NEW: path planning algorithm

Astar.hpp, JumpPointSearch.hpp and JumpPointSearch.cpp are from Prusa.

Github: 1793

Signed-off-by: wenjie.guo <wenjie.guo@bambulab.com>

Original Authors:
tamasmeszaros <meszaros.q@gmail.com>,
Pavel Mikus <pavel.mikus.mail@seznam.cz>

Change-Id: I72f68d59bc8bb3b7cc0f37276c10811bca2ac38c
(cherry picked from commit 7a14a6a48af68b6a3d7985bdb9c171aabeb70817)
This commit is contained in:
wenjie.guo 2023-09-25 10:40:12 +08:00 committed by Lane.Wei
parent ccefbfe936
commit d3db1f2537
5 changed files with 548 additions and 1 deletions

157
src/libslic3r/AStar.hpp Normal file
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@ -0,0 +1,157 @@
#ifndef ASTAR_HPP
#define ASTAR_HPP
#include <cmath> // std::isinf() is here
#include <unordered_map>
#include "libslic3r/MutablePriorityQueue.hpp"
namespace Slic3r { namespace astar {
// Borrowed from C++20
template<class T> using remove_cvref_t = std::remove_cv_t<std::remove_reference_t<T>>;
// Input interface for the Astar algorithm. Specialize this struct for a
// particular type and implement all the 4 methods and specify the Node type
// to register the new type for the astar implementation.
template<class T> struct TracerTraits_
{
// The type of a node used by this tracer. Usually a point in space.
using Node = typename T::Node;
// Call fn for every new node reachable from node 'src'. fn should have the
// candidate node as its only argument.
template<class Fn> static void foreach_reachable(const T &tracer, const Node &src, Fn &&fn) { tracer.foreach_reachable(src, fn); }
// Get the distance from node 'a' to node 'b'. This is sometimes referred
// to as the g value of a node in AStar context.
static float distance(const T &tracer, const Node &a, const Node &b) { return tracer.distance(a, b); }
// Get the estimated distance heuristic from node 'n' to the destination.
// This is referred to as the h value in AStar context.
// If node 'n' is the goal, this function should return a negative value.
// Note that this heuristic should be admissible (never bigger than the real
// cost) in order for Astar to work.
static float goal_heuristic(const T &tracer, const Node &n) { return tracer.goal_heuristic(n); }
// Return a unique identifier (hash) for node 'n'.
static size_t unique_id(const T &tracer, const Node &n) { return tracer.unique_id(n); }
};
// Helper definition to get the node type of a tracer
template<class T> using TracerNodeT = typename TracerTraits_<remove_cvref_t<T>>::Node;
constexpr auto Unassigned = std::numeric_limits<size_t>::max();
template<class Tracer> struct QNode // Queue node. Keeps track of scores g, and h
{
TracerNodeT<Tracer> node; // The actual node itself
size_t queue_id; // Position in the open queue or Unassigned if closed
size_t parent; // unique id of the parent or Unassigned
float g, h;
float f() const { return g + h; }
QNode(TracerNodeT<Tracer> n = {}, size_t p = Unassigned, float gval = std::numeric_limits<float>::infinity(), float hval = 0.f)
: node{std::move(n)}, parent{p}, queue_id{InvalidQueueID}, g{gval}, h{hval}
{}
};
// Run the AStar algorithm on a tracer implementation.
// The 'tracer' argument encapsulates the domain (grid, point cloud, etc...)
// The 'source' argument is the starting node.
// The 'out' argument is the output iterator into which the output nodes are
// written. For performance reasons, the order is reverse, from the destination
// to the source -- (destination included, source is not).
// The 'cached_nodes' argument is an optional associative container to hold a
// QNode entry for each visited node. Any compatible container can be used
// (like std::map or maps with different allocators, even a sufficiently large
// std::vector).
