public float DistanceTo(ref CCPoint vector, out Segment connectingSegment)
{
float segmentLength = (float)this.GetLength();
CCPoint normalizedLine = new CCPoint(
(float)(Point2.X - Point1.X) / segmentLength,
(float)(Point2.Y - Point1.Y) / segmentLength);
CCPoint pointVector = new CCPoint((float)(vector.X - Point1.X), (float)(vector.Y - Point1.Y));
float length = CCPoint.Dot(pointVector, normalizedLine);
connectingSegment = new Segment ();
if (length < 0)
{
connectingSegment.Point1 = vector;
connectingSegment.Point2 = Point1;
return (float) connectingSegment.GetLength();
}
else if (length > segmentLength)
{
connectingSegment.Point1 = vector;
connectingSegment.Point2 = Point2;
return (float) connectingSegment.GetLength();
}
else
{
connectingSegment.Point1 = vector;
connectingSegment.Point2 = new CCPoint(Point1.X + length * normalizedLine.X,
Point1.Y + length * normalizedLine.Y);
return (float)connectingSegment.GetLength();
}
}
public bool CollideAgainst(Circle circle)
{
UpdateAbsolutePoints ();
// This method will test the following things:
// * Is the circle's center inside the polygon?
// * Are any of the polygon's points inside the circle?
// * Is the circle within Radius distance from any of the polygon's edges?
// Of course none of this is done if the radius check fails
if ((circle.Radius + boundingRadius) * (circle.Radius + boundingRadius) >
(circle.PositionX - PositionX) * (circle.Position.X - Position.X) +
(circle.PositionY - PositionY) * (circle.Position.Y - Position.Y))
{
// First see if the circle is inside the polygon.
if (IsPointInside(circle.PositionWorldspace.X, circle.PositionWorldspace.Y))
{
LastCollisionPoint.X = circle.Position.X;
LastCollisionPoint.Y = circle.Position.Y;
return true;
}
int i;
// Next see if any of the Polygon's points are inside the circle
for (i = 0; i < absolutePoints.Length; i++)
{
if (circle.IsPointInside(absolutePoints[i]))
{
LastCollisionPoint.X = absolutePoints[i].X;
LastCollisionPoint.Y = absolutePoints[i].Y;
return true;
}
}
int k;
Segment s1 = new Segment();
Segment s2 = new Segment();
// Next check if the circle is within Radius units of any segment.
for (i = 0; i < absolutePoints.Length; i++)
{
k = i + 1 < absolutePoints.Length ? i + 1 : 0;
s1.Point1 = absolutePoints [i];
s1.Point2 = absolutePoints[k];
var position = circle.PositionWorldspace;
var segmentDistance = s1.DistanceTo (ref position, out s2);
if (segmentDistance < circle.Radius)
{
LastCollisionPoint.X = s2.Point2.X;
LastCollisionPoint.Y = s2.Point2.Y;
return true;
}
}
}
return false;
}
public static CCPoint VectorFrom(float x, float y, CCPoint[] vertices, out int pointIndexBefore)
{
pointIndexBefore = -1;
double minDistance = double.PositiveInfinity;
double tempMinDistance;
CCPoint vectorToReturn = new CCPoint();
if (vertices.Length == 1)
{
return new CCPoint(
vertices[0].X - x,
vertices[0].Y - y);
}
Segment connectingSegment = new Segment();
Segment segment = new Segment();
for (int i = 0; i < vertices.Length - 1; i++)
{
int afterI = i + 1;
segment.Point1 = new CCPoint(vertices[i].X, vertices[i].Y);
segment.Point2 = new CCPoint(vertices[afterI].X, vertices[afterI].Y);
var point = new CCPoint (x, y);
tempMinDistance = segment.DistanceTo(ref point, out connectingSegment);
if (tempMinDistance < minDistance)
{
pointIndexBefore = i;
minDistance = tempMinDistance;
vectorToReturn = new CCPoint(
connectingSegment.Point2.X - connectingSegment.Point1.X,
connectingSegment.Point2.Y - connectingSegment.Point1.Y);
}
}
return vectorToReturn;
}
