public static bool Intersects(Ray2LR a, Segment2LR b)
{
if (a.direction.IsZero)
{
return(b.Contains(a.origin));
}
Vector2LR v = new Vector2LR(-a.Direction.Y, a.Direction.X);
if (Vector2LR.DotProduct(b.Start - a.Origin, v).IsPositive == Vector2LR.DotProduct(b.End - a.Origin, v).IsPositive)
{
return(false);
}
if (b.Start == b.End)
{
return(a.Contains(b.Start));
}
Vector2LR delta = b.GetDelta();
LongRational longRational1 = a.Direction.X * delta.Y - a.Direction.Y * delta.X;
if (longRational1.IsZero)
{
return(false);
}
Vector2LR u = b.Start - a.Origin;
LongRational longRational2 = Vector2LR.CrossProduct(u, delta);
if (longRational1.IsPositive)
{
if (longRational2.IsNegative)
{
return(false);
}
}
else if (longRational2.IsPositive)
{
return(false);
}
LongRational longRational3 = Vector2LR.CrossProduct(u, a.Direction);
if (longRational1.IsPositive)
{
if (longRational3.IsNegative || longRational3 > longRational1)
{
return(false);
}
}
else if (longRational3.IsPositive || longRational3 < longRational1)
{
return(false);
}
LongRational longRational4 = longRational3 / longRational1;
LongRational longRational5 = longRational2 / longRational1;
return(true);
}
public static bool GetIntersectionCoefficients(
Ray2LR a,
Segment2LR b,
out LongRational?p,
out LongRational?q,
out bool areParallel)
{
if (a.direction.IsZero)
{
areParallel = false;
p = new LongRational?();
bool flag;
if (flag = b.Contains(a.origin))
{
Vector2LR delta = b.GetDelta();
q = new LongRational?(Vector2LR.DotProduct(a.origin - b.Start, delta) / delta.GetLengthSquared());
}
else
{
q = new LongRational?();
}
return(flag);
}
Vector2LR v = new Vector2LR(-a.direction.Y, a.direction.X);
Vector2LR u = b.Start - a.Origin;
LongRational longRational1 = Vector2LR.DotProduct(u, v);
LongRational longRational2 = Vector2LR.DotProduct(b.End - a.Origin, v);
if (longRational1.IsPositive && longRational2.IsPositive || longRational1.IsNegative && longRational2.IsNegative)
{
p = new LongRational?();
q = new LongRational?();
areParallel = false;
return(false);
}
Vector2LR delta1 = b.GetDelta();
if (delta1.IsZero)
{
areParallel = false;
p = new LongRational?(Vector2LR.DotProduct(u, a.direction) / a.direction.GetLengthSquared());
q = new LongRational?(LongRational.Zero);
return(true);
}
LongRational longRational3 = a.Direction.X * delta1.Y - a.Direction.Y * delta1.X;
if (longRational3.IsZero)
{
p = new LongRational?();
q = new LongRational?();
areParallel = true;
return(true);
}
areParallel = false;
LongRational longRational4 = Vector2LR.CrossProduct(u, delta1);
if (longRational3.IsPositive)
{
if (longRational4.IsNegative)
{
p = new LongRational?();
q = new LongRational?();
return(false);
}
}
else if (longRational4.IsPositive)
{
p = new LongRational?();
q = new LongRational?();
return(false);
}
LongRational longRational5 = Vector2LR.CrossProduct(u, a.Direction);
if (longRational3.IsPositive)
{
if (longRational5.IsNegative || longRational5 > longRational3)
{
p = new LongRational?();
q = new LongRational?();
return(false);
}
}
else if (longRational5.IsPositive || longRational5 < longRational3)
{
p = new LongRational?();
q = new LongRational?();
return(false);
}
p = new LongRational?(longRational4 / longRational3);
q = new LongRational?(longRational5 / longRational3);
return(true);
}