//
// Note that no destination node is given in the signature. The tracer's
// goal_heuristic() method should return a negative value if a node is a
// destination node.
template<class Tracer, class It, class NodeMap = std::unordered_map<size_t, QNode<Tracer>>>
bool search_route(const Tracer &tracer, const TracerNodeT<Tracer> &source, It out, NodeMap &&cached_nodes = {})
{
using Node = TracerNodeT<Tracer>;
using QNode = QNode<Tracer>;
using TracerTraits = TracerTraits_<remove_cvref_t<Tracer>>;
struct LessPred
{ // Comparison functor needed by the priority queue
NodeMap &m;
bool operator()(size_t node_a, size_t node_b) { return m[node_a].f() < m[node_b].f(); }
};
auto qopen = make_mutable_priority_queue<size_t, true>([&cached_nodes](size_t el, size_t qidx) { cached_nodes[el].queue_id = qidx; }, LessPred{cached_nodes});
QNode initial{source, /*parent = */ Unassigned, /*g = */ 0.f};
size_t source_id = TracerTraits::unique_id(tracer, source);
cached_nodes[source_id] = initial;
qopen.push(source_id);
size_t goal_id = TracerTraits::goal_heuristic(tracer, source) < 0.f ? source_id : Unassigned;
while (goal_id == Unassigned && !qopen.empty()) {
size_t q_id = qopen.top();
qopen.pop();
QNode &q = cached_nodes[q_id];
// This should absolutely be initialized in the cache already
assert(!std::isinf(q.g));
TracerTraits::foreach_reachable(tracer, q.node, [&](const Node &succ_nd) {
if (goal_id != Unassigned) return true;
float h = TracerTraits::goal_heuristic(tracer, succ_nd);
float dst = TracerTraits::distance(tracer, q.node, succ_nd);
size_t succ_id = TracerTraits::unique_id(tracer, succ_nd);
QNode qsucc_nd{succ_nd, q_id, q.g + dst, h};
if (h < 0.f) {
goal_id = succ_id;
cached_nodes[succ_id] = qsucc_nd;
} else {
// If succ_id is not in cache, it gets created with g = infinity
QNode &prev_nd = cached_nodes[succ_id];
if (qsucc_nd.g < prev_nd.g) {
// new route is better, apply it:
// Save the old queue id, it would be lost after the next line
size_t queue_id = prev_nd.queue_id;
// The cache needs to be updated either way
prev_nd = qsucc_nd;
if (queue_id == InvalidQueueID)
// was in closed or unqueued, rescheduling
qopen.push(succ_id);
else // was in open, updating
qopen.update(queue_id);
}
}
return goal_id != Unassigned;
});
}
// Write the output, do not reverse. Clients can do so if they need to.
if (goal_id != Unassigned) {
const QNode *q = &cached_nodes[goal_id];
while (q->parent != Unassigned) {
assert(!std::isinf(q->g)); // Uninitialized nodes are NOT allowed
*out = q->node;
++out;
q = &cached_nodes[q->parent];
}
}
return goal_id != Unassigned;
}
}} // namespace Slic3r::astar
#endif // ASTAR_HPP

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@ -27,6 +27,7 @@ set(lisbslic3r_sources
AABBMesh.hpp AABBMesh.hpp
AABBMesh.cpp AABBMesh.cpp
AnyPtr.hpp AnyPtr.hpp
AStar.hpp
BoundingBox.cpp BoundingBox.cpp
BoundingBox.hpp BoundingBox.hpp
BridgeDetector.cpp BridgeDetector.cpp
@ -177,6 +178,8 @@ set(lisbslic3r_sources
Int128.hpp Int128.hpp
InternalBridgeDetector.cpp InternalBridgeDetector.cpp
InternalBridgeDetector.hpp InternalBridgeDetector.hpp
JumpPointSearch.hpp
JumpPointSearch.cpp
KDTreeIndirect.hpp KDTreeIndirect.hpp
Layer.cpp Layer.cpp
Layer.hpp Layer.hpp

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@ -0,0 +1,349 @@
#include "JumpPointSearch.hpp"
#include "BoundingBox.hpp"
#include "ExPolygon.hpp"
#include "Point.hpp"
#include "libslic3r/AStar.hpp"
#include "libslic3r/KDTreeIndirect.hpp"
#include "libslic3r/Polygon.hpp"
