Ported some ModelObject methods from Perl to C++.

Added some utility functions to TriangleMesh, thanks to @alexrj
Some porting to C++ based on work by @alexrj.

lib/Slic3r/Model.pm

@@ -1,27 +1,8 @@
 # extends C++ class Slic3r::Model
 package Slic3r::Model;
 
-use File::Basename qw(basename);
 use List::Util qw(first max any);
 
-sub read_from_file {
-    my ($class, $input_file, $add_default_instances) = @_;
-    $add_default_instances //= 1;
-    
-    my $model = $input_file =~ /\.[sS][tT][lL]$/                    ? Slic3r::Model->load_stl(Slic3r::encode_path($input_file), basename($input_file))
-              : $input_file =~ /\.[oO][bB][jJ]$/                    ? Slic3r::Model->load_obj(Slic3r::encode_path($input_file), basename($input_file))
-              : $input_file =~ /\.[aA][mM][fF](\.[xX][mM][lL])?$/   ? Slic3r::Model->load_amf(Slic3r::encode_path($input_file))
-              : $input_file =~ /\.[pP][rR][uU][sS][aA]$/            ? Slic3r::Model->load_prus(Slic3r::encode_path($input_file))
-              : die "Input file must have .stl, .obj or .amf(.xml) extension\n";
-    
-    die "The supplied file couldn't be read because it's empty.\n"
-        if $model->objects_count == 0;
-    
-    $_->set_input_file($input_file) for @{$model->objects};
-    $model->add_default_instances if $add_default_instances;
-    return $model;
-}
-
 sub merge {
     my $class = shift;
     my @models = @_;
@@ -70,38 +51,6 @@ sub set_material {
     return $material;
 }
 
-sub print_info {
-    my $self = shift;
-    $_->print_info for @{$self->objects};
-}
-
-sub looks_like_multipart_object {
-    my ($self) = @_;
-    
-    return 0 if $self->objects_count == 1;
-    return 0 if any { $_->volumes_count > 1 } @{$self->objects};
-    return 0 if any { @{$_->config->get_keys} > 1 } @{$self->objects};
-    
-    my %heights = map { $_ => 1 } map $_->mesh->bounding_box->z_min, map @{$_->volumes}, @{$self->objects};
-    return scalar(keys %heights) > 1;
-}
-
-sub convert_multipart_object {
-    my ($self) = @_;
-    
-    my @objects = @{$self->objects};
-    my $object = $self->add_object(
-        input_file          => $objects[0]->input_file,
-    );
-    foreach my $v (map @{$_->volumes}, @objects) {
-        my $volume = $object->add_volume($v);
-        $volume->set_name($v->object->name);
-    }
-    $object->add_instance($_) for map @{$_->instances}, @objects;
-    
-    $self->delete_object($_) for reverse 0..($self->objects_count-2);
-}
-
 # Extends C++ class Slic3r::ModelMaterial
 package Slic3r::Model::Material;
 
@@ -113,7 +62,6 @@ sub apply {
 # Extends C++ class Slic3r::ModelObject
 package Slic3r::Model::Object;
 
-use File::Basename qw(basename);
 use List::Util qw(first sum);
 
 sub add_volume {
@@ -193,29 +141,4 @@ sub mesh_stats {
     return $self->volumes->[0]->mesh->stats;
 }
 
-sub print_info {
-    my $self = shift;
-    
-    printf "Info about %s:\n", basename($self->input_file);
-    printf "  size:              x=%.3f y=%.3f z=%.3f\n", @{$self->raw_mesh->bounding_box->size};
-    if (my $stats = $self->mesh_stats) {
-        printf "  number of facets:  %d\n", $stats->{number_of_facets};
-        printf "  number of shells:  %d\n", $stats->{number_of_parts};
-        printf "  volume:            %.3f\n", $stats->{volume};
-        if ($self->needed_repair) {
-            printf "  needed repair:     yes\n";
-            printf "  degenerate facets: %d\n", $stats->{degenerate_facets};
-            printf "  edges fixed:       %d\n", $stats->{edges_fixed};
-            printf "  facets removed:    %d\n", $stats->{facets_removed};
-            printf "  facets added:      %d\n", $stats->{facets_added};
-            printf "  facets reversed:   %d\n", $stats->{facets_reversed};
-            printf "  backwards edges:   %d\n", $stats->{backwards_edges};
-        } else {
-            printf "  needed repair:     no\n";
-        }
-    } else {
-        printf "  number of facets:  %d\n", scalar(map @{$_->facets}, grep !$_->modifier, @{$self->volumes});
-    }
-}
-
 1;

