bool FloatPolygon::containsEvenOdd(const FloatPoint& point) const
{
unsigned crossingCount = 0;
for (unsigned i = 0; i < numberOfEdges(); ++i) {
const FloatPoint& vertex1 = edgeAt(i).vertex1();
const FloatPoint& vertex2 = edgeAt(i).vertex2();
if (isPointOnLineSegment(vertex1, vertex2, point))
return true;
if ((vertex1.y() <= point.y() && vertex2.y() > point.y()) || (vertex1.y() > point.y() && vertex2.y() <= point.y())) {
float vt = (point.y() - vertex1.y()) / (vertex2.y() - vertex1.y());
if (point.x() < vertex1.x() + vt * (vertex2.x() - vertex1.x()))
++crossingCount;
}
}
return crossingCount & 1;
}
bool FloatPolygon::containsNonZero(const FloatPoint& point) const
{
int windingNumber = 0;
for (unsigned i = 0; i < numberOfEdges(); ++i) {
const FloatPoint& vertex1 = edgeAt(i).vertex1();
const FloatPoint& vertex2 = edgeAt(i).vertex2();
if (isPointOnLineSegment(vertex1, vertex2, point))
return true;
if (vertex2.y() < point.y()) {
if ((vertex1.y() > point.y()) && (leftSide(vertex1, vertex2, point) > 0))
++windingNumber;
} else if (vertex2.y() > point.y()) {
if ((vertex1.y() <= point.y()) && (leftSide(vertex1, vertex2, point) < 0))
--windingNumber;
}
}
return windingNumber;
}
/*!
* @brief returns the intersection of 2 line segments in "inter". if there is more than 1 intersection, the 2nd point is
* returned in "intIfLine"
* @return 0 if lines do not intersect
* 1 if lines intersect in exactly one place
* 2 if lines intersect in more than one place
*****************************************************************************/
int RecLineSegment2D::getIntersection(const RecLineSegment2D& l2,
RecPoint2D& inter,
RecPoint2D& intIfLine) const
{
int numInt=0;
double x1, x2, x3, x4;
double y1, y2, y3, y4;
double n1, n2, d;
double u1, u2;
double tol = 1.0e-25;
/*
* set up some variables
*/
x1 = p1_.x;
x2 = p2_.x;
x3 = l2.p1_.x;
x4 = l2.p2_.x;
y1 = p1_.y;
y2 = p2_.y;
y3 = l2.p1_.y;
y4 = l2.p2_.y;
/*
* bounding box test
*/
if (MAX(x1, x2) < MIN(x3, x4) || MAX(x3, x4) < MIN(x1, x2)) {
return 0;
}
if (MAX(y1, y2) < MIN(y3, y4) || MAX(y3, y4) < MIN(y1, y2)) {
return 0;
}
/*
* set up some variables
*/
n1 = (x4-x3)*(y1-y3)-(y4-y3)*(x1-x3);
n2 = (x2-x1)*(y1-y3)-(y2-y1)*(x1-x3);
d = (y4-y3)*(x2-x1)-(x4-x3)*(y2-y1);
if (fabs(d) > tol) {
/*
* parallel or skew case
*/
u1 = n1 / d;
u2 = n2 / d;
if (u1 < -tol || u1 >1+tol || u2 < -tol || u2 > 1+tol) {
return 0;
}
if (fabs(u1) <= tol) {
inter.x = x1;
inter.y = y1;
} else if (fabs(u1-1.0) <= tol) {
inter.x = x2;
inter.y = y2;
} else if (fabs(u2) <= tol) {
inter.x = x3;
inter.y = y3;
} else if (fabs(u2-1.0) <= tol) {
inter.x = x4;
inter.y = y4;
} else {
inter.x = x1 + u1 * (x2 - x1);
inter.y = y1 + u1 * (y2 - y1);
}
return 1;
}
/*
* case when both lines are coincident
*/
if (!(fabs(n1) < tol && fabs(n2) < tol)) {
return 0;
}
/*
* Check to see if X1 lies in X3-X4
*/
if (isPointOnLineSegment(x1, y1, x3, y3, x4, y4)) {
inter.x = x1;
inter.y = y1;
numInt++;
}
/*
* Check to see if X2 lies in X3-X4
*/
if (isPointOnLineSegment(x2, y2, x3, y3, x4, y4)) {
if (numInt == 0) {
inter.x = x2;
inter.y = y2;
} else {
intIfLine.x = x2;
intIfLine.y = y2;
return 2;
}
numInt++;
}
/*
* Check to see if X3 lies in X1-X2
*/
if (isPointOnLineSegment(x3, y3, x1, y1, x2, y2)) {
if (numInt == 0) {
inter.x = x3;
inter.y = y3;
} else {
intIfLine.x = x3;
intIfLine.y = y3;
return 2;
}
numInt++;
}
/*
* Check to see if X4 lies in X1-X2
*/
if (isPointOnLineSegment(x4, y4, x1, y1, x2, y2))
{
if (numInt==0)
{
inter.x = x4;
inter.y = y4;
}
else
{
intIfLine.x = x4;
intIfLine.y = y4;
/*
* Order in increasing distance to (X1,Y1)
*/
if (sqrt((x4-x1) * (x4-x1) + (y4-y1) * (y4-y1)) <
sqrt((inter.x-x1) * (inter.x-x1) + (inter.y-y1) * (inter.y-y1)))
{
intIfLine.x = inter.x;
intIfLine.y = inter.y;
inter.x = x4;
inter.y = y4;
}
}
}
return 2;
}