Public Functions
	Edge (const Vertices &v, int _edge)

bool	intersect (const Edge &other, Q27Dot5 y, bool det_positive) const

bool	isLeftOf (const Edge &other, Q27Dot5 y) const

Q27Dot5	positionAt (Q27Dot5 y) const

Public Variables
int	edge

bool	free

bool	intersect_left

bool	intersect_right

bool	mark

const Vertex *	v0

const Vertex *	v1

signed int	winding: 8

Q27Dot5	y_left

Q27Dot5	y_right

Detailed Description

Definition at line 111 of file qtessellator.cpp.

Constructors and Destructors

◆ Edge()

QTessellatorPrivate::Edge::Edge	(	const Vertices &	v,
		int	_edge
	)

Definition at line 241 of file qtessellator.cpp.

 {
     this->edge = edge;
     intersect_left = intersect_right = true;
     mark = false;
     free = false;
 
     v0 = vertices[edge];
     v1 = vertices.next(v0);
 
     Q_ASSERT(v0->y != v1->y);
 
     if (v0->y > v1->y) {
         qSwap(v0, v1);
         winding = -1;
     } else {
         winding = 1;
     }
     y_left = y_right = v0->y;
 }

Functions

◆ intersect()

bool QTessellatorPrivate::Edge::intersect	(	const Edge &	other,
		Q27Dot5 *	y,
		bool *	det_positive
	)		const

Definition at line 284 of file qtessellator.cpp.

Referenced by QTessellatorPrivate::addIntersection().

 {
     qint64 a1 = v1->y - v0->y;
     qint64 b1 = v0->x - v1->x;
 
     qint64 a2 = other.v1->y - other.v0->y;
     qint64 b2 = other.v0->x - other.v1->x;
 
     qint64 det = a1 * b2 - a2 * b1;
     if (det == 0)
         return false;
 
     qint64 c1 = qint64(v1->x) * v0->y - qint64(v0->x) * v1->y;
 
     qint64 r3 = a1 * other.v0->x + b1 * other.v0->y + c1;
     qint64 r4 = a1 * other.v1->x + b1 * other.v1->y + c1;
 
     // Check signs of r3 and r4.  If both point 3 and point 4 lie on
     // same side of line 1, the line segments do not intersect.
     QDEBUG() << "        " << r3 << r4;
     if (r3 != 0 && r4 != 0 && sameSign( r3, r4 ))
         return false;
 
     qint64 c2 = qint64(other.v1->x) * other.v0->y - qint64(other.v0->x) * other.v1->y;
 
     qint64 r1 = a2 * v0->x + b2 * v0->y + c2;
     qint64 r2 = a2 * v1->x + b2 * v1->y + c2;
 
     // Check signs of r1 and r2.  If both point 1 and point 2 lie
     // on same side of second line segment, the line segments do not intersect.
     QDEBUG() << "        " << r1 << r2;
     if (r1 != 0 && r2 != 0 && sameSign( r1, r2 ))
         return false;
 
     // The det/2 is to get rounding instead of truncating.  It
     // is added or subtracted to the numerator, depending upon the
     // sign of the numerator.
     qint64 offset = det < 0 ? -det : det;
     offset >>= 1;
 
     qint64 num = a2 * c1 - a1 * c2;
     *y = ( num < 0 ? num - offset : num + offset ) / det;
 
     *det_positive = (det > 0);
 
     return true;
 }

◆ isLeftOf()

bool QTessellatorPrivate::Edge::isLeftOf	(	const Edge &	other,
		Q27Dot5	y
	)		const

Definition at line 334 of file qtessellator.cpp.

Referenced by QTessellatorPrivate::EdgeSorter::operator()().

 {
 //     QDEBUG() << "isLeftOf" << edge << other.edge << y;
     qint64 a1 = v1->y - v0->y;
     qint64 b1 = v0->x - v1->x;
     qint64 a2 = other.v1->y - other.v0->y;
     qint64 b2 = other.v0->x - other.v1->x;
 
     qint64 c2 = qint64(other.v1->x) * other.v0->y - qint64(other.v0->x) * other.v1->y;
 
     qint64 det = a1 * b2 - a2 * b1;
     if (det == 0) {
         // lines are parallel. Only need to check side of one point
         // fixed ordering for coincident edges
         qint64 r1 = a2 * v0->x + b2 * v0->y + c2;
 //         QDEBUG() << "det = 0" << r1;
         if (r1 == 0)
             return edge < other.edge;
         return (r1 < 0);
     }
 
     // not parallel, need to find the y coordinate of the intersection point
     qint64 c1 = qint64(v1->x) * v0->y - qint64(v0->x) * v1->y;
 
     qint64 offset = det < 0 ? -det : det;
     offset >>= 1;
 
     qint64 num = a2 * c1 - a1 * c2;
     qint64 yi = ( num < 0 ? num - offset : num + offset ) / det;
 //     QDEBUG() << "    num=" << num << "offset=" << offset << "det=" << det;
 
     return ((yi > y) ^ (det < 0));
 }

◆ positionAt()

Q27Dot5 QTessellatorPrivate::Edge::positionAt ( Q27Dot5 y ) const

Definition at line 379 of file qtessellator.cpp.

Referenced by QTessellatorPrivate::processIntersections().

 {
     if (y == v0->y)
         return v0->x;
     else if (y == v1->y)
         return v1->x;
 
     qint64 d = v1->x - v0->x;
     return (v0->x + d*(y - v0->y)/(v1->y-v0->y));
 }