public Node FindUnguardedPoint(ArrayList guards)
{
ArrayList wallsNotVisible = (ArrayList)_walls.Clone();
foreach (Node guard in guards)
{
ArrayList visibleVertices = new ArrayList();
ArrayList tempWallsNotVisible = (ArrayList)wallsNotVisible.Clone();
foreach (Wall wall in tempWallsNotVisible)
{
if (wall != null)
{
bool fromVisible = false, toVisible = false;
if (IsVisible(guard, wall.From))
{
visibleVertices.Add(wall.From);
wall.TemporaryViewablePoint = wall.From;
fromVisible = true;
}
if (IsVisible(guard, wall.To))
{
wall.TemporaryViewablePoint = wall.To;
toVisible = true;
}
if (fromVisible && toVisible)
{
wall.TemporaryViewablePoint = null;
//wall.VisibleSegments.Add(new Segment(wall.From, wall.To));
wallsNotVisible.Remove(wall);
}
}
}
foreach (Node vertex in visibleVertices)
{
if (vertex.Type == VertexType.Special)
{
decimal dy = guard.Y - vertex.Y;
decimal dx = guard.X - vertex.X;
decimal e = (decimal)0.0000000001;
Node nearNode1, nearNode2, distantNode;
if (Equals(guard.X, vertex.X))
{
decimal diffY = 50 * dy;
if (guard.Y < vertex.Y)
{
nearNode1 = new Node(guard.X, guard.Y + 5 * e);
nearNode2 = new Node(vertex.X, vertex.Y + 2 * e);
distantNode = new Node(vertex.X, vertex.Y + diffY);
}
else
{
nearNode1 = new Node(guard.X, guard.Y - 5 * e);
nearNode2 = new Node(vertex.X, vertex.Y - e);
distantNode = new Node(vertex.X, vertex.Y - diffY);
}
}
else
{
decimal deltaX = e * dx;
decimal deltaY = e * dy;
decimal diffX = 50 * dx;
decimal diffY = 50 * dy;
if (guard.X < vertex.X)
{
nearNode1 = new Node(guard.X + deltaX, guard.Y + 5 * deltaY);
nearNode2 = new Node(vertex.X + deltaX, vertex.Y + deltaY);
distantNode = new Node(vertex.X + diffX, vertex.Y + diffY);
}
else
{
nearNode1 = new Node(guard.X - deltaX, guard.Y - 5 * deltaY);
nearNode2 = new Node(vertex.X - deltaX, vertex.Y - deltaY);
distantNode = new Node(vertex.X - diffX, vertex.Y - diffY);
}
}
if (PointInPolygon(nearNode2) && PointInPolygon(nearNode1))
{
Segment extendedLine = new Segment(new Node(guard.X, guard.Y), distantNode);
ArrayList intersectionList = new ArrayList();
ArrayList intersectionWallList = new ArrayList();
foreach (Wall wall in _walls)
{
if (wall != null)
{
Node intersection = Intersection(extendedLine, wall.From, wall.To);
if (intersection != null && !Equals(intersection, vertex))
{
intersectionList.Add(intersection);
intersectionWallList.Add(wall);
}
}
}
Node nearestIntersection = GetNearestIntersection(intersectionList);
if (nearestIntersection != null)
{
Wall wall = intersectionWallList[intersectionList.IndexOf(nearestIntersection)] as Wall;
if (wall != null)
{
if (wall.TemporaryViewablePoint == null)
{
wall.TemporaryViewablePoint = nearestIntersection;
}
else
{
Wall[] splitWall = SplitWall(wall, wall.TemporaryViewablePoint, nearestIntersection);
ArrayList tempWallsNotVisible2 = (ArrayList)wallsNotVisible.Clone();
foreach (Wall wallNotVisible in tempWallsNotVisible2)
{
if (IsOnLine(wallNotVisible.From, wallNotVisible.To, nearestIntersection) &&
!Equals(nearestIntersection, wall.From) && !Equals(nearestIntersection, wall.To))
{
wallsNotVisible.Remove(wall);
}
}
wall.TemporaryViewablePoint = null;
wallsNotVisible.Remove(wall);
wallsNotVisible.Add(splitWall[0]);
if (splitWall[1] != null) wallsNotVisible.Add(splitWall[1]);
}
}
}
}
}
}
