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Merge branch 'csg2d' into master

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This commit is contained in:
Matthias Hochsteger 2020-08-31 11:56:51 +02:00
commit 20b82ae7af
3 changed files with 154 additions and 38 deletions
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118
libsrc/geom2d/csg2d.cpp
View File

@ -24,7 +24,7 @@ void ComputeWeight( Spline & s, Point<2> p )
double A = (p[1]-a[1])*(b[0]-p[0]) - (p[0]-a[0])*(b[1]-p[1]);
double B = (p[1]-c[1])*(b[0]-p[0]) - (p[0]-c[0])*(b[1]-p[1]);
double det = sqrt(-A*B);
double tt = (B-det)/(A+det);
double tt = fabs(A+det)<EPSILON ? 1 : (B-det)/(A+det);
auto v = b-p;
int dim = fabs(v[0]) > fabs(v[1]) ? 0 : 1;
double weight = fabs(tt*(p[dim]-a[dim])/v[dim] + 1.0/tt*(p[dim]-c[dim])/v[dim]);
@ -268,7 +268,7 @@ IntersectionType IntersectSplineSegment( const Spline & s, const Point<2> & r0,
return ClassifyNonOverlappingIntersection(alpha, beta);
}
IntersectionType IntersectSplineSegment1( const Spline & s, const Point<2> & r0, const Point<2> & r1, double& alpha, double& beta )
IntersectionType IntersectSplineSegment1( const Spline & s, const Point<2> & r0, const Point<2> & r1, double& alpha, double& beta, bool first=false)
{
Point<2> p0 = s.StartPI();
Point<2> p1 = s.TangentPoint();
@ -310,11 +310,14 @@ IntersectionType IntersectSplineSegment1( const Spline & s, const Point<2> & r0,
}
int choice = 0;
if(vtype[0]==NO_INTERSECTION && vtype[1]!=NO_INTERSECTION)
choice = 1;
if(!first)
{
if(vtype[0]==NO_INTERSECTION && vtype[1]!=NO_INTERSECTION)
choice = 1;
if(valpha[0] < alpha+EPSILON)
choice = 1;
if(valpha[0] < alpha+EPSILON)
choice = 1;
}
if(valpha[choice] < alpha+EPSILON)
return NO_INTERSECTION;
@ -332,26 +335,38 @@ bool IsOverlapping( Spline p, Spline s, double & alpha, double & beta, Intersect
double lam0 = -1e3*EPSILON;
double lam1 = -1e3*EPSILON;
double lam2 = -1e3*EPSILON;
double lam3 = -1e3*EPSILON;
alpha=-1e8;
beta=-1e8;
double alpha_mid=-1e8;
double beta_mid=-1e8;
// Check if s.p0 lies on p and vice versa, also check if tangents are in same direction (TODO: TEST)
// If so, assume overlapping splines
// TODO: Better checks! False positives could happen here!
IntersectSplineSegment1( p, s.StartPI(), p_mid, lam0, alpha );
IntersectSplineSegment1( s, p.StartPI(), s_mid, lam1, beta );
IntersectSplineSegment1( p, s.StartPI(), p_mid, lam0, alpha, true );
IntersectSplineSegment1( s, p.StartPI(), s_mid, lam1, beta, true );
// Also check if midpoints lie on other spline
IntersectSplineSegment1( p, s.GetPoint(0.5), p_mid, lam2, alpha_mid, true );
IntersectSplineSegment1( s, p.GetPoint(0.5), s_mid, lam3, beta_mid, true );
auto tang0 = s.GetTangent(0.);
auto tang1 = p.GetTangent(alpha);
double err = tang0*tang1;
err*=err;
err *= 1.0/(tang0.Length2()*tang1.Length2());
if(fabs(lam0) < 1e3*EPSILON && fabs(lam1) < 1e3*EPSILON /*&& err < EPSILON*/)
{
type = ClassifyOverlappingIntersection( alpha, beta );
return true;
}
return false;
double constexpr eps = 1e3*EPSILON;
if(fabs(lam0)>eps) return false;
if(fabs(lam1)>eps) return false;
if(fabs(lam2)>eps) return false;
if(fabs(lam3)>eps) return false;
if(fabs(1.0-err)>eps) return false;
type = ClassifyOverlappingIntersection( alpha, beta );
return true;
}
bool IsInsideTrig( const array<Point<2>,3> & t, Point<2> r )
@ -1322,6 +1337,42 @@ Solid2d ClipSolids ( Solid2d s1, Solid2d s2, bool intersect)
return res;
}
bool Loop :: IsInside( Point<2> r ) const
{
int w = 0;
for(auto e : Edges(ALL))
{
int w_simple = CalcSide(*e.v0, *e.v1, r);
if(!e.v0->spline)
w += w_simple;
else
{
auto s = *e.v0->spline;
auto s0 = s.StartPI();
auto s1 = s.TangentPoint();
auto s2 = s.EndPI();
if(!IsInsideTrig( {s0, s1, s2} , r ))
w += w_simple;
else
{
// 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();
ComputeWeight( s, r );
double new_weight = s.GetWeight();
if(new_weight >= old_weight)
w += w_simple;
else
w += CalcSide(s0, s1, r) + CalcSide(s1, s2, r);
}
}
}
return ( (w % 2) != 0 );
}
Solid2d :: Solid2d(const Array<std::variant<Point<2>, EdgeInfo>> & points, string name_, string bc)
: name(name_)
{
@ -1370,29 +1421,23 @@ Solid2d Solid2d :: operator-(const Solid2d & other_) const
other.Append(RectanglePoly(-1e8, 1e8, -1e8, 1e8, "JUST_FOR_CLIPPING"));
auto res = ClipSolids(*this, other);
for (auto i : Range(other.polys))
{
auto & first = *other.polys[i].first;
if(first[0] == -1e8)
other.polys.DeleteElement(i);
}
res.name = name;
return res;
}
Solid2d Solid2d :: operator+=(const Solid2d & other)
Solid2d & Solid2d :: operator+=(const Solid2d & other)
{
*this = *this + other;
return *this;
}
Solid2d Solid2d :: operator*=(const Solid2d & other)
Solid2d & Solid2d :: operator*=(const Solid2d & other)
{
*this = *this * other;
return *this;
}
Solid2d Solid2d :: operator-=(const Solid2d & other)
Solid2d & Solid2d :: operator-=(const Solid2d & other)
{
*this = *this - other;
return *this;
@ -1432,25 +1477,42 @@ bool Solid2d :: IsInside( Point<2> r ) const
{
int w = 0;
for(auto & poly : polys)
for(auto v : poly.Vertices(ALL))
w += CalcSide(*v, *v->next, r);
w += poly.IsInside(r);
return ( (w % 2) != 0 );
}
bool Solid2d :: IsLeftInside( const Vertex & p0 )
{
auto & p1 = *p0.next;
if(p0.spline)
{
auto s = *p0.spline;
auto v = s.GetTangent(0.5);
auto n = Vec<2>{-v[1], v[0]};
auto q = s.GetPoint(0.5) + 1e-6*n;
return IsInside(q);
}
auto v = p1-p0;
auto n = Vec<2>{v[1], -v[0]};
auto n = Vec<2>{-v[1], v[0]};
auto q = p0 + 0.5*v + 1e-6*n;
return IsInside(q);
}
bool Solid2d :: IsRightInside( const Vertex & p0 )
{
auto & p1 = *p0.next;
if(p0.spline)
{
auto s = *p0.spline;
auto v = s.GetTangent(0.5);
auto n = Vec<2>{v[1], -v[0]};
auto q = s.GetPoint(0.5) + 1e-6*n;
return IsInside(q);
}
auto v = p1-p0;
auto n = Vec<2>{-v[1], v[0]};
auto n = Vec<2>{v[1], -v[0]};
auto q = p0 + 0.5*v + 1e-6*n;
return IsInside(q);
}
@ -1584,7 +1646,7 @@ shared_ptr<netgen::SplineGeometry2d> CSG2d :: GenerateSplineGeometry()
if(li!=ri)
{
if(s.IsLeftInside(p0) == flip)
if(s.IsLeftInside(p0) != flip)
ls.left = dom;
else
ls.right = dom;

