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Merge branch 'tm_arrange_rot'

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fixes #6606
This commit is contained in:
tamasmeszaros 2021-06-22 11:52:10 +02:00
commit 15c0183647
2 changed files with 191 additions and 72 deletions
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242
src/libnest2d/include/libnest2d/utils/rotcalipers.hpp
View File

@ -90,12 +90,29 @@ inline R rectarea(const Pt& w, const std::array<It, 4>& rect)
return rectarea<Pt, Unit, R>(w, *rect[0], *rect[1], *rect[2], *rect[3]);
}
template<class Pt, class Unit = TCompute<Pt>, class R = TCompute<Pt>>
inline R rectarea(const Pt& w, // the axis
const Unit& a,
const Unit& b)
{
R m = R(a) / pl::magnsq<Pt, Unit>(w);
m = m * b;
return m;
};
template<class R, class Pt, class Unit>
inline R rectarea(const RotatedBox<Pt, Unit> &rb)
{
return rectarea<Pt, Unit, R>(rb.axis(), rb.bottom_extent(), rb.right_extent());
};
// This function is only applicable to counter-clockwise oriented convex
// polygons where only two points can be collinear witch each other.
template <class RawShape,
class Unit = TCompute<RawShape>,
class Ratio = TCompute<RawShape>>
RotatedBox<TPoint<RawShape>, Unit> minAreaBoundingBox(const RawShape& sh)
template <class RawShape,
class Unit = TCompute<RawShape>,
class Ratio = TCompute<RawShape>,
class VisitFn>
void rotcalipers(const RawShape& sh, VisitFn &&visitfn)
{
using Point = TPoint<RawShape>;
using Iterator = typename TContour<RawShape>::const_iterator;
@ -104,21 +121,21 @@ RotatedBox<TPoint<RawShape>, Unit> minAreaBoundingBox(const RawShape& sh)
// Get the first and the last vertex iterator
auto first = sl::cbegin(sh);
auto last = std::prev(sl::cend(sh));
// Check conditions and return undefined box if input is not sane.
if(last == first) return {};
if(last == first) return;
if(getX(*first) == getX(*last) && getY(*first) == getY(*last)) --last;
if(last - first < 2) return {};
if(last - first < 2) return;
RawShape shcpy; // empty at this point
{
{
Point p = *first, q = *std::next(first), r = *last;
// Determine orientation from first 3 vertex (should be consistent)
Unit d = (Unit(getY(q)) - getY(p)) * (Unit(getX(r)) - getX(p)) -
(Unit(getX(q)) - getX(p)) * (Unit(getY(r)) - getY(p));
if(d > 0) {
if(d > 0) {
// The polygon is clockwise. A flip is needed (for now)
sl::reserve(shcpy, last - first);
auto it = last; while(it != first) sl::addVertex(shcpy, *it--);
@ -126,69 +143,69 @@ RotatedBox<TPoint<RawShape>, Unit> minAreaBoundingBox(const RawShape& sh)
first = sl::cbegin(shcpy); last = std::prev(sl::cend(shcpy));
}
}
// Cyclic iterator increment
auto inc = [&first, &last](Iterator& it) {
if(it == last) it = first; else ++it;
if(it == last) it = first; else ++it;
};
// Cyclic previous iterator
auto prev = [&first, &last](Iterator it) {
return it == first ? last : std::prev(it);
auto prev = [&first, &last](Iterator it) {
return it == first ? last : std::prev(it);
};
// Cyclic next iterator
auto next = [&first, &last](Iterator it) {
return it == last ? first : std::next(it);
return it == last ? first : std::next(it);
};
// Establish initial (axis aligned) rectangle support verices by determining
// Establish initial (axis aligned) rectangle support verices by determining
// polygon extremes:
auto it = first;
Iterator minX = it, maxX = it, minY = it, maxY = it;
do { // Linear walk through the vertices and save the extreme positions
Point v = *it, d = v - *minX;
if(getX(d) < 0 || (getX(d) == 0 && getY(d) < 0)) minX = it;
d = v - *maxX;
if(getX(d) > 0 || (getX(d) == 0 && getY(d) > 0)) maxX = it;
d = v - *minY;
if(getY(d) < 0 || (getY(d) == 0 && getX(d) > 0)) minY = it;
d = v - *maxY;
if(getY(d) > 0 || (getY(d) == 0 && getX(d) < 0)) maxY = it;
} while(++it != std::next(last));
// Update the vertices defining the bounding rectangle. The rectangle with
// the smallest rotation is selected and the supporting vertices are
// the smallest rotation is selected and the supporting vertices are
// returned in the 'rect' argument.
