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OrcaSlicer-bambulab/src/libnest2d/include/libnest2d/geometry_traits_nfp.hpp
2018-10-24 14:17:56 +02:00

283 lines
8.4 KiB
C++

#ifndef GEOMETRIES_NOFITPOLYGON_HPP
#define GEOMETRIES_NOFITPOLYGON_HPP
#include "geometry_traits.hpp"
#include <algorithm>
#include <functional>
#include <vector>
#include <iterator>
namespace libnest2d {
namespace __nfp {
// Do not specialize this...
template<class RawShape>
inline bool _vsort(const TPoint<RawShape>& v1, const TPoint<RawShape>& v2)
{
using Coord = TCoord<TPoint<RawShape>>;
Coord &&x1 = getX(v1), &&x2 = getX(v2), &&y1 = getY(v1), &&y2 = getY(v2);
auto diff = y1 - y2;
if(std::abs(diff) <= std::numeric_limits<Coord>::epsilon())
return x1 < x2;
return diff < 0;
}
template<class EdgeList, class RawShape, class Vertex = TPoint<RawShape>>
inline void buildPolygon(const EdgeList& edgelist,
RawShape& rpoly,
Vertex& top_nfp)
{
namespace sl = shapelike;
auto& rsh = sl::contour(rpoly);
sl::reserve(rsh, 2*edgelist.size());
// Add the two vertices from the first edge into the final polygon.
sl::addVertex(rsh, edgelist.front().first());
sl::addVertex(rsh, edgelist.front().second());
// Sorting function for the nfp reference vertex search
auto& cmp = _vsort<RawShape>;
// the reference (rightmost top) vertex so far
top_nfp = *std::max_element(sl::cbegin(rsh), sl::cend(rsh), cmp );
auto tmp = std::next(sl::begin(rsh));
// Construct final nfp by placing each edge to the end of the previous
for(auto eit = std::next(edgelist.begin());
eit != edgelist.end();
++eit)
{
auto d = *tmp - eit->first();
Vertex p = eit->second() + d;
sl::addVertex(rsh, p);
// Set the new reference vertex
if(cmp(top_nfp, p)) top_nfp = p;
tmp = std::next(tmp);
}
}
template<class Container, class Iterator = typename Container::iterator>
void advance(Iterator& it, Container& cont, bool direction)
{
int dir = direction ? 1 : -1;
if(dir < 0 && it == cont.begin()) it = std::prev(cont.end());
else it += dir;
if(dir > 0 && it == cont.end()) it = cont.begin();
}
}
/// A collection of static methods for handling the no fit polygon creation.
namespace nfp {
const double BP2D_CONSTEXPR TwoPi = 2*Pi;
/// The complexity level of a polygon that an NFP implementation can handle.
enum class NfpLevel: unsigned {
CONVEX_ONLY,
ONE_CONVEX,
BOTH_CONCAVE,
ONE_CONVEX_WITH_HOLES,
BOTH_CONCAVE_WITH_HOLES
};
template<class RawShape>
using NfpResult = std::pair<RawShape, TPoint<RawShape>>;
template<class RawShape> struct MaxNfpLevel {
static const BP2D_CONSTEXPR NfpLevel value = NfpLevel::CONVEX_ONLY;
};
// Shorthand for a pile of polygons
template<class RawShape>
using Shapes = TMultiShape<RawShape>;
/**
* Merge a bunch of polygons with the specified additional polygon.
*
* \tparam RawShape the Polygon data type.
* \param shc The pile of polygons that will be unified with sh.
* \param sh A single polygon to unify with shc.
*
* \return A set of polygons that is the union of the input polygons. Note that
* mostly it will be a set containing only one big polygon but if the input
* polygons are disjunct than the resulting set will contain more polygons.
*/
template<class RawShapes>
inline RawShapes merge(const RawShapes& /*shc*/)
{
static_assert(always_false<RawShapes>::value,
"Nfp::merge(shapes, shape) unimplemented!");
}
/**
* Merge a bunch of polygons with the specified additional polygon.
*
* \tparam RawShape the Polygon data type.
* \param shc The pile of polygons that will be unified with sh.
* \param sh A single polygon to unify with shc.
*
* \return A set of polygons that is the union of the input polygons. Note that
* mostly it will be a set containing only one big polygon but if the input
* polygons are disjunct than the resulting set will contain more polygons.
