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PrusaSlicer/src/libslic3r/BuildVolume.cpp
Vojtech Bubnik cc44089440 New BuildVolume class was created, which detects build volume type (rectangular, 
circular, convex, concave) and performs efficient collision detection agains these build
volumes. As of now, collision detection is performed against a convex
hull of a concave build volume for efficency.

GCodeProcessor::Result renamed out of GCodeProcessor to GCodeProcessorResult,
so it could be forward declared.

Plater newly exports BuildVolume, not Bed3D. Bed3D is a rendering class,
while BuildVolume is a purely geometric class.

Reduced usage of global wxGetApp, the Bed3D is passed as a parameter
to View3D/Preview/GLCanvas.

Convex hull code was extracted from Geometry.cpp/hpp to Geometry/ConvexHulll.cpp,hpp.
New test inside_convex_polygon().
New efficent point inside polygon test: Decompose convex hull
to bottom / top parts and use the decomposition to detect point inside
a convex polygon in O(log n). decompose_convex_polygon_top_bottom(),
inside_convex_polygon().

New Circle constructing functions: circle_ransac() and circle_taubin_newton().

New polygon_is_convex() test with unit tests.
2021-11-16 10:15:51 +01:00

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#include "BuildVolume.hpp"
#include "ClipperUtils.hpp"
#include "Geometry/ConvexHull.hpp"
#include "GCode/GCodeProcessor.hpp"
#include "Point.hpp"
namespace Slic3r {
BuildVolume::BuildVolume(const std::vector<Vec2d> &bed_shape, const double max_print_height) : m_bed_shape(bed_shape), m_max_print_height(max_print_height)
{
assert(max_print_height >= 0);
m_polygon = Polygon::new_scale(bed_shape);
// Calcuate various metrics of the input polygon.
m_convex_hull = Geometry::convex_hull(m_polygon.points);
m_bbox = get_extents(m_convex_hull);
m_area = m_polygon.area();
BoundingBoxf bboxf = get_extents(bed_shape);
m_bboxf = BoundingBoxf3{ to_3d(bboxf.min, 0.), to_3d(bboxf.max, max_print_height) };
if (bed_shape.size() >= 4 && std::abs((m_area - double(m_bbox.size().x()) * double(m_bbox.size().y()))) < sqr(SCALED_EPSILON)) {
// Square print bed, use the bounding box for collision detection.
m_type = Type::Rectangle;
m_circle.center = 0.5 * (m_bbox.min.cast<double>() + m_bbox.max.cast<double>());
m_circle.radius = 0.5 * m_bbox.size().cast<double>().norm();
} else if (bed_shape.size() > 3) {
// Circle was discretized, formatted into text with limited accuracy, thus the circle was deformed.
// RANSAC is slightly more accurate than the iterative Taubin / Newton method with such an input.
// m_circle = Geometry::circle_taubin_newton(bed_shape);
m_circle = Geometry::circle_ransac(bed_shape);
bool is_circle = true;
#ifndef NDEBUG
// Measuring maximum absolute error of interpolating an input polygon with circle.
double max_error = 0;
#endif // NDEBUG
Vec2d prev = bed_shape.back();
for (const Vec2d &p : bed_shape) {
#ifndef NDEBUG
max_error = std::max(max_error, std::abs((p - m_circle.center).norm() - m_circle.radius));
#endif // NDEBUG
if (// Polygon vertices must lie very close the circle.
std::abs((p - m_circle.center).norm() - m_circle.radius) > 0.005 ||
// Midpoints of polygon edges must not undercat more than 3mm. This corresponds to 72 edges per circle generated by BedShapePanel::update_shape().
m_circle.radius - (0.5 * (prev + p) - m_circle.center).norm() > 3.) {
is_circle = false;
break;
}
prev = p;
}
if (is_circle) {
m_type = Type::Circle;
m_circle.center = scaled<double>(m_circle.center);
m_circle.radius = scaled<double>(m_circle.radius);
}
}
if (bed_shape.size() >= 3 && m_type == Type::Invalid) {
// Circle check is not used for Convex / Custom shapes, fill it with something reasonable.
m_circle = Geometry::smallest_enclosing_circle_welzl(m_convex_hull.points);
m_type = (m_convex_hull.area() - m_area) < sqr(SCALED_EPSILON) ? Type::Convex : Type::Custom;
// Initialize the top / bottom decomposition for inside convex polygon check. Do it with two different epsilons applied.
