/// <summary>
/// Computes the y-values of intersection points with a vertical line. If the line does
/// not intersect the stadium, then both output x-values are set to float.NaN.
/// </summary>
public void VLineIntersection(float xValue, out float miny, out float maxy)
{
List <float> yList = new List <float>(6);
float y1, y2;
// Check the first circle for intersections
(new Circle2D(m_p1, m_r)).VLineIntersection(xValue, out y1, out y2);
if (!float.IsNaN(y1) && !float.IsNaN(y2))
{
// Add intersections to the list
yList.Add(y1);
yList.Add(y2);
}
// Now check the second circle
(new Circle2D(m_p2, m_r)).VLineIntersection(xValue, out y1, out y2);
if (!float.IsNaN(y1) && !float.IsNaN(y2))
{
// Add intersections to the list
yList.Add(y1);
yList.Add(y2);
}
// Now check the first line segment edge
Vector2D perp = Vector2D.Normalize(m_p2 - m_p1).GetPerpendicular();
Vector2D pt = new Vector2D();
if ((new LineSegment2D(m_p1 + (perp * m_r), m_p2 + (perp * m_r))).GetPointWithXValue(xValue, ref pt))
{
yList.Add(pt.Y);
}
// Build the second edge and see if we intersect that too
if ((new LineSegment2D(m_p1 - (perp * m_r), m_p2 - (perp * m_r))).GetPointWithXValue(xValue, ref pt))
{
yList.Add(pt.Y);
}
// If we don't have at least 2 values in the list then we have no intersection
if (yList.Count < 2)
{
miny = float.NaN;
maxy = float.NaN;
return;
}
// Sort the list of intersections so that the first item in the list will be the minimum and the last
// item will be the maximum.
yList.Sort();
// Set intersection x-values
miny = yList[0];
maxy = yList[yList.Count - 1];
}
/// <summary>
/// Computes the x-values of intersection points with a horizontal line. If the line does
/// not intersect the stadium, then both output x-values are set to float.NaN.
/// </summary>
public void HLineIntersection(float yValue, out float minx, out float maxx)
{
List <float> xList = new List <float>(6);
float x1, x2;
(new Circle2D(m_p1, m_r)).HLineIntersection(yValue, out x1, out x2);
if (!float.IsNaN(x1) && !float.IsNaN(x2))
{
// Add intersections to the list
xList.Add(x1);
xList.Add(x2);
}
// Now check the second circle
(new Circle2D(m_p2, m_r)).HLineIntersection(yValue, out x1, out x2);
if (!float.IsNaN(x1) && !float.IsNaN(x2))
{
// Add intersections to the list
xList.Add(x1);
xList.Add(x2);
}
// Now check the first line segment edge
Vector2D perp = Vector2D.Normalize(m_p2 - m_p1).GetPerpendicular();
Vector2D pt = new Vector2D();
if ((new LineSegment2D(m_p1 + (perp * m_r), m_p2 + (perp * m_r))).GetPointWithYValue(yValue, ref pt))
{
xList.Add(pt.X);
}
// Build the second edge and see if we intersect that too
if ((new LineSegment2D(m_p1 - (perp * m_r), m_p2 - (perp * m_r))).GetPointWithYValue(yValue, ref pt))
{
xList.Add(pt.X);
}
// If we don't have at least 2 values in the list then we have no intersection
if (xList.Count < 2)
{
minx = float.NaN;
maxx = float.NaN;
return;
}
// Sort the list of intersections so that the first item in the list will be the minimum and the last
// item will be the maximum.
xList.Sort();
// Set intersection x-values
minx = xList[0];
maxx = xList[xList.Count - 1];
}
/// <summary>
/// Constructs the line from general-form equation coefficients. The line will be normalized
/// internally.
/// </summary>
/// <param name="a">"A" value in the equation Ax+By+C=0</param>
/// <param name="b">"B" value in the equation Ax+By+C=0</param>
/// <param name="c">"C" value in the equation Ax+By+C=0</param>
public NormalizedGeneralLine2D(float a, float b, float c)
{
Vector2D norm = new Vector2D(a, b);
c /= norm.Length;
norm.Normalize();
m_a = norm.X;
m_b = norm.Y;
m_c = c;
}
public Vector2D GetUnitNormal()
{
return(Vector2D.Normalize(new EOFC.Vector2D(m_p1.Y - m_p2.Y, m_p2.X - m_p1.X)));
}