lib/Slic3r/Print.pm

@@ -64,6 +64,7 @@ sub process {
     Slic3r::trace(3, "Slicing process finished.")
 }
 
+# G-code export process, running at a background thread.
 sub export_gcode {
     my $self = shift;
     my %params = @_;

xs/src/libslic3r/Model.cpp

@@ -1,8 +1,16 @@
 #include "Model.hpp"
 #include "Geometry.hpp"
 
+#include "Format/AMF.hpp"
+#include "Format/OBJ.hpp"
+#include "Format/PRUS.hpp"
+#include "Format/STL.hpp"
+
 #include <float.h>
 
+#include <boost/algorithm/string/predicate.hpp>
+#include <boost/filesystem.hpp>
+
 namespace Slic3r {
 
 Model::Model(const Model &other)
@@ -28,10 +36,36 @@ void Model::swap(Model &other)
     std::swap(this->objects,    other.objects);
 }
 
-Model::~Model()
+Model Model::read_from_file(const std::string &input_file, bool add_default_instances)
 {
-    this->clear_objects();
+    Model model;
-    this->clear_materials();
+    
+    bool result = false;
+    if (boost::algorithm::iends_with(input_file, ".stl"))
+        result = load_stl(input_file.c_str(), &model);
+    else if (boost::algorithm::iends_with(input_file, ".obj"))
+        result = load_obj(input_file.c_str(), &model);
+    else if (boost::algorithm::iends_with(input_file, ".amf") ||
+               boost::algorithm::iends_with(input_file, ".amf.xml"))
+        result = load_amf(input_file.c_str(), &model);
+    else if (boost::algorithm::iends_with(input_file, ".prusa"))
+        result = load_prus(input_file.c_str(), &model);
+    else
+        throw std::runtime_error("Unknown file format. Input file must have .stl, .obj, .amf(.xml) or .prusa extension.");
+    
+    if (! result)
+        throw std::runtime_error("Loading of a model file failed.");
+
+    if (model.objects.empty())
+        throw std::runtime_error("The supplied file couldn't be read because it's empty");
+    
+    for (ModelObject *o : model.objects)
+        o->input_file = input_file;
+    
+    if (add_default_instances)
+        model.add_default_instances();
+
+    return model;
 }
 
 ModelObject* Model::add_object()
@@ -279,6 +313,45 @@ void Model::duplicate_objects_grid(size_t x, size_t y, coordf_t dist)
     }
 }
 
+bool Model::looks_like_multipart_object() const
+{
+    if (this->objects.size() <= 1)
+        return false;
+    double zmin = std::numeric_limits<double>::max();
+    for (const ModelObject *obj : this->objects) {
+        if (obj->volumes.size() > 1 || obj->config.keys().size() > 1)
+            return false;
+        for (const ModelVolume *vol : obj->volumes) {
+            double zmin_this = vol->mesh.bounding_box().min.z;
+            if (zmin == std::numeric_limits<double>::max())
+                zmin = zmin_this;
+            else if (std::abs(zmin - zmin_this) > EPSILON)
+                // The volumes don't share zmin.
+                return true;
+        }
+    }
+    return false;
+}
+
+void Model::convert_multipart_object()
+{
+    if (this->objects.empty())
+        return;
+    
+    ModelObject* object = this->add_object();
+    object->input_file = this->objects.front()->input_file;
+    
+    for (const ModelObject* o : this->objects)
+        for (const ModelVolume* v : o->volumes)
+            object->add_volume(*v)->name = o->name;
+
+    for (const ModelInstance* i : this->objects.front()->instances)
+        object->add_instance(*i);
+    
+    while (this->objects.size() > 1)
+        this->delete_object(0);
+}
+
 ModelObject::ModelObject(Model *model, const ModelObject &other, bool copy_volumes) :  
     name(other.name),
     input_file(other.input_file),
@@ -662,6 +735,48 @@ void ModelObject::split(ModelObjectPtrs* new_objects)
     return;
 }
 