auto convex_decomposition = [](const Polygon &in, double epsilon) {
Polygon src = expand(in, float(epsilon)).front();
std::vector<Vec2d> pts;
pts.reserve(src.size());
for (const Point &pt : src.points)
pts.emplace_back(unscaled<double>(pt.cast<double>().eval()));
return Geometry::decompose_convex_polygon_top_bottom(pts);
};
m_top_bottom_convex_hull_decomposition_scene = convex_decomposition(m_convex_hull, SceneEpsilon);
m_top_bottom_convex_hull_decomposition_bed = convex_decomposition(m_convex_hull, BedEpsilon);
}
BOOST_LOG_TRIVIAL(debug) << "BuildVolume bed_shape clasified as: " << this->type_name();
}
#if 0
// Tests intersections of projected triangles, not just their vertices against a bounding box.
// This test also correctly evaluates collision of a non-convex object with the bounding box.
// Not used, slower than simple bounding box collision check and nobody complained about the inaccuracy of the simple test.
static inline BuildVolume::ObjectState rectangle_test(const indexed_triangle_set &its, const Transform3f &trafo, const Vec2f min, const Vec2f max, const float max_z)
{
bool inside = false;
bool outside = false;
auto sign = [](const Vec3f& pt) -> char { return pt.z() > 0 ? 1 : pt.z() < 0 ? -1 : 0; };
// Returns true if both inside and outside are set, thus early exit.
auto test_intersection = [&inside, &outside, min, max, max_z](const Vec3f& p1, const Vec3f& p2, const Vec3f& p3) -> bool {
// First test whether the triangle is completely inside or outside the bounding box.
Vec3f pmin = p1.cwiseMin(p2).cwiseMin(p3);
Vec3f pmax = p1.cwiseMax(p2).cwiseMax(p3);
bool tri_inside = false;
bool tri_outside = false;
if (pmax.x() < min.x() || pmin.x() > max.x() || pmax.y() < min.y() || pmin.y() > max.y()) {
// Separated by one of the rectangle sides.
tri_outside = true;
} else if (pmin.x() >= min.x() && pmax.x() <= max.x() && pmin.y() >= min.y() && pmax.y() <= max.y()) {
// Fully inside the rectangle.
tri_inside = true;
} else {
// Bounding boxes overlap. Test triangle sides against the bbox corners.
Vec2f v1(- p2.y() + p1.y(), p2.x() - p1.x());
Vec2f v2(- p2.y() + p2.y(), p3.x() - p2.x());
Vec2f v3(- p1.y() + p3.y(), p1.x() - p3.x());
bool ccw = cross2(v1, v2) > 0;
for (const Vec2f &p : { Vec2f{ min.x(), min.y() }, Vec2f{ min.x(), max.y() }, Vec2f{ max.x(), min.y() }, Vec2f{ max.x(), max.y() } }) {
auto dot = v1.dot(p);
if (ccw ? dot >= 0 : dot <= 0)
tri_inside = true;
else
tri_outside = true;
}
}
inside |= tri_inside;
outside |= tri_outside;
return inside && outside;
};
// Edge crosses the z plane. Calculate intersection point with the plane.
auto clip_edge = [](const Vec3f &p1, const Vec3f &p2) -> Vec3f {
const float t = (world_min_z - p1.z()) / (p2.z() - p1.z());
return { p1.x() + (p2.x() - p1.x()) * t, p1.y() + (p2.y() - p1.y()) * t, world_min_z };
};
// Clip at (p1, p2), p3 must be on the clipping plane.
// Returns true if both inside and outside are set, thus early exit.
auto clip_and_test1 = [&test_intersection, &clip_edge](const Vec3f &p1, const Vec3f &p2, const Vec3f &p3, bool p1above) -> bool {
Vec3f pa = clip_edge(p1, p2);
return p1above ? test_intersection(p1, pa, p3) : test_intersection(pa, p2, p3);
};
// Clip at (p1, p2) and (p2, p3).
