Lay flat - rotation is now done in one go directly about the necessary axis

lib/Slic3r/GUI/Plater.pm

@@ -140,10 +140,16 @@ sub new {
     };
     
     # callback to react to gizmo rotate
+    # omitting last three parameters means rotation around Z
+    # otherwise they are the components of the rotation axis vector
     my $on_gizmo_rotate = sub {
-        my ($angle_z, $angle_y) = @_;
+        my ($angle, $axis_x, $axis_y, $axis_z) = @_;
-        $self->rotate(rad2deg($angle_z), Z, 'absolute');
+	if (!defined $axis_x) {
-        $self->rotate(rad2deg($angle_y), Y, 'absolute') if $angle_y != 0;
+            $self->rotate(rad2deg($angle), Z, 'absolute');
+        }
+        else {
+            $self->rotate(rad2deg($angle), undef, 'absolute', $axis_x, $axis_y, $axis_z) if $angle != 0;
+        }
     };
 
     # callback to update object's geometry info while using gizmos
@@ -1031,28 +1037,40 @@ sub _get_number_from_user {
 }
 
 sub rotate {
-    my ($self, $angle, $axis, $relative_key) = @_;
+    my ($self, $angle, $axis, $relative_key, $axis_x, $axis_y, $axis_z) = @_;
     $relative_key //= 'absolute'; # relative or absolute coordinates
-    $axis //= Z; # angle is in degrees
+    $axis_x //= 0;
-
+    $axis_y //= 0;
+    $axis_z //= 0;
     my $relative = $relative_key eq 'relative';    
-    
+
     my ($obj_idx, $object) = $self->selected_object;
     return if !defined $obj_idx;
-    
+
     my $model_object = $self->{model}->objects->[$obj_idx];
     my $model_instance = $model_object->instances->[0];
-        
+
     if (!defined $angle) {
         my $axis_name = $axis == X ? 'X' : $axis == Y ? 'Y' : 'Z';
         my $default = $axis == Z ? rad2deg($model_instance->rotation) : 0;
         $angle = $self->_get_number_from_user(L("Enter the rotation angle:"), L("Rotate around ").$axis_name.(" axis"), L("Invalid rotation angle entered"), $default);
         return if $angle eq '';
     }
+
+    # Let's calculate vector of rotation axis (if we don't have it already)
+    # The minus is there so that the direction is the same as was established
+    if (defined $axis) {
+        if ($axis == X) {
+            $axis_x = -1;
+        }
+        if ($axis == Y) {
+            $axis_y = -1;
+        }
+    }
     
     $self->stop_background_process;
     
-    if ($axis == Z) {
+    if (defined $axis && $axis == Z) {
         my $new_angle = deg2rad($angle);
         foreach my $inst (@{ $model_object->instances }) {
             my $rotation = ($relative ? $inst->rotation : 0.) + $new_angle;
@@ -1067,13 +1085,15 @@ sub rotate {
         }
 #        $object->transform_thumbnail($self->{model}, $obj_idx);
     } else {
-        # rotation around X and Y needs to be performed on mesh
+        if (defined $axis) {
-        # so we first apply any Z rotation
+            # rotation around X and Y needs to be performed on mesh
-        if ($model_instance->rotation != 0) {
+            # so we first apply any Z rotation
-            $model_object->rotate($model_instance->rotation, Z);
+            if ($model_instance->rotation != 0) {
-            $_->set_rotation(0) for @{ $model_object->instances };
+                $model_object->rotate($model_instance->rotation, Slic3r::Pointf3->new(0, 0, -1));
+                $_->set_rotation(0) for @{ $model_object->instances };
+            }
         }
-        $model_object->rotate(deg2rad($angle), $axis);
+        $model_object->rotate(deg2rad($angle), Slic3r::Pointf3->new($axis_x, $axis_y, $axis_z));
         
 #        # realign object to Z = 0
 #        $model_object->center_around_origin;
@@ -1099,7 +1119,7 @@ sub mirror {
     
     # apply Z rotation before mirroring
     if ($model_instance->rotation != 0) {
-        $model_object->rotate($model_instance->rotation, Z);
+        $model_object->rotate($model_instance->rotation, Slic3r::Pointf3->new(0, 0, 1));
         $_->set_rotation(0) for @{ $model_object->instances };
     }
     
@@ -1146,7 +1166,7 @@ sub changescale {
         
         # apply Z rotation before scaling
         if ($model_instance->rotation != 0) {
-            $model_object->rotate($model_instance->rotation, Z);
+            $model_object->rotate($model_instance->rotation, Slic3r::Pointf3->new(0, 0, 1));
             $_->set_rotation(0) for @{ $model_object->instances };
         }
         

xs/src/libslic3r/Model.cpp

@@ -725,7 +725,7 @@ void ModelObject::scale(const Pointf3 &versor)
     this->invalidate_bounding_box();
 }
 