auto update = [&next, &inc]
(const Point& w, std::array<Iterator, 4>& rect)
(const Point& w, std::array<Iterator, 4>& rect)
{
Iterator B = rect[0], Bn = next(B);
Iterator R = rect[1], Rn = next(R);
Iterator T = rect[2], Tn = next(T);
Iterator L = rect[3], Ln = next(L);
Point b = *Bn - *B, r = *Rn - *R, t = *Tn - *T, l = *Ln - *L;
Point pw = perp(w);
using Pt = Point;
Unit dotwpb = dot<Pt, Unit>( w, b), dotwpr = dot<Pt, Unit>(-pw, r);
Unit dotwpt = dot<Pt, Unit>(-w, t), dotwpl = dot<Pt, Unit>( pw, l);
Unit dw = magnsq<Pt, Unit>(w);
std::array<Ratio, 4> angles;
angles[0] = (Ratio(dotwpb) / magnsq<Pt, Unit>(b)) * dotwpb;
angles[1] = (Ratio(dotwpr) / magnsq<Pt, Unit>(r)) * dotwpr;
angles[2] = (Ratio(dotwpt) / magnsq<Pt, Unit>(t)) * dotwpt;
angles[3] = (Ratio(dotwpl) / magnsq<Pt, Unit>(l)) * dotwpl;
using AngleIndex = std::pair<Ratio, size_t>;
std::vector<AngleIndex> A; A.reserve(4);
@ -196,65 +213,84 @@ RotatedBox<TPoint<RawShape>, Unit> minAreaBoundingBox(const RawShape& sh)
if(rect[i] != rect[j] && angles[i] < dw) {
auto iv = std::make_pair(angles[i], i);
auto it = std::lower_bound(A.begin(), A.end(), iv,
[](const AngleIndex& ai,
const AngleIndex& aj)
{
return ai.first > aj.first;
[](const AngleIndex& ai,
const AngleIndex& aj)
{
return ai.first > aj.first;
});
A.insert(it, iv);
}
}
// The polygon is supposed to be a rectangle.
if(A.empty()) return false;
auto amin = A.front().first;
auto imin = A.front().second;
for(auto& a : A) if(a.first == amin) inc(rect[a.second]);
std::rotate(rect.begin(), rect.begin() + imin, rect.end());
return true;
};
Point w(1, 0);
Point w_min = w;
Ratio minarea((Unit(getX(*maxX)) - getX(*minX)) *
(Unit(getY(*maxY)) - getY(*minY)));
std::array<Iterator, 4> rect = {minY, maxX, maxY, minX};
std::array<Iterator, 4> minrect = rect;
{
Unit a = dot<Point, Unit>(w, *rect[1] - *rect[3]);
Unit b = dot<Point, Unit>(-perp(w), *rect[2] - *rect[0]);
if (!visitfn(RotatedBox<Point, Unit>{w, a, b}))
return;
}
// An edge might be examined twice in which case the algorithm terminates.
size_t c = 0, count = last - first + 1;
std::vector<bool> edgemask(count, false);
while(c++ < count)
{
while(c++ < count)
{
// Update the support vertices, if cannot be updated, break the cycle.
if(! update(w, rect)) break;
size_t eidx = size_t(rect[0] - first);
if(edgemask[eidx]) break;
edgemask[eidx] = true;
// get the unnormalized direction vector
w = *rect[0] - *prev(rect[0]);
// get the area of the rotated rectangle
Ratio rarea = rectarea<Point, Unit, Ratio>(w, rect);
// Update min area and the direction of the min bounding box;
if(rarea <= minarea) { w_min = w; minarea = rarea; minrect = rect; }
Unit a = dot<Point, Unit>(w, *rect[1] - *rect[3]);
Unit b = dot<Point, Unit>(-perp(w), *rect[2] - *rect[0]);
if (!visitfn(RotatedBox<Point, Unit>{w, a, b}))
break;
}
Unit a = dot<Point, Unit>(w_min, *minrect[1] - *minrect[3]);
Unit b = dot<Point, Unit>(-perp(w_min), *minrect[2] - *minrect[0]);
RotatedBox<Point, Unit> bb(w_min, a, b);
return bb;
}
// This function is only applicable to counter-clockwise oriented convex
// polygons where only two points can be collinear witch each other.
template <class S,
class Unit = TCompute<S>,
class Ratio = TCompute<S>>
RotatedBox<TPoint<S>, Unit> minAreaBoundingBox(const S& sh)
{
RotatedBox<TPoint<S>, Unit> minbox;
Ratio minarea = std::numeric_limits<Unit>::max();
auto minfn = [&minarea, &minbox](const RotatedBox<TPoint<S>, Unit> &rbox){
Ratio area = rectarea<Ratio>(rbox);
if (area <= minarea) {
minarea = area;
minbox = rbox;
}
return true; // continue search
};
rotcalipers<S, Unit, Ratio>(sh, minfn);
return minbox;
}
template <class RawShape> Radians minAreaBoundingBoxRotation(const RawShape& sh)
@ -262,7 +298,75 @@ template <class RawShape> Radians minAreaBoundingBoxRotation(const RawShape& sh)
return minAreaBoundingBox(sh).angleToX();
}
// Function to find a rotation for a shape that makes it fit into a box.
