Merge branch 'master_27x' of https://github.com/Prusa-Development/PrusaSlicerPrivate into master_27x

src/libslic3r/SupportSpotsGenerator.cpp

@@ -154,26 +154,69 @@ void SliceConnection::print_info(const std::string &tag) const
     std::cout << "covariance: " << covariance << std::endl;
 }
 
-Integrals::Integrals (const Polygons& polygons) {
+Integrals::Integrals(const Polygon &polygon)
+{
+    if (polygon.points.size() < 3) {
+        assert(false && "Polygon is expected to have non-zero area!");
+        *this = Integrals{};
+        return;
+    }
+    Vec2f p0 = unscaled(polygon.first_point()).cast<float>();
+    for (size_t i = 2; i < polygon.points.size(); i++) {
+        Vec2f p1 = unscaled(polygon.points[i - 1]).cast<float>();
+        Vec2f p2 = unscaled(polygon.points[i]).cast<float>();
+
+        float sign = cross2(p1 - p0, p2 - p1) > 0 ? 1.0f : -1.0f;
+
+        auto [area, first_moment_of_area, second_moment_area,
+              second_moment_of_area_covariance] = compute_moments_of_area_of_triangle(p0, p1, p2);
+
+        this->area += sign * area;
+        this->x_i += sign * first_moment_of_area;
+        this->x_i_squared += sign * second_moment_area;
+        this->xy += sign * second_moment_of_area_covariance;
+    }
+}
+
+Integrals::Integrals(const Polygons &polygons)
+{
     for (const Polygon &polygon : polygons) {
-        Vec2f p0 = unscaled(polygon.first_point()).cast<float>();
+        *this = *this + Integrals{polygon};
-        for (size_t i = 2; i < polygon.points.size(); i++) {
+    }
-            Vec2f p1 = unscaled(polygon.points[i - 1]).cast<float>();
+}
-            Vec2f p2 = unscaled(polygon.points[i]).cast<float>();
 
-            float sign = cross2(p1 - p0, p2 - p1) > 0 ? 1.0f : -1.0f;
+Integrals::Integrals(const Polylines& polylines, const std::vector<float>& widths) {
+    assert(extrusion_lines.size() == widths.size());
+    for (size_t i = 0; i < polylines.size(); ++i) {
+        Lines polyline{polylines[i].lines()};
+        float width{widths[i]};
+        for (const Line& line : polyline) {
+            Vec2f line_direction = unscaled(line.vector()).cast<float>();
+            Vec2f normal{line_direction.y(), -line_direction.x()};
+            normal.normalize();
 
-            auto [area, first_moment_of_area, second_moment_area,
+            Vec2f line_a = unscaled(line.a).cast<float>();
-                  second_moment_of_area_covariance] = compute_moments_of_area_of_triangle(p0, p1, p2);
+            Vec2f line_b = unscaled(line.b).cast<float>();
+            Vec2crd a = scaled(Vec2f{line_a + normal * width/2});
+            Vec2crd b = scaled(Vec2f{line_b + normal * width/2});
+            Vec2crd c = scaled(Vec2f{line_b - normal * width/2});
+            Vec2crd d = scaled(Vec2f{line_a - normal * width/2});
 
-            this->area += sign * area;
+            const Polygon ractangle({a, b, c, d});
-            this->x_i += sign * first_moment_of_area;
+            Integrals integrals{ractangle};
-            this->x_i_squared += sign * second_moment_area;
+            *this = *this + integrals;
-            this->xy += sign * second_moment_of_area_covariance;
         }
     }
 }
 
+Integrals::Integrals(float area, Vec2f x_i, Vec2f x_i_squared, float xy)
+    : area(area), x_i(std::move(x_i)), x_i_squared(std::move(x_i_squared)), xy(xy)
+{}
+
+Integrals operator+(const Integrals &a, const Integrals &b)
+{
+    return Integrals{a.area + b.area, a.x_i + b.x_i, a.x_i_squared + b.x_i_squared, a.xy + b.xy};
+}
 
 SliceConnection estimate_slice_connection(size_t slice_idx, const Layer *layer)
 {
@@ -473,18 +516,50 @@ ObjectPart::ObjectPart(
             continue;
         }
 