// Returns true if both inside and outside are set, thus early exit.
auto clip_and_test2 = [&test_intersection, &clip_edge](const Vec3f &p1, const Vec3f &p2, const Vec3f &p3, bool p2above) -> bool {
Vec3f pa = clip_edge(p1, p2);
Vec3f pb = clip_edge(p2, p3);
return p2above ? test_intersection(pa, p2, pb) : test_intersection(p1, pa, p3) || test_intersection(p3, pa, pb);
};
for (const stl_triangle_vertex_indices &tri : its.indices) {
const Vec3f pts[3] = { trafo * its.vertices[tri(0)], trafo * its.vertices[tri(1)], trafo * its.vertices[tri(2)] };
char signs[3] = { sign(pts[0]), sign(pts[1]), sign(pts[2]) };
bool clips[3] = { signs[0] * signs[1] == -1, signs[1] * signs[2] == -1, signs[2] * signs[0] == -1 };
if (clips[0]) {
if (clips[1]) {
// Clipping at (pt0, pt1) and (pt1, pt2).
if (clip_and_test2(pts[0], pts[1], pts[2], signs[1] > 0))
break;
} else if (clips[2]) {
// Clipping at (pt0, pt1) and (pt0, pt2).
if (clip_and_test2(pts[2], pts[0], pts[1], signs[0] > 0))
break;
} else {
// Clipping at (pt0, pt1), pt2 must be on the clipping plane.
if (clip_and_test1(pts[0], pts[1], pts[2], signs[0] > 0))
break;
}
} else if (clips[1]) {
if (clips[2]) {
// Clipping at (pt1, pt2) and (pt0, pt2).
if (clip_and_test2(pts[0], pts[1], pts[2], signs[1] > 0))
break;
} else {
// Clipping at (pt1, pt2), pt0 must be on the clipping plane.
if (clip_and_test1(pts[1], pts[2], pts[0], signs[1] > 0))
break;
}
} else if (clips[2]) {
// Clipping at (pt0, pt2), pt1 must be on the clipping plane.
if (clip_and_test1(pts[2], pts[0], pts[1], signs[2] > 0))
break;
} else if (signs[0] >= 0 && signs[1] >= 0 && signs[2] >= 0) {
// The triangle is above or on the clipping plane.
if (test_intersection(pts[0], pts[1], pts[2]))
break;
}
}
return inside ? (outside ? BuildVolume::ObjectState::Colliding : BuildVolume::ObjectState::Inside) : BuildVolume::ObjectState::Outside;
}
#endif
// Trim the input transformed triangle mesh with print bed and test the remaining vertices with is_inside callback.
// Return inside / colliding / outside state.
template<typename InsideFn>
BuildVolume::ObjectState object_state_templ(const indexed_triangle_set &its, const Transform3f &trafo, bool may_be_below_bed, InsideFn is_inside)
{
size_t num_inside = 0;
size_t num_above = 0;
bool inside = false;
bool outside = false;
static constexpr const auto world_min_z = float(-BuildVolume::SceneEpsilon);
if (may_be_below_bed)
{
// Slower test, needs to clip the object edges with the print bed plane.
// 1) Allocate transformed vertices with their position with respect to print bed surface.
std::vector<char> sides;
sides.reserve(its.vertices.size());
const auto sign = [](const stl_vertex& pt) { return pt.z() > world_min_z ? 1 : pt.z() < world_min_z ? -1 : 0; };
for (const stl_vertex &v : its.vertices) {
const stl_vertex pt = trafo * v;
const int s = sign(pt);
sides.emplace_back(s);
if (s >= 0) {
// Vertex above or on print bed surface. Test whether it is inside the build volume.
++ num_above;
if (is_inside(pt))
++ num_inside;
}
}
// 2) Calculate intersections of triangle edges with the build surface.
inside = num_inside > 0;
outside = num_inside < num_above;
if (num_above < its.vertices.size() && ! (inside && outside)) {
// Not completely above the build surface and status may still change by testing edges intersecting the build platform.
for (const stl_triangle_vertex_indices &tri : its.indices) {
const int s[3] = { sides[tri(0)], sides[tri(1)], sides[tri(2)] };
if (std::min(s[0], std::min(s[1], s[2])) < 0 && std::max(s[0], std::max(s[1], s[2])) > 0) {
// Some edge of this triangle intersects the build platform. Calculate the intersection.
int iprev = 2;
for (int iedge = 0; iedge < 3; ++ iedge) {
if (s[iprev] * s[iedge] == -1) {
// edge intersects the build surface. Calculate intersection point.
const stl_vertex p1 = trafo * its.vertices[tri(iprev)];
const stl_vertex p2 = trafo * its.vertices[tri(iedge)];
assert(sign(p1) == s[iprev]);
assert(sign(p2) == s[iedge]);
assert(p1.z() * p2.z() < 0);
// Edge crosses the z plane. Calculate intersection point with the plane.
