public bool IsParallel(NormalizedGeneralLine2D line2)
{
// The two lines will be parallel if their normal vectors are the same
// or one is the negative of the other.
return((m_a == line2.m_a && m_b == line2.m_b) ||
(m_a == -line2.m_a && m_b == -line2.m_b));
}
// Checks to see if this line intersects with "line2". True is returned
// if they do intersect. The "ISectPt" is optional and can be NULL, but, if
// provided, it is filled with the point of intersection.
// IMPORTANT: If the two lines are equal then false is returned, not true.
// Do not call for degenerate lines (check with IsDegenerate).
public bool Intersects(NormalizedGeneralLine2D line2, ref EOFC.Vector2D ISectPt)
{
// If the two lines are parallel then they won't intersect
if (IsParallel(line2))
{
return(false);
}
float x, y;
// Handle special case
if (m_a == 0.0f)
{
y = -m_c / m_b;
x = (-line2.m_b * y - line2.m_c) / line2.m_a;
ISectPt = new EOFC.Vector2D(x, y);
return(true);
}
// else
float val1 = (-line2.m_a * m_b) / m_a + line2.m_b;
y = ((line2.m_a * m_c / m_a) - line2.m_c) / val1;
x = (-m_b * y - m_c) / m_a;
ISectPt = new EOFC.Vector2D(x, y);
return(true);
}
public bool Intersects(NormalizedGeneralLine2D line, ref EOFC.Vector2D outISectPt)
{
NormalizedGeneralLine2D thisInfLine = GetInfiniteLine();
EOFC.Vector2D temp = new Vector2D();
if (!thisInfLine.Intersects(line, ref temp))
{
return(false);
}
// The two infinite lines intersect, now see if the intersection point
// is on this segment
if (this.IsPointOnSegment(temp))
{
outISectPt = temp;
return(true);
}
return(false);
}
/// <summary>
/// Gets the point on this line segment with the specified y-value. If no such point
/// exists on the segment then false is returned. Note that if the segment is horizontal,
/// even if it has a y-value of "y", then false is returned.
/// </summary>
public bool GetPointWithYValue(float y, ref EOFC.Vector2D outPt)
{
// If this segment is horizontal, return false.
if (m_p1.Y == m_p2.Y)
{
return(false);
}
NormalizedGeneralLine2D infLine = GetInfiniteLine();
float x = infLine.GetXCoord(y);
EOFC.Vector2D pt = new EOFC.Vector2D(x, y);
if (IsPointOnSegment(pt))
{
outPt.Set(pt);
return(true);
}
return(false);
}
/// <summary>
/// Gets the point on this line segment with the specified x-value. If no such point
/// exists on the segment then false is returned. Note that if the segment is vertical,
/// even if it has a x-value of "x", then false is returned.
/// </summary>
public bool GetPointWithXValue(float x, ref EOFC.Vector2D outPt)
{
// If this segment is vertical, return false.
if (m_p1.X == m_p2.X)
{
return(false);
}
NormalizedGeneralLine2D infLine = GetInfiniteLine();
float y = infLine.GetYCoord(x);
EOFC.Vector2D pt = new EOFC.Vector2D(x, y);
if (IsPointOnSegment(pt))
{
outPt.Set(pt);
return(true);
}
return(false);
}
public NormalizedGeneralLine2D(NormalizedGeneralLine2D copyme)
{
this.m_a = copyme.m_a;
this.m_b = copyme.m_b;
this.m_c = copyme.m_c;
}
public bool Equals(NormalizedGeneralLine2D other)
{
return(this.m_a == other.m_a && this.m_b == other.m_b && this.m_c == other.m_c);
}
