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clean up in the cross product alternatives

This commit is contained in:
Andreas Fabri 2025-05-22 15:20:14 +01:00
parent c63c2a24e2
commit 0f86fa6d23
2 changed files with 13 additions and 10 deletions
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1
Surface_mesh_simplification/include/CGAL/Cartesian/CrossProduct.h
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@ -52,6 +52,7 @@ namespace CGAL {
return a*b - c*d; return a*b - c*d;
} }
} // namespace CGAL } // namespace CGAL
#endif // CGAL_CARTESIAN_CROSSPRODUCT_H // #endif // CGAL_CARTESIAN_CROSSPRODUCT_H //

22
Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/internal/Lindstrom_Turk_core.h
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@ -152,7 +152,8 @@ private :
} }
#endif #endif
static Vector SL_cross_product(const Vector& a, const Vector& b) // balanced solution based on abusing the fact that here we expect u and v to have similar coordinates
static Vector robust_cross_product(const Vector& a, const Vector& b)
{ {
const FT ax=a.x(), ay=a.y(), az=a.z(); const FT ax=a.x(), ay=a.y(), az=a.z();
const FT bx=b.x(), by=b.y(), bz=b.z(); const FT bx=b.x(), by=b.y(), bz=b.z();
@ -184,9 +185,10 @@ private :
exv.exact(); exv.exact();
return to_approx(exv); return to_approx(exv);
} }
#endif
static Vector X_product(const Vector& u, const Vector& v)
static Vector experimental_cross_product(const Vector& u, const Vector& v)
{ {
#if 0 #if 0
// this can create large errors and spiky meshes for kernels with inexact constructions // this can create large errors and spiky meshes for kernels with inexact constructions
@ -201,18 +203,18 @@ private :
return { diff_of_products(u.y(), v.z(), u.z(), v.y()), return { diff_of_products(u.y(), v.z(), u.z(), v.y()),
diff_of_products(u.z(), v.x(), u.x(), v.z()), diff_of_products(u.z(), v.x(), u.x(), v.z()),
diff_of_products(u.x(), v.y(), u.y(), v.x()) }; diff_of_products(u.x(), v.y(), u.y(), v.x()) };
#elif 1
// balanced solution based on abusing the fact that here we expect u and v to have similar coordinates
return SL_cross_product(u, v);
#elif 0 #elif 0
// obviously too slow // obviously too slow
return exact_cross_product(u, v); return exact_cross_product(u, v);
#endif #endif
} }
#endif
static Vector point_cross_product(const Point& a, const Point& b) static Vector point_cross_product(const Point& a, const Point& b)
{ {
return X_product(a-ORIGIN, b-ORIGIN); return robust_cross_product(a-ORIGIN, b-ORIGIN);
} }
// This is the (uX)(Xu) product described in the Lindstrom-Turk paper // This is the (uX)(Xu) product described in the Lindstrom-Turk paper
@ -334,7 +336,7 @@ extract_triangle_data()
Vector v01 = p1 - p0; Vector v01 = p1 - p0;
Vector v02 = p2 - p0; Vector v02 = p2 - p0;
Vector lNormalV = X_product(v01,v02); Vector lNormalV = robust_cross_product(v01,v02);
FT lNormalL = point_cross_product(p0,p1) * (p2 - ORIGIN); FT lNormalL = point_cross_product(p0,p1) * (p2 - ORIGIN);
CGAL_SMS_LT_TRACE(1, " Extracting triangle v" << tri.v0 << "->v" << tri.v1 << "->v" << tri.v2 CGAL_SMS_LT_TRACE(1, " Extracting triangle v" << tri.v0 << "->v" << tri.v1 << "->v" << tri.v2
@ -660,10 +662,10 @@ add_constraint_if_alpha_compatible(const Vector& Ai,
FT l = CGAL_NTS sqrt(slai); FT l = CGAL_NTS sqrt(slai);
CGAL_SMS_LT_TRACE(3, " l: " << n_to_string(l)); CGAL_SMS_LT_TRACE(3, " l: " << n_to_string(l));
// Due to double number type, l may have a small value instead of zero (example sum of the face normals of a tetrahedron for volumic constraint) // Due to double number type, l may have a small value instead of zero (example sum of the face normals of a tetrahedron for volume constraint)
// if bi is greater than maxBb, we consider that l is zero // if bi is greater than maxBb, we consider that l is zero
CGAL_SMS_LT_TRACE(3, " error consider: " << (CGAL::abs(bi) / maxBb)); CGAL_SMS_LT_TRACE(3, " error consider: " << (CGAL::abs(bi) / maxBb));
if(l > (std::abs(bi) / maxBb)) if(l > (CGAL::abs(bi) / maxBb))
{ {
Vector Ain = Ai / l; Vector Ain = Ai / l;
FT bin = bi / l; FT bin = bi / l;