const float t = (world_min_z - p1.z()) / (p2.z() - p1.z());
(is_inside(Vec3f(p1.x() + (p2.x() - p1.x()) * t, p1.y() + (p2.y() - p1.y()) * t, world_min_z)) ? inside : outside) = true;
}
iprev = iedge;
}
if (inside && outside)
break;
}
}
}
}
else
{
// Much simpler and faster code, not clipping the object with the print bed.
assert(! may_be_below_bed);
num_above = its.vertices.size();
for (const stl_vertex &v : its.vertices) {
const stl_vertex pt = trafo * v;
assert(pt.z() >= world_min_z);
if (is_inside(pt))
++ num_inside;
}
inside = num_inside > 0;
outside = num_inside < num_above;
}
return inside ? (outside ? BuildVolume::ObjectState::Colliding : BuildVolume::ObjectState::Inside) : BuildVolume::ObjectState::Outside;
}
BuildVolume::ObjectState BuildVolume::object_state(const indexed_triangle_set &its, const Transform3f &trafo, bool may_be_below_bed) const
{
switch (m_type) {
case Type::Rectangle:
{
BoundingBox3Base<Vec3d> build_volume = this->bounding_volume().inflated(SceneEpsilon);
BoundingBox3Base<Vec3f> build_volumef(build_volume.min.cast<float>(), build_volume.max.cast<float>());
if (m_max_print_height == 0)
build_volume.max.z() = std::numeric_limits<double>::max();
// The following test correctly interprets intersection of a non-convex object with a rectangular build volume.
//return rectangle_test(its, trafo, to_2d(build_volume.min), to_2d(build_volume.max), build_volume.max.z());
//FIXME This test does NOT correctly interprets intersection of a non-convex object with a rectangular build volume.
return object_state_templ(its, trafo, may_be_below_bed, [build_volumef](const Vec3f &pt) { return build_volumef.contains(pt); });
}
case Type::Circle:
{
Geometry::Circlef circle { unscaled<float>(m_circle.center), unscaled<float>(m_circle.radius + SceneEpsilon) };
return m_max_print_height == 0 ?
object_state_templ(its, trafo, may_be_below_bed, [circle](const Vec3f &pt) { return circle.contains(to_2d(pt)); }) :
object_state_templ(its, trafo, may_be_below_bed, [circle, z = m_max_print_height + SceneEpsilon](const Vec3f &pt) { return pt.z() < z && circle.contains(to_2d(pt)); });
}
case Type::Convex:
//FIXME doing test on convex hull until we learn to do test on non-convex polygons efficiently.
case Type::Custom:
return m_max_print_height == 0 ?
object_state_templ(its, trafo, may_be_below_bed, [this](const Vec3f &pt) { return Geometry::inside_convex_polygon(m_top_bottom_convex_hull_decomposition_scene, to_2d(pt).cast<double>()); }) :
object_state_templ(its, trafo, may_be_below_bed, [this, z = m_max_print_height + SceneEpsilon](const Vec3f &pt) { return pt.z() < z && Geometry::inside_convex_polygon(m_top_bottom_convex_hull_decomposition_scene, to_2d(pt).cast<double>()); });
case Type::Invalid:
default:
return ObjectState::Inside;
}
}
BuildVolume::ObjectState BuildVolume::volume_state_bbox(const BoundingBoxf3 &volume_bbox) const
{
assert(m_type == Type::Rectangle);
BoundingBox3Base<Vec3d> build_volume = this->bounding_volume().inflated(SceneEpsilon);
if (m_max_print_height == 0)
build_volume.max.z() = std::numeric_limits<double>::max();
return build_volume.contains(volume_bbox) ? ObjectState::Inside : build_volume.intersects(volume_bbox) ? ObjectState::Colliding : ObjectState::Outside;
}
bool BuildVolume::all_paths_inside(const GCodeProcessorResult &paths, const BoundingBoxf3 &paths_bbox) const
{
auto move_valid = [](const GCodeProcessorResult::MoveVertex &move) {
return move.type == EMoveType::Extrude && move.extrusion_role != erCustom && move.width != 0.f && move.height != 0.f;
};
static constexpr const double epsilon = BedEpsilon;
switch (m_type) {
case Type::Rectangle:
{
BoundingBox3Base<Vec3d> build_volume = this->bounding_volume().inflated(epsilon);
if (m_max_print_height == 0)
build_volume.max.z() = std::numeric_limits<double>::max();
return build_volume.contains(paths_bbox);
}
case Type::Circle:
{
const Vec2f c = unscaled<float>(m_circle.center);
const float r = unscaled<double>(m_circle.radius) + epsilon;
const float r2 = sqr(r);
return m_max_print_height == 0 ?