foreach (Wall wall in wallsNotVisible)
{
if (wall != null)
{
wall.TemporaryViewablePoint = null;
}
}
}
if (wallsNotVisible.Count == 0)
{
return new Node(100000, 100000);
}
foreach (Wall wall in wallsNotVisible)
{
if (wall != null)
{
Wall unguardedWall = (Wall)wallsNotVisible[0];
decimal x = (unguardedWall.From.X + unguardedWall.To.X) / 2;
decimal y = (unguardedWall.From.Y + unguardedWall.To.Y) / 2;
return new Node(x, y);
}
}
return new Node(100000, 100000);
}
private bool IsParallel(Segment segment1, Segment segment2)
{
bool vertical1 = false, vertical2 = false;
decimal gradient1 = 0, gradient2 = 0;
try
{
gradient1 = (segment1.To.Y - segment1.From.Y) / (segment1.To.X - segment1.From.X);
}
catch (Exception)
{
vertical1 = true;
}
try
{
gradient2 = (segment2.To.Y - segment2.From.Y) / (segment2.To.X - segment2.From.X);
}
catch (Exception)
{
vertical2 = true;
}
if (vertical1 && vertical2)
{
return true;
}
if (vertical1 || vertical2)
{
return false;
}
if (Equals(gradient1, gradient2))
{
return true;
}
return false;
}
// TODO: Finish this function
private Node Intersection(Segment segment1, Node from, Node to)
{
if (Equals(segment1.From, from) || Equals(segment1.From, to)
|| Equals(segment1.To, from) || Equals(segment1.To, to)
|| IsParallel(segment1, new Segment(from, to)))
{
return null;
}
decimal segment1X = segment1.From.X, segment1Y = segment1.From.Y;
decimal segment1Dx = segment1.To.X - segment1.From.X, segment1Dy = segment1.To.Y - segment1.From.Y;
decimal segment2X = to.X, segment2Y = to.Y;
decimal segment2Dx = from.X - to.X, segment2Dy = from.Y - to.Y;
if (Equals(segment1Dx, 0) && (from.X < segment1Y && to.X > segment1Y
|| from.X > segment1Y && to.X < segment1Y)) // Handle segment 1 is vertical
{
if (Equals(segment1Dx, segment2Dx))
{
return null;
}
decimal gradient = segment2Dy / segment2Dx;
Node node = new Node(segment1Y, segment1Y * gradient);
if ((node.Y < segment1.From.Y && node.Y < segment1.To.Y)
|| (node.Y > segment1.From.Y && node.Y > segment1.To.Y))
{
return null;
}
return node;
}
if (Equals(segment2Dx, 0) && (from.X < segment2Y && to.X > segment2Y
|| from.X > segment2Y && to.X < segment2Y)) // Handle segment 2 is vertical
{
if (Equals(segment1Dx, segment2Dx))
{
return null;
}
decimal gradient = segment1Dy / segment1Dx;
Node node = new Node(segment2Y, segment2Y * gradient);
if ((node.Y < from.Y && node.Y < to.Y)
|| (node.Y > from.Y && node.Y > to.Y))
{
return null;
}
return node;
}
if (!Equals(segment2Dx*segment1Dy, segment2Dy*segment1Dx))
{
try
{
decimal t2 = (segment1Dx*(segment2Y - segment1Y) + segment1Dy*(segment1X - segment2X))/
(segment2Dx*segment1Dy - segment2Dy*segment1Dx);
decimal t1 = (segment2X + segment2Dx*t2 - segment1X)/segment1Dx;
if (t2 <= 1 && t2 >= 0 && t1 >= 0 && t1 <= 1)
{
Node node = new Node(segment1X + segment1Dx*t1, segment1Y + segment1Dy*t1);
/*if (node == from || node == to) // TODO: If intersection is with a concave-inside vertex, ignore it (as above) - return null
{
if ((Math.Atan2((double)nextDy, (double)nextDx) >= 0 && Math.Atan2((double)previousDy, (double)previousDx) >= 0)
|| (Math.Atan2((double)nextDy, (double)nextDx) <= 0 && Math.Atan2((double)previousDy, (double)previousDx) <= 0))
{ }
else { return null; }
}*/
return node;
}
}
catch (Exception e)
{
Console.Write(e);
}
}
return null;
}