#include "libslic3r/Polyline.hpp"
#include "libslic3r/libslic3r.h"
#include <algorithm>
#include <cmath>
#include <cstddef>
#include <cstdint>
#include <cstdlib>
#include <iterator>
#include <limits>
#include <optional>
#include <string>
#include <unordered_map>
#include <vector>
#include <oneapi/tbb/scalable_allocator.h>
//#define DEBUG_FILES
#ifdef DEBUG_FILES
#include "libslic3r/SVG.hpp"
#endif
namespace Slic3r {
// execute fn for each pixel on the line. If fn returns false, terminate the iteration
template<typename PointFn> void dda(coord_t x0, coord_t y0, coord_t x1, coord_t y1, const PointFn &fn)
{
coord_t dx = abs(x1 - x0);
coord_t dy = abs(y1 - y0);
coord_t x = x0;
coord_t y = y0;
coord_t n = 1 + dx + dy;
coord_t x_inc = (x1 > x0) ? 1 : -1;
coord_t y_inc = (y1 > y0) ? 1 : -1;
coord_t error = dx - dy;
dx *= 2;
dy *= 2;
for (; n > 0; --n) {
if (!fn(x, y)) return;
if (error > 0) {
x += x_inc;
error -= dy;
} else {
y += y_inc;
error += dx;
}
}
}
// will draw the line twice, second time with and offset of 1 in the direction of normal
// may call the fn on the same coordiantes multiple times!
template<typename PointFn> void double_dda_with_offset(coord_t x0, coord_t y0, coord_t x1, coord_t y1, const PointFn &fn)
{
Vec2d normal = Point{y1 - y0, x1 - x0}.cast<double>().normalized();
normal.x() = ceil(normal.x());
normal.y() = ceil(normal.y());
Point start_offset = Point(x0, y0) + (normal).cast<coord_t>();
Point end_offset = Point(x1, y1) + (normal).cast<coord_t>();
dda(x0, y0, x1, y1, fn);
dda(start_offset.x(), start_offset.y(), end_offset.x(), end_offset.y(), fn);
}
template<typename CellPositionType, typename CellQueryFn> class JPSTracer
{
public:
// Use incoming_dir [0,0] for starting points, so that all directions are checked from that point
struct Node
{
CellPositionType position;
CellPositionType incoming_dir;
};
JPSTracer(CellPositionType target, CellQueryFn is_passable) : target(target), is_passable(is_passable) {}
private:
CellPositionType target;
CellQueryFn is_passable; // should return boolean whether the cell is passable or not
CellPositionType find_jump_point(CellPositionType start, CellPositionType forward_dir) const
{
CellPositionType next = start + forward_dir;
while (next != target && is_passable(next) && !(is_jump_point(next, forward_dir))) { next = next + forward_dir; }
if (is_passable(next)) {
return next;
} else {
return start;
}
}
bool is_jump_point(CellPositionType pos, CellPositionType forward_dir) const
{
if (abs(forward_dir.x()) + abs(forward_dir.y()) == 2) {
// diagonal
CellPositionType horizontal_check_dir = CellPositionType{forward_dir.x(), 0};
CellPositionType vertical_check_dir = CellPositionType{0, forward_dir.y()};
if (!is_passable(pos - horizontal_check_dir) && is_passable(pos + forward_dir - 2 * horizontal_check_dir)) { return true; }
if (!is_passable(pos - vertical_check_dir) && is_passable(pos + forward_dir - 2 * vertical_check_dir)) { return true; }
if (find_jump_point(pos, horizontal_check_dir) != pos) { return true; }
if (find_jump_point(pos, vertical_check_dir) != pos) { return true; }
return false;
} else { // horizontal or vertical
CellPositionType side_dir = CellPositionType(forward_dir.y(), forward_dir.x());
if (!is_passable(pos + side_dir) && is_passable(pos + forward_dir + side_dir)) { return true; }
if (!is_passable(pos - side_dir) && is_passable(pos + forward_dir - side_dir)) { return true; }
return false;
}
}
public:
template<class Fn> void foreach_reachable(const Node &from, Fn &&fn) const