-        const Polygons polygons{collection->polygons_covered_by_width()};
+        for (const ExtrusionEntity* entity: collection->flatten()) {
+            Polylines polylines;
+            std::vector<float> widths;
 
-        const Integrals integrals{polygons};
+            if (
-        const float volume = integrals.area * layer_height;
+                const auto* path = dynamic_cast<const ExtrusionPath*>(entity);
-        this->volume += volume;
+                path != nullptr
-        this->volume_centroid_accumulator += to_3d(integrals.x_i, center_z * integrals.area) / integrals.area * volume;
+            ) {
+                polylines.push_back(path->as_polyline());
+                widths.push_back(path->width());
+            } else if (
+                const auto* loop = dynamic_cast<const ExtrusionLoop*>(entity);
+                loop != nullptr
+            ) {
+                for (const ExtrusionPath& path : loop->paths) {
+                    polylines.push_back(path.as_polyline());
+                    widths.push_back(path.width());
+                }
+            } else if (
+                const auto* multi_path = dynamic_cast<const ExtrusionMultiPath*>(entity);
+                multi_path != nullptr
+            ) {
+                for (const ExtrusionPath& path : multi_path->paths) {
+                    polylines.push_back(path.as_polyline());
+                    widths.push_back(path.width());
+                }
+            } else {
+                throw std::runtime_error(
+                    "Failed to construct object part from extrusions!"
+                    " Unknown extrusion type."
+                );
+            }
 
-        if (this->connected_to_bed) {
+            const Integrals integrals{polylines, widths};
-            this->sticking_area += integrals.area;
+            const float volume = integrals.area * layer_height;
-            this->sticking_centroid_accumulator += to_3d(integrals.x_i, bottom_z * integrals.area);
+            this->volume += volume;
-            this->sticking_second_moment_of_area_accumulator += integrals.x_i_squared;
+            this->volume_centroid_accumulator += to_3d(integrals.x_i, center_z * integrals.area) / integrals.area * volume;
-            this->sticking_second_moment_of_area_covariance_accumulator += integrals.xy;
+
+            if (this->connected_to_bed) {
+                this->sticking_area += integrals.area;
+                this->sticking_centroid_accumulator += to_3d(integrals.x_i, bottom_z * integrals.area);
+                this->sticking_second_moment_of_area_accumulator += integrals.x_i_squared;
+                this->sticking_second_moment_of_area_covariance_accumulator += integrals.xy;
+            }
         }
     }
 

src/libslic3r/SupportSpotsGenerator.hpp

@@ -151,16 +151,28 @@ class Integrals{
      * @param polygons List of polygons specifing the domain.
      */
     explicit Integrals(const Polygons& polygons);
+    explicit Integrals(const Polygon& polygon);
+    /**
+     * Construct integral x_i int x_i^2 (i=1,2), xy and integral 1 (area) over
+     * a set of rectangles defined by a "thick" polyline.
+     */
+    explicit Integrals(const Polylines& polylines, const std::vector<float>& widths);
 
     // TODO refactor and delete the default constructor
     Integrals() = default;
+    Integrals(float area, Vec2f x_i, Vec2f x_i_squared, float xy);
 
     float area{};
     Vec2f x_i{Vec2f::Zero()};
     Vec2f x_i_squared{Vec2f::Zero()};
     float xy{};
+
+private:
+    void add(const Integrals& other);
 };
 
+Integrals operator+(const Integrals& a, const Integrals& b);
+
 float compute_second_moment(
     const Integrals& integrals,
     const Vec2f& axis_direction

tests/libslic3r/test_support_spots_generator.cpp

@@ -5,23 +5,44 @@
 using namespace Slic3r;
 using namespace SupportSpotsGenerator;
 
+namespace Rectangle {
+const float width = 10;
+const float height = 20;
+const Polygon polygon = {
+    scaled(Vec2f{-width / 2, -height / 2}),
+    scaled(Vec2f{width / 2, -height / 2}),
+    scaled(Vec2f{width / 2, height / 2}),
+    scaled(Vec2f{-width / 2, height / 2})
+};
+}
 
