polygon2D(this.Points);
//poly.Points.Reverse();
var triangles = new List<Polygon2D>(); // accumulate the triangles here
// keep clipping ears off of poly until only one triangle remains
while (poly.Points.Count > 3) // if only 3 points are left, we have the final triangle
{
int midvertex = FindEar(poly); // find the middle vertex of the next "ear"
triangles.Add(new Polygon2D(new List<Vector2D>
{
poly.ClosedPoints[midvertex - 1], poly.ClosedPoints[midvertex],
poly.ClosedPoints[midvertex + 1]
}));
// create a new polygon that clips off the ear; i.e., all vertices but midvertex
var newPts = new List<Vector2D>(poly.Points);
newPts.RemoveAt(midvertex); // clip off the ear
poly = new Polygon2D(newPts); // poly now has one less point
}
// only a single triangle remains, so add it to the triangle list
triangles.Add(poly);
return triangles;
}
public static bool PolygonPolygonIntersection(Polygon2D a, Polygon2D b)
{
return
(from line2D in a.Lines
from line in b.Lines
where LineLineIntersection(line2D, line) != null
select line2D).Any();
}
public static List<Vector2D> PolygonLineIntersection(Polygon2D polygon, Line2D intersectLine)
{
return
polygon.Lines.Select(line => LineLineIntersection(line, intersectLine)).Where(point => point != null).
ToList();
}
// this is sloppy as f**k... but should work... rewrite later
public static bool IsPointInPolygon(Polygon2D polygon, Vector2D point)
{
//double minX = polygon.Points[0].X;
//double minY = polygon.Points[0].Y;
//double maxX = polygon.Points[0].X;
//double maxY = polygon.Points[0].Y;
//for (int i = 1; i < polygon.Points.Count; i++)
//{
// if (polygon.Points[i].X < minX)
// minX = polygon.Points[i].X;
// if (polygon.Points[i].Y < minY)
// minY = polygon.Points[i].Y;
// if (polygon.Points[i].X > maxX)
// maxX = polygon.Points[i].X;
// if (polygon.Points[i].Y > maxY)
// maxY = polygon.Points[i].Y;
//}
//var r = new Random();
//var p = new Vector2D();
//while (true)
//{
// var rx = r.NextDouble() * double.MaxValue;
// var ry = r.NextDouble() * double.MaxValue;
// if ((minX <= rx && rx <= maxX) || (minY <= ry && ry <= maxY)) continue;
// p.X = rx;
// p.Y = ry;
// break;
//}
//var q = PolygonLineIntersection(polygon, new Line2D(p, point));
//return q.Count % 2 != 0;
List<Polygon2D> tris = polygon.Triangulate();
foreach (Polygon2D polygon2D in tris)
{
if (PointInTriangle(point, polygon2D.Points[0], polygon2D.Points[1], polygon2D.Points[2]))
return true;
}
return false;
}
// private static int FindLineCircleIntersections(double cx, double cy, double radius,
//Vector2D point1, Vector2D point2)
// {
// double dx, dy, A, B, C, det;
// dx = point2.X - point1.X;
// dy = point2.Y - point1.Y;
// A = dx * dx + dy * dy;
// B = 2 * (dx * (point1.X - cx) + dy * (point1.Y - cy));
// C = (point1.X - cx) * (point1.X - cx) + (point1.Y - cy) * (point1.Y - cy) - radius * radius;
// det = B * B - 4 * A * C;
// if ((A <= 0.0000001) || (det < 0))
// {
// return 0;
// }
// else if (det == 0)
// {
// return 1;
// }
// else
// {
// return 2;
// }
// }
// public static bool CirclePolygonIntersecton(Circle2D c, Polygon2D p)
// {
// foreach (var l in p.Lines)
// {
// var count = FindLineCircleIntersections(c.Point.X, c.Point.Y, c.Radius, l.A, l.B);
// if (count == 2)
// return true;
// else if (count == 1 && IsPointInPolygon(p, c.Point))
// return true;
// }
// if (IsPointInPolygon(p, c.Point))
// return true;
// return false;
// }
public static bool CirclePolygonIntersection(Circle2D c, Polygon2D p)
{
if (IsPointInPolygon(p, c.Point))
return true;
foreach (var l in p.Lines)
{
if (CircleLineIntersection(c, l))
return true;
}
return false;
}