{
const CellPositionType & pos = from.position;
const CellPositionType & forward_dir = from.incoming_dir;
std::vector<CellPositionType> dirs_to_check{};
if (abs(forward_dir.x()) + abs(forward_dir.y()) == 0) { // special case for starting point
dirs_to_check = all_directions;
} else if (abs(forward_dir.x()) + abs(forward_dir.y()) == 2) {
// diagonal
CellPositionType horizontal_check_dir = CellPositionType{forward_dir.x(), 0};
CellPositionType vertical_check_dir = CellPositionType{0, forward_dir.y()};
if (!is_passable(pos - horizontal_check_dir) && is_passable(pos + forward_dir - 2 * horizontal_check_dir)) {
dirs_to_check.push_back(forward_dir - 2 * horizontal_check_dir);
}
if (!is_passable(pos - vertical_check_dir) && is_passable(pos + forward_dir - 2 * vertical_check_dir)) {
dirs_to_check.push_back(forward_dir - 2 * vertical_check_dir);
}
dirs_to_check.push_back(horizontal_check_dir);
dirs_to_check.push_back(vertical_check_dir);
dirs_to_check.push_back(forward_dir);
} else { // horizontal or vertical
CellPositionType side_dir = CellPositionType(forward_dir.y(), forward_dir.x());
if (!is_passable(pos + side_dir) && is_passable(pos + forward_dir + side_dir)) { dirs_to_check.push_back(forward_dir + side_dir); }
if (!is_passable(pos - side_dir) && is_passable(pos + forward_dir - side_dir)) { dirs_to_check.push_back(forward_dir - side_dir); }
dirs_to_check.push_back(forward_dir);
}
for (const CellPositionType &dir : dirs_to_check) {
CellPositionType jp = find_jump_point(pos, dir);
if (jp != pos) fn(Node{jp, dir});
}
}
float distance(Node a, Node b) const { return (a.position - b.position).template cast<double>().norm(); }
float goal_heuristic(Node n) const { return n.position == target ? -1.f : (target - n.position).template cast<double>().norm(); }
size_t unique_id(Node n) const { return (static_cast<size_t>(uint16_t(n.position.x())) << 16) + static_cast<size_t>(uint16_t(n.position.y())); }
const std::vector<CellPositionType> all_directions{{1, 0}, {1, 1}, {0, 1}, {-1, 1}, {-1, 0}, {-1, -1}, {0, -1}, {1, -1}};
};
void JPSPathFinder::clear()
{
inpassable.clear();
max_search_box.max = Pixel(std::numeric_limits<coord_t>::min(), std::numeric_limits<coord_t>::min());
max_search_box.min = Pixel(std::numeric_limits<coord_t>::max(), std::numeric_limits<coord_t>::max());
add_obstacles(bed_shape);
}
void JPSPathFinder::add_obstacles(const Lines &obstacles)
{
auto store_obstacle = [&](coord_t x, coord_t y) {
max_search_box.max.x() = std::max(max_search_box.max.x(), x);
max_search_box.max.y() = std::max(max_search_box.max.y(), y);
max_search_box.min.x() = std::min(max_search_box.min.x(), x);
max_search_box.min.y() = std::min(max_search_box.min.y(), y);
inpassable.insert(Pixel{x, y});
return true;
};
for (const Line &l : obstacles) {
Pixel start = pixelize(l.a);
Pixel end = pixelize(l.b);
double_dda_with_offset(start.x(), start.y(), end.x(), end.y(), store_obstacle);
}
}
Polyline JPSPathFinder::find_path(const Point &p0, const Point &p1)
{
Pixel start = pixelize(p0);
Pixel end = pixelize(p1);
if (inpassable.empty() || (start - end).cast<float>().norm() < 3.0) { return Polyline{p0, p1}; }
if (inpassable.find(start) != inpassable.end()) {
dda(start.x(), start.y(), end.x(), end.y(), [&](coord_t x, coord_t y) {
if (inpassable.find(Pixel(x, y)) == inpassable.end() || start == end) { // new start not found yet, and xy passable
start = Pixel(x, y);
return false;
}
return true;
});
}
if (inpassable.find(end) != inpassable.end()) {
