///<summary>
///there's no need to do an accurate (and expensive) circle versus
///rectangle intersection test. Instead we'll just test the bounding box
///of the given circle with the rectangle.
///</summary>
///<param name="entityCenter"></param>
///<param name="entityRadius"></param>
///<returns></returns>
public override bool IsTouching(Vector2 entityCenter, float entityRadius)
{
InvertedAABBox2D box =
new InvertedAABBox2D(
new Vector2(
entityCenter.X - entityRadius,
entityCenter.Y - entityRadius),
new Vector2(
entityCenter.X + entityRadius,
entityCenter.Y + entityRadius));
return box.IsOverlappedWith(Rectangle);
}
//returns
///<summary>
///Tests if the bounding box described by other intersects with this one
///</summary>
///<param name="other"></param>
///<returns>
///true if the bounding box described by other intersects with this one
///</returns>
public bool IsOverlappedWith(InvertedAABBox2D other)
{
return !((other.Top > Bottom) ||
(other.Bottom < Top) ||
(other.Left > Right) ||
(other.Right < Left));
}
///<summary>
///constructor
///</summary>
///<param name="topLeft"></param>
///<param name="bottomRight"></param>
public Cell(Vector2 topLeft, Vector2 bottomRight)
{
_members = new List<NavGraphNode>();
_boundingBox = new InvertedAABBox2D(topLeft, bottomRight);
}
///<summary>
///This must be called to create the list of neighbors. This method
///examines each cell within range of the target, If the cells contain
///entities then they are tested to see if they are situated within the
///target's neighborhood region. If they are they are added to
///neighbor list
///</summary>
///<param name="targetPos"></param>
///<param name="queryRadius"></param>
public void CalculateNeighbors(Vector2 targetPos, float queryRadius)
{
//create an iterator and set it to the beginning of the
//neighbor list
int curNbor = 0;
//create the query box that is the bounding box of the
//target's query area
InvertedAABBox2D queryBox =
new InvertedAABBox2D(
targetPos - new Vector2(queryRadius, queryRadius),
targetPos + new Vector2(queryRadius, queryRadius));
//iterate through each cell and test to see if its bounding box
//overlaps with the query box. If it does and it also contains
//entities then make further proximity tests.
foreach (Cell curCell in Cells)
{
//test to see if this cell contains members and if it overlaps
//the query box
if (!curCell.BoundingBox.IsOverlappedWith(queryBox) ||
curCell.Members.Count <= 0)
continue;
//add any entities found within query radius to the neighbor list
foreach (NavGraphNode curNode in curCell.Members)
{
if (GraphNode.IsInvalidIndex(curNode.Index))
continue;
if (Vector2.DistanceSquared(curNode.Position, targetPos) >=
queryRadius*queryRadius)
continue;
Neighbors[curNbor] = curNode;
curNbor++;
}
}
//mark the end of the list with a null.
Neighbors[curNbor] = null;
}
///<summary>
///constructor
///</summary>
///<param name="topLeft"></param>
///<param name="bottomRight"></param>
public TriggerRegionRectangle(Vector2 topLeft, Vector2 bottomRight)
{
_rectangle = new InvertedAABBox2D(topLeft, bottomRight);
}