std::all_of(paths.moves.begin(), paths.moves.end(), [move_valid, c, r2](const GCodeProcessorResult::MoveVertex &move)
{ return ! move_valid(move) || (to_2d(move.position) - c).squaredNorm() <= r2; }) :
std::all_of(paths.moves.begin(), paths.moves.end(), [move_valid, c, r2, z = m_max_print_height + epsilon](const GCodeProcessorResult::MoveVertex& move)
{ return ! move_valid(move) || ((to_2d(move.position) - c).squaredNorm() <= r2 && move.position.z() <= z); });
}
case Type::Convex:
//FIXME doing test on convex hull until we learn to do test on non-convex polygons efficiently.
case Type::Custom:
return m_max_print_height == 0 ?
std::all_of(paths.moves.begin(), paths.moves.end(), [move_valid, this](const GCodeProcessorResult::MoveVertex &move)
{ return ! move_valid(move) || Geometry::inside_convex_polygon(m_top_bottom_convex_hull_decomposition_bed, to_2d(move.position).cast<double>()); }) :
std::all_of(paths.moves.begin(), paths.moves.end(), [move_valid, this, z = m_max_print_height + epsilon](const GCodeProcessorResult::MoveVertex &move)
{ return ! move_valid(move) || (Geometry::inside_convex_polygon(m_top_bottom_convex_hull_decomposition_bed, to_2d(move.position).cast<double>()) && move.position.z() <= z); });
default:
return true;
}
}
template<typename Fn>
inline bool all_inside_vertices_normals_interleaved(const std::vector<float> &paths, Fn fn)
{
for (auto it = paths.begin(); it != paths.end(); ) {
it += 3;
if (! fn({ *it, *(it + 1), *(it + 2) }))
return false;
it += 3;
}
return true;
}
bool BuildVolume::all_paths_inside_vertices_and_normals_interleaved(const std::vector<float> &paths, const Eigen::AlignedBox<float, 3> &paths_bbox) const
{
assert(paths.size() % 6 == 0);
static constexpr const double epsilon = BedEpsilon;
switch (m_type) {
case Type::Rectangle:
{
BoundingBox3Base<Vec3d> build_volume = this->bounding_volume().inflated(epsilon);
if (m_max_print_height == 0)
build_volume.max.z() = std::numeric_limits<double>::max();
return build_volume.contains(paths_bbox.min().cast<double>()) && build_volume.contains(paths_bbox.max().cast<double>());
}
case Type::Circle:
{
const Vec2f c = unscaled<float>(m_circle.center);
const float r = unscaled<double>(m_circle.radius) + float(epsilon);
const float r2 = sqr(r);
return m_max_print_height == 0 ?
all_inside_vertices_normals_interleaved(paths, [c, r2](Vec3f p) { return (to_2d(p) - c).squaredNorm() <= r2; }) :
all_inside_vertices_normals_interleaved(paths, [c, r2, z = m_max_print_height + epsilon](Vec3f p) { return (to_2d(p) - c).squaredNorm() <= r2 && p.z() <= z; });
}
case Type::Convex:
//FIXME doing test on convex hull until we learn to do test on non-convex polygons efficiently.
case Type::Custom:
return m_max_print_height == 0 ?
all_inside_vertices_normals_interleaved(paths, [this](Vec3f p) { return Geometry::inside_convex_polygon(m_top_bottom_convex_hull_decomposition_bed, to_2d(p).cast<double>()); }) :
all_inside_vertices_normals_interleaved(paths, [this, z = m_max_print_height + epsilon](Vec3f p) { return Geometry::inside_convex_polygon(m_top_bottom_convex_hull_decomposition_bed, to_2d(p).cast<double>()) && p.z() <= z; });
default:
return true;
}
}
std::string_view BuildVolume::type_name(Type type)
{
using namespace std::literals;
switch (type) {
case Type::Invalid: return "Invalid"sv;
case Type::Rectangle: return "Rectangle"sv;
case Type::Circle: return "Circle"sv;
case Type::Convex: return "Convex"sv;
case Type::Custom: return "Custom"sv;
}
// make visual studio happy
assert(false);
return {};
}
} // namespace Slic3r
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