dda(end.x(), end.y(), start.x(), start.y(), [&](coord_t x, coord_t y) {
if (inpassable.find(Pixel(x, y)) == inpassable.end() || start == end) { // new start not found yet, and xy passable
end = Pixel(x, y);
return false;
}
return true;
});
}
BoundingBox search_box = max_search_box;
search_box.max -= Pixel(1, 1);
search_box.min += Pixel(1, 1);
BoundingBox bounding_square(Points{start, end});
bounding_square.max += Pixel(5, 5);
bounding_square.min -= Pixel(5, 5);
coord_t bounding_square_size = 2 * std::max(bounding_square.size().x(), bounding_square.size().y());
bounding_square.max.x() += (bounding_square_size - bounding_square.size().x()) / 2;
bounding_square.min.x() -= (bounding_square_size - bounding_square.size().x()) / 2;
bounding_square.max.y() += (bounding_square_size - bounding_square.size().y()) / 2;
bounding_square.min.y() -= (bounding_square_size - bounding_square.size().y()) / 2;
// Intersection - limit the search box to a square area around the start and end, to fasten the path searching
search_box.max = search_box.max.cwiseMin(bounding_square.max);
search_box.min = search_box.min.cwiseMax(bounding_square.min);
auto cell_query = [&](Pixel pixel) { return search_box.contains(pixel) && (pixel == start || pixel == end || inpassable.find(pixel) == inpassable.end()); };
JPSTracer<Pixel, decltype(cell_query)> tracer(end, cell_query);
using QNode = astar::QNode<JPSTracer<Pixel, decltype(cell_query)>>;
std::unordered_map<size_t, QNode> astar_cache{};
std::vector<Pixel> out_path;
std::vector<decltype(tracer)::Node> out_nodes;
if (!astar::search_route(tracer, {start, {0, 0}}, std::back_inserter(out_nodes), astar_cache)) {
// path not found - just reconstruct the best path from astar cache.
// Note that astar_cache is NOT empty - at least the starting point should always be there
auto coordiante_func = [&astar_cache](size_t idx, size_t dim) { return float(astar_cache[idx].node.position[dim]); };
std::vector<size_t> keys;
keys.reserve(astar_cache.size());
for (const auto &pair : astar_cache) { keys.push_back(pair.first); }
KDTreeIndirect<2, float, decltype(coordiante_func)> kd_tree(coordiante_func, keys);
size_t closest_qnode = find_closest_point(kd_tree, end.cast<float>());
out_path.push_back(end);
while (closest_qnode != astar::Unassigned) {
out_path.push_back(astar_cache[closest_qnode].node.position);
closest_qnode = astar_cache[closest_qnode].parent;
}
} else {
for (const auto &node : out_nodes) { out_path.push_back(node.position); }
out_path.push_back(start);
}
#ifdef DEBUG_FILES
auto scaled_points = [](const Points &ps) {
Points r;
for (const Point &p : ps) { r.push_back(Point::new_scale(p.x(), p.y())); }
return r;
};
auto scaled_point = [](const Point &p) { return Point::new_scale(p.x(), p.y()); };
::Slic3r::SVG svg(debug_out_path(("path_jps" + std::to_string(print_z) + "_" + std::to_string(rand() % 1000)).c_str()).c_str(),
BoundingBox(scaled_point(search_box.min), scaled_point(search_box.max)));
for (const auto &p : inpassable) { svg.draw(scaled_point(p), "black", scale_(0.4)); }
for (const auto &qn : astar_cache) { svg.draw(scaled_point(qn.second.node.position), "blue", scale_(0.3)); }
svg.draw(Polyline(scaled_points(out_path)), "yellow", scale_(0.25));
svg.draw(scaled_point(end), "purple", scale_(0.4));
svg.draw(scaled_point(start), "green", scale_(0.4));
#endif
std::vector<Pixel> tmp_path;
tmp_path.reserve(out_path.size());
// Some path found, reverse and remove points that do not change direction