+void ModelObject::print_info() const
+{
+    using namespace std;
+    cout << fixed;
+    cout << "[" << boost::filesystem::path(this->input_file).filename().string() << "]" << endl;
+    
+    TriangleMesh mesh = this->raw_mesh();
+    mesh.check_topology();
+    BoundingBoxf3 bb = mesh.bounding_box();
+    Sizef3 size = bb.size();
+    cout << "size_x = " << size.x << endl;
+    cout << "size_y = " << size.y << endl;
+    cout << "size_z = " << size.z << endl;
+    cout << "min_x = " << bb.min.x << endl;
+    cout << "min_y = " << bb.min.y << endl;
+    cout << "min_z = " << bb.min.z << endl;
+    cout << "max_x = " << bb.max.x << endl;
+    cout << "max_y = " << bb.max.y << endl;
+    cout << "max_z = " << bb.max.z << endl;
+    cout << "number_of_facets = " << mesh.stl.stats.number_of_facets  << endl;
+    cout << "manifold = "   << (mesh.is_manifold() ? "yes" : "no") << endl;
+    
+    mesh.repair();  // this calculates number_of_parts
+    if (mesh.needed_repair()) {
+        mesh.repair();
+        if (mesh.stl.stats.degenerate_facets > 0)
+            cout << "degenerate_facets = "  << mesh.stl.stats.degenerate_facets << endl;
+        if (mesh.stl.stats.edges_fixed > 0)
+            cout << "edges_fixed = "        << mesh.stl.stats.edges_fixed       << endl;
+        if (mesh.stl.stats.facets_removed > 0)
+            cout << "facets_removed = "     << mesh.stl.stats.facets_removed    << endl;
+        if (mesh.stl.stats.facets_added > 0)
+            cout << "facets_added = "       << mesh.stl.stats.facets_added      << endl;
+        if (mesh.stl.stats.facets_reversed > 0)
+            cout << "facets_reversed = "    << mesh.stl.stats.facets_reversed   << endl;
+        if (mesh.stl.stats.backwards_edges > 0)
+            cout << "backwards_edges = "    << mesh.stl.stats.backwards_edges   << endl;
+    }
+    cout << "number_of_parts =  " << mesh.stl.stats.number_of_parts << endl;
+    cout << "volume = "           << mesh.volume()                  << endl;
+}
+
 void ModelVolume::material_id(t_model_material_id material_id)
 {
     this->_material_id = material_id;

xs/src/libslic3r/Model.hpp

@@ -126,6 +126,9 @@ public:
     void cut(coordf_t z, Model* model) const;
     void split(ModelObjectPtrs* new_objects);
 
+    // Print object statistics to console.
+    void print_info() const;
+    
 private:        
     ModelObject(Model *model) : m_model(model),  m_bounding_box_valid(false), layer_height_profile_valid(false) {}
     ModelObject(Model *model, const ModelObject &other, bool copy_volumes = true);
@@ -232,7 +235,10 @@ public:
     Model(const Model &other);
     Model& operator= (Model other);
     void swap(Model &other);
-    ~Model();
+    ~Model() { this->clear_objects(); this->clear_materials(); }
+
+    static Model read_from_file(const std::string &input_file, bool add_default_instances = true);
+
     ModelObject* add_object();
     ModelObject* add_object(const char *name, const char *path, const TriangleMesh &mesh);
     ModelObject* add_object(const char *name, const char *path, TriangleMesh &&mesh);
@@ -259,6 +265,11 @@ public:
     void duplicate(size_t copies_num, coordf_t dist, const BoundingBoxf* bb = NULL);
     void duplicate_objects(size_t copies_num, coordf_t dist, const BoundingBoxf* bb = NULL);
     void duplicate_objects_grid(size_t x, size_t y, coordf_t dist);
+
+    bool looks_like_multipart_object() const;
+    void convert_multipart_object();
+
+    void print_info() const { for (const ModelObject *o : this->objects) o->print_info(); }
 };
 