-TEST_CASE("Numerical integral calculation compared with exact solution.", "[SupportSpotsGenerator]") {
+TEST_CASE("Numerical integral over polygon calculation compared with exact solution.", "[SupportSpotsGenerator]") {
-    const float width = 10;
+    const Integrals integrals{Rectangle::polygon};
-    const float height = 20;
-    const Polygon polygon = {
-        scaled(Vec2f{-width / 2, -height / 2}),
-        scaled(Vec2f{width / 2, -height / 2}),
-        scaled(Vec2f{width / 2, height / 2}),
-        scaled(Vec2f{-width / 2, height / 2})
-    };
 
-    const Integrals integrals{{polygon}};
+    CHECK(integrals.area == Approx(Rectangle::width * Rectangle::height));
-    CHECK(integrals.area == Approx(width * height));
     CHECK(integrals.x_i.x() == Approx(0));
     CHECK(integrals.x_i.y() == Approx(0));
-    CHECK(integrals.x_i_squared.x() == Approx(std::pow(width, 3) * height / 12));
+    CHECK(integrals.x_i_squared.x() == Approx(std::pow(Rectangle::width, 3) * Rectangle::height / 12));
-    CHECK(integrals.x_i_squared.y() == Approx(width * std::pow(height, 3) / 12));
+    CHECK(integrals.x_i_squared.y() == Approx(Rectangle::width * std::pow(Rectangle::height, 3) / 12));
+}
+
+TEST_CASE("Integrals over multiple polygons", "[SupportSpotsGenerator]") {
+    const Integrals integrals{{Rectangle::polygon, Rectangle::polygon}};
+
+    CHECK(integrals.area == Approx(2 * Rectangle::width * Rectangle::height));
+}
+
+TEST_CASE("Numerical integral over line calculation compared with exact solution.", "[SupportSpotsGenerator]") {
+    const float length = 10;
+    const float width = 20;
+    const Polyline polyline{scaled(Vec2f{-length/2.0f, 0.0f}), scaled(Vec2f{length/2.0f, 0.0f})};
+
+    const Integrals integrals{{polyline}, {width}};
+    CHECK(integrals.area == Approx(length * width));
+    CHECK(integrals.x_i.x() == Approx(0));
+    CHECK(integrals.x_i.y() == Approx(0));
+    CHECK(integrals.x_i_squared.x() == Approx(std::pow(length, 3) * width / 12));
+    CHECK(integrals.x_i_squared.y() == Approx(length * std::pow(width, 3) / 12));
 }
 
 TEST_CASE("Moment values and ratio check.", "[SupportSpotsGenerator]") {
@@ -37,7 +58,7 @@ TEST_CASE("Moment values and ratio check.", "[SupportSpotsGenerator]") {
         scaled(Vec2f{0, height})
     };
 
-    const Integrals integrals{{polygon}};
+    const Integrals integrals{polygon};
 
     const Vec2f x_axis{1, 0};
     const float x_axis_moment = compute_second_moment(integrals, x_axis);
@@ -55,7 +76,6 @@ TEST_CASE("Moment values and ratio check.", "[SupportSpotsGenerator]") {
 }
 
 TEST_CASE("Moments calculation for rotated axis.", "[SupportSpotsGenerator]") {
-
     Polygon polygon = {
         scaled(Vec2f{6.362284076172198, 138.9674202217155}),
         scaled(Vec2f{97.48779843751677, 106.08136606617076}),
@@ -69,7 +89,7 @@ TEST_CASE("Moments calculation for rotated axis.", "[SupportSpotsGenerator]") {
         scaled(Vec2f{77.56229640885199, 189.33057746591336})
     };
 
-    Integrals integrals{{polygon}};
+    Integrals integrals{polygon};
 
     // Meassured counterclockwise from (1, 0)
     const float angle = 1.432f;
@@ -130,7 +150,7 @@ TEST_CASE_METHOD(ObjectPartFixture, "Constructing ObjectPart using extrusion col
         std::nullopt
     };
 
-    Integrals expected{{expected_polygon}};
+    Integrals expected{expected_polygon};
 
     CHECK(part.connected_to_bed == true);
     Vec3f volume_centroid{part.volume_centroid_accumulator / part.volume};