-void ModelObject::rotate(float angle, const Axis &axis)
+void ModelObject::rotate(float angle, const Pointf3& axis)
 {
     for (ModelVolume *v : this->volumes)
     {

xs/src/libslic3r/Model.hpp

@@ -120,7 +120,7 @@ public:
     void translate(const Vectorf3 &vector) { this->translate(vector.x, vector.y, vector.z); }
     void translate(coordf_t x, coordf_t y, coordf_t z);
     void scale(const Pointf3 &versor);
-    void rotate(float angle, const Axis &axis);
+    void rotate(float angle, const Pointf3& axis);
     void transform(const float* matrix3x4);
     void mirror(const Axis &axis);
     size_t materials_count() const;

xs/src/libslic3r/TriangleMesh.cpp

@@ -324,6 +324,17 @@ void TriangleMesh::translate(float x, float y, float z)
     stl_invalidate_shared_vertices(&this->stl);
 }
 
+void TriangleMesh::rotate(float angle, Pointf3 axis)
+{
+    if (angle == 0.f)
+        return;
+
+    axis = normalize(axis);
+    Eigen::Transform<float, 3, Eigen::Affine> m = Eigen::Transform<float, 3, Eigen::Affine>::Identity();
+    m.rotate(Eigen::AngleAxisf(angle, Eigen::Vector3f(axis.x, axis.y, axis.z)));
+    stl_transform(&stl, (float*)m.data());
+}
+
 void TriangleMesh::rotate(float angle, const Axis &axis)
 {
     if (angle == 0.f)

xs/src/libslic3r/TriangleMesh.hpp

@@ -40,6 +40,7 @@ public:
     void scale(const Pointf3 &versor);
     void translate(float x, float y, float z);
     void rotate(float angle, const Axis &axis);
+    void rotate(float angle, Pointf3 axis);
     void rotate_x(float angle);
     void rotate_y(float angle);
     void rotate_z(float angle);

xs/src/slic3r/GUI/GLCanvas3D.cpp

@@ -2805,9 +2805,9 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
                 // Rotate the object so the normal points downward:
                 Pointf3 normal = m_gizmos.get_flattening_normal();
                 if (normal.x != 0.f || normal.y != 0.f || normal.z != 0.f) {
-                    float angle_z = -atan2(normal.y, normal.x);
+                    Pointf3 axis = normal.z > 0.999f ? Pointf3(1, 0, 0) : cross(normal, Pointf3(0.f, 0.f, -1.f));
-                    float angle_y = M_PI - atan2(normal.x*cos(angle_z)-normal.y*sin(angle_z), normal.z);
+                    float angle = -acos(-normal.z);
-                    m_on_gizmo_rotate_callback.call((double)angle_z, (double)angle_y);
+                    m_on_gizmo_rotate_callback.call(angle, axis.x, axis.y, axis.z);
                 }
             }
         }
@@ -3093,7 +3093,7 @@ void GLCanvas3D::on_mouse(wxMouseEvent& evt)
             }
             case Gizmos::Rotate:
             {
-                m_on_gizmo_rotate_callback.call((double)m_gizmos.get_angle_z(), 0.);
+                m_on_gizmo_rotate_callback.call((double)m_gizmos.get_angle_z());
                 break;
             }
             default:

xs/src/slic3r/GUI/GLGizmo.cpp

@@ -706,12 +706,14 @@ void GLGizmoFlatten::update_planes()
         }
         polygon = Slic3r::Geometry::convex_hull(polygon); // To remove the inner points
 
-        // Calculate area of the polygon and discard ones that are too small
+        // We will calculate area of the polygon and discard ones that are too small
+        // The limit is more forgiving in case the normal is in the direction of the coordinate axes
+        const float minimal_area = (std::abs(normal.x) > 0.999f || std::abs(normal.y) > 0.999f || std::abs(normal.z) > 0.999f) ? 1.f : 20.f;
         float area = 0.f;
         for (unsigned int i = 0; i < polygon.size(); i++) // Shoelace formula
             area += polygon[i].x*polygon[i+1 < polygon.size() ? i+1 : 0 ].y - polygon[i+1 < polygon.size() ? i+1 : 0].x*polygon[i].y;
         area = std::abs(area/2.f);
-        if (area < 20.f) {
+        if (area < minimal_area) {
             m_planes.erase(m_planes.begin()+(polygon_id--));
             continue;
         }

xs/xsp/Model.xsp

@@ -301,7 +301,8 @@ ModelMaterial::attributes()
     void translate(double x, double y, double z);
     void scale_xyz(Pointf3* versor)
         %code{% THIS->scale(*versor); %};
-    void rotate(float angle, Axis axis);
+    void rotate(float angle, Pointf3* axis)
+        %code{% THIS->rotate(angle, *axis); %};
     void mirror(Axis axis);
     
     Model* cut(double z)