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[WIP] Fix oracle function in csg2d

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This commit is contained in:
Matthias Hochsteger 2021-01-12 18:08:39 +01:00
parent ccc686830a
commit 96b9be9f9c
1 changed files with 84 additions and 10 deletions
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94
libsrc/geom2d/csg2d.cpp
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@ -422,6 +422,64 @@ bool IsCloseToTrig( const array<Point<2>,3> & t, Point<2> r, double eps=1e-4 )
return IsInsideTrig( t, r );
}
bool IsLeft( const Spline & s, Point<2> p )
{
Point<2> a = s.StartPI();
Point<2> b = s.TangentPoint();
Point<2> c = s.EndPI();
// simple check by approximating spline with segment
bool is_left = Area(p, a, c) > 0.0;
// not close to spline -> simple check valid
if(!IsCloseToTrig( {a, b, c} , p ))
return is_left;
// p is control point -> simple check valid
auto bp = p-b;
if(bp.Length2() < EPSILON)
return is_left;
double sab = Area(p, a, b);
double sbc = Area(p, b, c);
if(fabs(sab)<EPSILON)
return is_left;
if(fabs(sbc)<EPSILON)
return is_left;
// r close to spline, need exact test
// idea: compute weight, such that r lies on spline
// weight increases -> same side of spline as control point, simple test gives correct result
// weight decreases -> opposite side of spline as control point, adding control point to test polygon gives correct result
double old_weight = s.GetWeight();
auto s_tmp = s;
ComputeWeight( s_tmp, p );
double new_weight = s_tmp.GetWeight();
if(new_weight>old_weight)
return is_left;
double sabc = Area(a, b, c);
if (sabc > 0)
{
// chain makes a left turn
if (sab > 0 && sbc > 0)
return true;
else
return false;
}
else
{
// chain makes a right turn (or is straight)
if (sab < 0 && sbc < 0)
return false;
else
return true;
}
}
IntersectionType IntersectTrig( Point<2> p0, Point<2> p1, const array<Point<2>,3> & trig)
{
@ -850,15 +908,26 @@ RelativePositionType oracle(bool prev, Vertex* P1, Vertex* P2, Vertex* P3)
Point<2> p2 = *P2;
Point<2> p3 = *P3;
double s1, s2, s3;
if(P1->spline)
p1 = P1->spline->TangentPoint();
{
s1 = IsLeft(*P1->spline, q) ? 1 : -1;
p1 = P1->spline->TangentPoint();
}
else
s1 = Area( q, p1, p2);
if(P2->spline)
p3 = P2->spline->TangentPoint();
{
s2 = IsLeft(*P2->spline, q) ? 1 : -1;
p2 = P2->spline->TangentPoint();
}
else
s2 = Area( q, p2, p3);
// check relative position of Q with respect to chain (P1,P2,P3)
double s1 = Area( q, p1, p2);
double s2 = Area( q, p2, p3);
double s3 = Area( p1, p2, p3);
s3 = Area( p1, p2, p3);
if (s3 > 0)
{
@ -878,6 +947,14 @@ RelativePositionType oracle(bool prev, Vertex* P1, Vertex* P2, Vertex* P3)
}
}
RelativePositionType oracle(bool prev, Vertex* P2)
{
Vertex* P1 = P2->prev;
Vertex* P3 = P2->next;
return oracle(prev, P1, P2, P3);
}
void LabelIntersections(Solid2d & sp, Solid2d & sq, Solid2d & sr, bool UNION)
{
auto & PP = sp.polys;
@ -890,12 +967,9 @@ void LabelIntersections(Solid2d & sp, Solid2d & sq, Solid2d & sr, bool UNION)
{
// determine local configuration at this intersection vertex
Vertex* P_m = I->prev;
Vertex* P_p = I->next;
// check positions of Q- and Q+ relative to (P-, I, P+)
RelativePositionType Q_m_type = oracle(true, P_m, I, P_p);
RelativePositionType Q_p_type = oracle(false, P_m, I, P_p);
RelativePositionType Q_m_type = oracle(true, I);
RelativePositionType Q_p_type = oracle(false, I);
// check non-overlapping cases
if ((Q_m_type == LEFT && Q_p_type == RIGHT) ||