*/
template<class RawShape>
inline TMultiShape<RawShape> merge(const TMultiShape<RawShape>& shc,
const RawShape& sh)
{
auto m = nfp::merge(shc);
m.emplace_back(sh);
return nfp::merge(m);
}
/**
* Get the vertex of the polygon that is at the lowest values (bottom) in the Y
* axis and if there are more than one vertices on the same Y coordinate than
* the result will be the leftmost (with the highest X coordinate).
*/
template<class RawShape>
inline TPoint<RawShape> leftmostDownVertex(const RawShape& sh)
{
// find min x and min y vertex
auto it = std::min_element(shapelike::cbegin(sh), shapelike::cend(sh),
__nfp::_vsort<RawShape>);
return it == shapelike::cend(sh) ? TPoint<RawShape>() : *it;;
}
/**
* Get the vertex of the polygon that is at the highest values (top) in the Y
* axis and if there are more than one vertices on the same Y coordinate than
* the result will be the rightmost (with the lowest X coordinate).
*/
template<class RawShape>
TPoint<RawShape> rightmostUpVertex(const RawShape& sh)
{
// find max x and max y vertex
auto it = std::max_element(shapelike::cbegin(sh), shapelike::cend(sh),
__nfp::_vsort<RawShape>);
return it == shapelike::cend(sh) ? TPoint<RawShape>() : *it;
}
/**
* A method to get a vertex from a polygon that always maintains a relative
* position to the coordinate system: It is always the rightmost top vertex.
*
* This way it does not matter in what order the vertices are stored, the
* reference will be always the same for the same polygon.
*/
template<class RawShape>
inline TPoint<RawShape> referenceVertex(const RawShape& sh)
{
return rightmostUpVertex(sh);
}
/**
* The "trivial" Cuninghame-Green implementation of NFP for convex polygons.
*
* You can use this even if you provide implementations for the more complex
* cases (Through specializing the the NfpImpl struct). Currently, no other
* cases are covered in the library.
*
* Complexity should be no more than nlogn (std::sort) in the number of edges
* of the input polygons.
*
* \tparam RawShape the Polygon data type.
* \param sh The stationary polygon
* \param cother The orbiting polygon
* \return Returns a pair of the NFP and its reference vertex of the two input
* polygons which have to be strictly convex. The resulting NFP is proven to be
* convex as well in this case.
*
*/
template<class RawShape>
inline NfpResult<RawShape> nfpConvexOnly(const RawShape& sh,
const RawShape& other)
{
using Vertex = TPoint<RawShape>; using Edge = _Segment<Vertex>;
namespace sl = shapelike;
RawShape rsh; // Final nfp placeholder
Vertex top_nfp;
std::vector<Edge> edgelist;
auto cap = sl::contourVertexCount(sh) + sl::contourVertexCount(other);
// Reserve the needed memory
edgelist.reserve(cap);
sl::reserve(rsh, static_cast<unsigned long>(cap));
{ // place all edges from sh into edgelist
auto first = sl::cbegin(sh);
auto next = std::next(first);
while(next != sl::cend(sh)) {
edgelist.emplace_back(*(first), *(next));
++first; ++next;
}
}
{ // place all edges from other into edgelist
auto first = sl::cbegin(other);
auto next = std::next(first);
while(next != sl::cend(other)) {
edgelist.emplace_back(*(next), *(first));
++first; ++next;
}
}
// Sort the edges by angle to X axis.
std::sort(edgelist.begin(), edgelist.end(),
[](const Edge& e1, const Edge& e2)
{
return e1.angleToXaxis() > e2.angleToXaxis();
});
__nfp::buildPolygon(edgelist, rsh, top_nfp);
return {rsh, top_nfp};
}
// Specializable NFP implementation class. Specialize it if you have a faster
// or better NFP implementation
template<class RawShape, NfpLevel nfptype>
struct NfpImpl {
NfpResult<RawShape> operator()(const RawShape& sh, const RawShape& other)
{
static_assert(nfptype == NfpLevel::CONVEX_ONLY,
"Nfp::noFitPolygon() unimplemented!");
// Libnest2D has a default implementation for convex polygons and will
// use it if feasible.
return nfpConvexOnly(sh, other);
}
};
/// Helper function to get the NFP
template<NfpLevel nfptype, class RawShape>
inline NfpResult<RawShape> noFitPolygon(const RawShape& sh,
const RawShape& other)
{
NfpImpl<RawShape, nfptype> nfps;
return nfps(sh, other);
}
}
}
#endif // GEOMETRIES_NOFITPOLYGON_HPP