//
// The method is based on finding a pair of rotations from the rotating calipers
// algorithm such that the aspect ratio is changing from being smaller than
// that of the target to being bigger or vice versa. So that the correct
// AR is somewhere between the obtained pair of angles. Then bisecting that
// interval is sufficient to find the correct angle.
//
// The argument eps is the absolute error limit for the searched angle interval.
template<class S, class Unit = TCompute<S>, class Ratio = TCompute<S>>
Radians fitIntoBoxRotation(const S &shape, const _Box<TPoint<S>> &box, Radians eps = 1e-4)
{
constexpr auto get_aspect_r = [](const auto &b) -> double {
return double(b.width()) / b.height();
};
auto aspect_r = get_aspect_r(box);
RotatedBox<TPoint<S>, Unit> prev_rbox;
Radians a_from = 0., a_to = 0.;
auto visitfn = [&](const RotatedBox<TPoint<S>, Unit> &rbox) {
bool lower_prev = get_aspect_r(prev_rbox) < aspect_r;
bool lower_current = get_aspect_r(rbox) < aspect_r;
if (lower_prev != lower_current) {
a_from = prev_rbox.angleToX();
a_to = rbox.angleToX();
return false;
}
return true;
};
rotcalipers<S, Unit, Ratio>(shape, visitfn);
auto rot_shape_bb = [&shape](Radians r) {
auto s = shape;
sl::rotate(s, r);
return sl::boundingBox(s);
};
auto rot_aspect_r = [&rot_shape_bb, &get_aspect_r](Radians r) {
return get_aspect_r(rot_shape_bb(r));
};
// Lets bisect the retrieved interval where the correct aspect ratio is.
double ar_from = rot_aspect_r(a_from);
auto would_fit = [&box](const _Box<TPoint<S>> &b) {
return b.width() < box.width() && b.height() < box.height();
};
Radians middle = (a_from + a_to) / 2.;
_Box<TPoint<S>> box_middle = rot_shape_bb(middle);
while (!would_fit(box_middle) && std::abs(a_to - a_from) > eps)
{
double ar_middle = get_aspect_r(box_middle);
if ((ar_from < aspect_r) != (ar_middle < aspect_r))
a_to = middle;
else
a_from = middle;
ar_from = rot_aspect_r(a_from);
middle = (a_from + a_to) / 2.;
box_middle = rot_shape_bb(middle);
}
return middle;
}
} // namespace libnest2d
#endif // ROTCALIPERS_HPP

21
src/libslic3r/Arrange.cpp
View File

@ -379,7 +379,7 @@ public:
});
if (stopcond) m_pck.stopCondition(stopcond);
m_pck.configure(m_pconf);
}
@ -472,6 +472,12 @@ template<class S> Radians min_area_boundingbox_rotation(const S &sh)
.angleToX();
}
template<class S>
Radians fit_into_box_rotation(const S &sh, const _Box<TPoint<S>> &box)
{
return fitIntoBoxRotation<S, TCompute<S>, boost::rational<LargeInt>>(sh, box);
}
template<class BinT> // Arrange for arbitrary bin type
void _arrange(
std::vector<Item> & shapes,
@ -509,10 +515,19 @@ void _arrange(
// Use the minimum bounding box rotation as a starting point.
// TODO: This only works for convex hull. If we ever switch to concave
// polygon nesting, a convex hull needs to be calculated.
if (params.allow_rotations)
for (auto &itm : shapes)
if (params.allow_rotations) {
for (auto &itm : shapes) {
itm.rotation(min_area_boundingbox_rotation(itm.rawShape()));
// If the item is too big, try to find a rotation that makes it fit
if constexpr (std::is_same_v<BinT, Box>) {
auto bb = itm.boundingBox();
if (bb.width() >= bin.width() || bb.height() >= bin.height())
itm.rotate(fit_into_box_rotation(itm.transformedShape(), bin));
}
}
}
arranger(inp.begin(), inp.end());
for (Item &itm : inp) itm.inflate(-infl);
}