std::reverse(out_path.begin(), out_path.end());
{
tmp_path.push_back(out_path.front()); // first point
for (size_t i = 1; i < out_path.size() - 1; i++) {
if ((out_path[i] - out_path[i - 1]).cast<float>().normalized() != (out_path[i + 1] - out_path[i]).cast<float>().normalized()) { tmp_path.push_back(out_path[i]); }
}
tmp_path.push_back(out_path.back()); // last_point
out_path = tmp_path;
}
#ifdef DEBUG_FILES
svg.draw(Polyline(scaled_points(out_path)), "orange", scale_(0.20));
#endif
tmp_path.clear();
// remove redundant jump points - there are points that change direction but are not needed - this inefficiency arises from the
// usage of grid search The removal alg tries to find the longest Px Px+k path without obstacles. If Px Px+k+1 is blocked, it will
// insert the Px+k point to result and continue search from Px+k
{
tmp_path.push_back(out_path.front()); // first point
size_t index_of_last_stored_point = 0;
for (size_t i = 1; i < out_path.size(); i++) {
if (i - index_of_last_stored_point < 2) continue;
bool passable = true;
auto store_obstacle = [&](coord_t x, coord_t y) {
if (Pixel(x, y) != start && Pixel(x, y) != end && inpassable.find(Pixel(x, y)) != inpassable.end()) {
passable = false;
return false;
}
return true;
};
dda(tmp_path.back().x(), tmp_path.back().y(), out_path[i].x(), out_path[i].y(), store_obstacle);
if (!passable) {
tmp_path.push_back(out_path[i - 1]);
index_of_last_stored_point = i - 1;
}
}
tmp_path.push_back(out_path.back()); // last_point
out_path = tmp_path;
}
#ifdef DEBUG_FILES
svg.draw(Polyline(scaled_points(out_path)), "red", scale_(0.15));
svg.Close();
#endif
// before returing the path, transform it from pixels back to points.
// Also replace the first and last pixel by input points so that result path patches input params exactly.
for (Pixel &p : out_path) { p = unpixelize(p); }
out_path.front() = p0;
out_path.back() = p1;
return Polyline(out_path);
}
} // namespace Slic3r

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@ -0,0 +1,38 @@
#pragma once
#ifndef SRC_LIBSLIC3R_JUMPPOINTSEARCH_HPP_
#define SRC_LIBSLIC3R_JUMPPOINTSEARCH_HPP_
#include "BoundingBox.hpp"
#include "Polygon.hpp"
#include "libslic3r/Layer.hpp"
#include "libslic3r/Point.hpp"
#include "libslic3r/Polyline.hpp"
#include "libslic3r/libslic3r.h"
#include <unordered_map>
#include <unordered_set>
namespace Slic3r {
class JPSPathFinder
{
using Pixel = Point;
std::unordered_set<Pixel, PointHash> inpassable;
coordf_t print_z;
BoundingBox max_search_box;
Lines bed_shape;
const coord_t resolution = scaled(1.5);
Pixel pixelize(const Point &p) { return p / resolution; }
Point unpixelize(const Pixel &p) { return p * resolution; }
public:
JPSPathFinder() = default;
void init_bed_shape(const Points &bed_shape) { this->bed_shape = (to_lines(Polygon{bed_shape})); };
void clear();
void add_obstacles(const Lines &obstacles);
Polyline find_path(const Point &start, const Point &end);
};
} // namespace Slic3r
#endif /* SRC_LIBSLIC3R_JUMPPOINTSEARCH_HPP_ */

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@ -3,7 +3,7 @@
#include <assert.h> #include <assert.h>
#include <type_traits> #include <type_traits>
constexpr auto InvalidQueueID = std::numeric_limits<size_t>::max();
template<typename T, typename IndexSetter, typename LessPredicate, const bool ResetIndexWhenRemoved = false> template<typename T, typename IndexSetter, typename LessPredicate, const bool ResetIndexWhenRemoved = false>
class MutablePriorityQueue class MutablePriorityQueue
{ {