 }

xs/src/libslic3r/TriangleMesh.cpp

@@ -215,6 +215,47 @@ TriangleMesh::repair() {
     BOOST_LOG_TRIVIAL(debug) << "TriangleMesh::repair() finished";
 }
 
+
+float TriangleMesh::volume()
+{
+    if (this->stl.stats.volume == -1) 
+        stl_calculate_volume(&this->stl);
+    return this->stl.stats.volume;
+}
+
+void TriangleMesh::check_topology()
+{
+    // checking exact
+    stl_check_facets_exact(&stl);
+    stl.stats.facets_w_1_bad_edge = (stl.stats.connected_facets_2_edge - stl.stats.connected_facets_3_edge);
+    stl.stats.facets_w_2_bad_edge = (stl.stats.connected_facets_1_edge - stl.stats.connected_facets_2_edge);
+    stl.stats.facets_w_3_bad_edge = (stl.stats.number_of_facets - stl.stats.connected_facets_1_edge);
+    
+    // checking nearby
+    //int last_edges_fixed = 0;
+    float tolerance = stl.stats.shortest_edge;
+    float increment = stl.stats.bounding_diameter / 10000.0;
+    int iterations = 2;
+    if (stl.stats.connected_facets_3_edge < stl.stats.number_of_facets) {
+        for (int i = 0; i < iterations; i++) {
+            if (stl.stats.connected_facets_3_edge < stl.stats.number_of_facets) {
+                //printf("Checking nearby. Tolerance= %f Iteration=%d of %d...", tolerance, i + 1, iterations);
+                stl_check_facets_nearby(&stl, tolerance);
+                //printf("  Fixed %d edges.\n", stl.stats.edges_fixed - last_edges_fixed);
+                //last_edges_fixed = stl.stats.edges_fixed;
+                tolerance += increment;
+            } else {
+                break;
+            }
+        }
+    }
+}
+
+bool TriangleMesh::is_manifold() const
+{
+    return this->stl.stats.connected_facets_3_edge == this->stl.stats.number_of_facets;
+}
+
 void
 TriangleMesh::reset_repair_stats() {
     this->stl.stats.degenerate_facets   = 0;

xs/src/libslic3r/TriangleMesh.hpp

@@ -32,6 +32,9 @@ public:
     void write_ascii(const char* output_file);
     void write_binary(const char* output_file);
     void repair();
+    float volume();
+    void check_topology();
+    bool is_manifold() const;
     void WriteOBJFile(char* output_file);
     void scale(float factor);
     void scale(const Pointf3 &versor);

xs/xsp/Model.xsp

@@ -15,6 +15,15 @@
     Model();
     ~Model();
 
+    %name{read_from_file} Model(std::string input_file, bool add_default_instances = true)
+        %code%{
+            try {
+                RETVAL = new Model(Model::read_from_file(input_file, add_default_instances));
+            } catch (std::exception& e) {
+                croak("Error while opening %s: %s\n", input_file.c_str(), e.what());
+            }
+        %};
+
     Clone<Model> clone()
         %code%{ RETVAL = THIS; %};
     
@@ -73,6 +82,11 @@
     void duplicate_objects(unsigned int copies_num, double dist, BoundingBoxf* bb = NULL);
     void duplicate_objects_grid(unsigned int x, unsigned int y, double dist);
 
+    bool looks_like_multipart_object() const;
+    void convert_multipart_object();
+
+    void print_info() const;
+
     bool store_stl(char *path, bool binary)
         %code%{ TriangleMesh mesh = THIS->mesh(); RETVAL = Slic3r::store_stl(path, &mesh, binary); %};
     bool store_amf(char *path)
@@ -272,6 +286,8 @@ ModelMaterial::attributes()
             RETVAL = new ModelObjectPtrs();  // leak?
             THIS->split(RETVAL);
         %};
+
+    void print_info() const;
 };