public virtual void MoveTo(PointFP point)
{
if (!started)
{
startPoint.Reset(point);
started = true;
}
currPoint.Reset(point);
}
public LineFP GetHeadOutline(int ff_rad)
{
PointFP p = new PointFP(P1.X - P2.X, P1.Y - P2.Y);
int len = Length;
p.Reset(MathFP.Div(-p.Y, len), MathFP.Div(p.X, len));
p.Reset(MathFP.Mul(p.X, ff_rad), MathFP.Mul(p.Y, ff_rad));
return(new LineFP(P1.X - p.X, P1.Y - p.Y, P1.X + p.X, P1.Y + p.Y));
}
public LineFP GetTailOutline(int ff_rad)
{
PointFP c = Center;
PointFP p = new PointFP(P2.X - c.X, P2.Y - c.Y);
p.Reset(p.Y, -p.X);
int dis = PointFP.Distance(PointFP.Origin, p);
if (dis == 0)
{
dis = 1;
}
p.Reset(MathFP.Div(MathFP.Mul(p.X, ff_rad), dis), MathFP.Div(MathFP.Mul(p.Y, ff_rad), dis));
return(new LineFP(P2.X - p.X, P2.Y - p.Y, P2.X + p.X, P2.Y + p.Y));
}
public void Reset(int ff_x1, int ff_y1, int ff_x2, int ff_y2)
{
P1.Reset(ff_x1, ff_y1);
P2.Reset(ff_x2, ff_y2);
}
public static bool Intersects(LineFP l1, LineFP l2, PointFP intersection)
{
int x = SingleFP.NaN;
int y = SingleFP.NaN;
if (intersection != null)
{
intersection.Reset(x, y);
}
int ax0 = l1.P1.X;
int ax1 = l1.P2.X;
int ay0 = l1.P1.Y;
int ay1 = l1.P2.Y;
int bx0 = l2.P1.X;
int bx1 = l2.P2.X;
int by0 = l2.P1.Y;
int by1 = l2.P2.Y;
int adx = (ax1 - ax0);
int ady = (ay1 - ay0);
int bdx = (bx1 - bx0);
int bdy = (by1 - by0);
if (IsZero(adx) && IsZero(bdx))
{
return(IsEqual(ax0, bx0));
}
else if (IsZero(ady) && IsZero(bdy))
{
return(IsEqual(ay0, by0));
}
else if (IsZero(adx))
{
// A vertical
x = ax0;
y = IsZero(bdy)?by0:MathFP.Mul(MathFP.Div(bdy, bdx), x - bx0) + by0;
}
else if (IsZero(bdx))
{
// B vertical
x = bx0;
y = IsZero(ady)?ay0:MathFP.Mul(MathFP.Div(ady, adx), x - ax0) + ay0;
}
else if (IsZero(ady))
{
y = ay0;
x = MathFP.Mul(MathFP.Div(bdx, bdy), y - by0) + bx0;
}
else if (IsZero(bdy))
{
y = by0;
x = MathFP.Mul(MathFP.Div(adx, ady), y - ay0) + ax0;
}
else
{
int xma = MathFP.Div(ady, adx); // slope segment A
int xba = ay0 - (MathFP.Mul(ax0, xma)); // y intercept of segment A
int xmb = MathFP.Div(bdy, bdx); // slope segment B
int xbb = by0 - (MathFP.Mul(bx0, xmb)); // y intercept of segment B
// parallel lines?
if (xma == xmb)
{
// Need trig functions
return(xba == xbb);
}
else
{
// Calculate points of intersection
// At the intersection of line segment A and B, XA=XB=XINT and YA=YB=YINT
x = MathFP.Div((xbb - xba), (xma - xmb));
y = (MathFP.Mul(xma, x)) + xba;
}
}
// After the point or points of intersection are calculated, each
// solution must be checked to ensure that the point of intersection lies
// on line segment A and B.
int minxa = MathFP.Min(ax0, ax1);
int maxxa = MathFP.Max(ax0, ax1);
int minya = MathFP.Min(ay0, ay1);
int maxya = MathFP.Max(ay0, ay1);
int minxb = MathFP.Min(bx0, bx1);
int maxxb = MathFP.Max(bx0, bx1);
int minyb = MathFP.Min(by0, by1);
int maxyb = MathFP.Max(by0, by1);
if (intersection != null)
{
intersection.Reset(x, y);
}
return((x >= minxa) && (x <= maxxa) && (y >= minya) && (y <= maxya) && (x >= minxb) && (x <= maxxb) && (y >= minyb) && (y <= maxyb));
}