14
libsrc/geom2d/csg2d.hpp
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@ -447,13 +447,7 @@ struct Loop
v->prev->pnext = std::move(v->pnext);
}
bool IsInside( Point<2> r ) const
{
int w = 0;
for(auto e : Edges(ALL))
w += CalcSide(*e.v0, *e.v1, r);
return ( (w % 2) != 0 );
}
bool IsInside( Point<2> r ) const;
EdgeIterator Edges(IteratorType iterType) const
{
@ -575,9 +569,9 @@ struct Solid2d
Solid2d operator-(const Solid2d & other) const;
Solid2d& operator=(const Solid2d & other) = default;
Solid2d operator+=(const Solid2d & other);
Solid2d operator*=(const Solid2d & other);
Solid2d operator-=(const Solid2d & other);
Solid2d& operator+=(const Solid2d & other);
Solid2d& operator*=(const Solid2d & other);
Solid2d& operator-=(const Solid2d & other);
void Append( const Loop & poly )
{

60
tests/pytest/test_csg2d.py Normal file
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@ -0,0 +1,60 @@
from netgen.geom2d import *
import pytest
import math
from pytest import approx
def test_two_circles():
c1 = Circle(center=(0,0), radius=1)
c2 = c1.Rotate(deg=45)
s = c1*c2
geo = CSG2d()
geo.Add(s)
m = geo.GenerateMesh()
assert len(m.Elements2D()) > 0
ngs = pytest.importorskip("ngsolve")
mesh = ngs.Mesh(m)
mesh.Curve(5)
assert ngs.Integrate(1.0, mesh) == approx(math.pi)
ngs.Draw(mesh)
def test_two_edge():
s = Solid2d( [(-1,0), cp(0,1), (1,0), cp(0,2)] )
geo = CSG2d()
geo.Add(s)
m = geo.GenerateMesh()
assert len(m.Elements2D()) > 0
ngs = pytest.importorskip("ngsolve")
g = geo.GenerateSplineGeometry()
ngs.Draw(g)
mesh = ngs.Mesh(m)
mesh.Curve(5)
ngs.Draw(mesh)
def test_trig_and_circle():
g = CSG2d()
trig = Solid2d( [(0,0), (1,1), (-1,1) ] ).BC("diamond")
circle = Circle( center=(0,0.101), radius=0.1).BC("circle") # TODO: Failing with center=(0,0.1)
d = trig-circle
g.Add(d)
g.Add(circle)
m = g.GenerateMesh(maxh=0.1)
assert len(m.Elements2D()) > 0
ngs = pytest.importorskip("ngsolve")
geo = g.GenerateSplineGeometry()
ngs.Draw(geo)
mesh = ngs.Mesh(m)
mesh.Curve(3)
ngs.Draw(mesh)
if __name__ == "__main__":
test_two_circles()
test_two_edge()
test_trig_and_circle()