Create method for infill above bridges identification

src/libslic3r/CMakeLists.txt

@@ -245,6 +245,8 @@ set(SLIC3R_SOURCES
     Geometry/VoronoiUtils.hpp
     Geometry/VoronoiUtils.cpp
     Geometry/VoronoiVisualUtils.hpp
+    InfillAboveBridges.hpp
+    InfillAboveBridges.cpp
     JumpPointSearch.cpp
     JumpPointSearch.hpp
     KDTreeIndirect.hpp

src/libslic3r/ExtrusionRole.hpp

@@ -31,6 +31,7 @@ enum class ExtrusionRoleModifier : uint16_t {
     Solid,
     Ironing,
     Bridge,
+    OverBridge,
 // 3) Special types
     // Indicator that the extrusion role was mixed from multiple differing extrusion roles,
     // for example from Support and SupportInterface.
@@ -62,6 +63,7 @@ struct ExtrusionRole : public ExtrusionRoleModifiers
     static constexpr const ExtrusionRoleModifiers SolidInfill{ ExtrusionRoleModifier::Infill | ExtrusionRoleModifier::Solid };
     // Top solid infill (visible).
     //FIXME why there is no bottom solid infill type?
+    static constexpr const ExtrusionRoleModifiers InfillOverBridge{ ExtrusionRoleModifier::Infill | ExtrusionRoleModifier::Solid | ExtrusionRoleModifier::OverBridge };
     static constexpr const ExtrusionRoleModifiers TopSolidInfill{ ExtrusionRoleModifier::Infill | ExtrusionRoleModifier::Solid | ExtrusionRoleModifier::External };
     // Ironing infill at the top surfaces.
     static constexpr const ExtrusionRoleModifiers Ironing{ ExtrusionRoleModifier::Infill | ExtrusionRoleModifier::Solid | ExtrusionRoleModifier::Ironing | ExtrusionRoleModifier::External };

src/libslic3r/Fill/Fill.cpp

@@ -183,15 +183,24 @@ std::vector<SurfaceFill> group_fills(const Layer &layer)
 		        } else if (params.density <= 0)
 		            continue;
 
-		        params.extrusion_role =
+		        if (is_bridge) {
-		            is_bridge ?
+		            params.extrusion_role = ExtrusionRole::BridgeInfill;
-		                ExtrusionRole::BridgeInfill :
+                } else {
-		                (surface.is_solid() ?
+                    if (surface.is_solid()) {
-		                    (surface.is_top() ? ExtrusionRole::TopSolidInfill : ExtrusionRole::SolidInfill) :
+                        if (surface.is_top()) {
-							ExtrusionRole::InternalInfill);
+                            params.extrusion_role = ExtrusionRole::TopSolidInfill;
+                        } else if (surface.surface_type == stSolidOverBridge) {
+                            params.extrusion_role = ExtrusionRole::InfillOverBridge;
+                        } else {
+                            params.extrusion_role = ExtrusionRole::SolidInfill;
+                        }
+                    } else {
+                        params.extrusion_role = ExtrusionRole::InternalInfill;
+                    }
+                }
 		        params.bridge_angle = float(surface.bridge_angle);
 		        params.angle 		= float(Geometry::deg2rad(region_config.fill_angle.value));
-		        
+
 		        // Calculate the actual flow we'll be using for this infill.
 		        params.bridge = is_bridge || Fill::use_bridge_flow(params.pattern);
 				params.flow   = params.bridge ?
@@ -342,7 +351,9 @@ std::vector<SurfaceFill> group_fills(const Layer &layer)
     // Use ipEnsuring pattern for all internal Solids.
     {
         for (size_t surface_fill_id = 0; surface_fill_id < surface_fills.size(); ++surface_fill_id)
-            if (SurfaceFill &fill = surface_fills[surface_fill_id]; fill.surface.surface_type == stInternalSolid) {
+            if (SurfaceFill &fill = surface_fills[surface_fill_id];
+                    fill.surface.surface_type == stInternalSolid
+                    || fill.surface.surface_type == stSolidOverBridge) {
                 fill.params.pattern = ipEnsuring;
             }
     }

src/libslic3r/GCode.cpp

@@ -3387,6 +3387,8 @@ std::string GCodeGenerator::_extrude(
             speed = m_config.get_abs_value("infill_speed");
         } else if (path_attr.role == ExtrusionRole::SolidInfill) {
             speed = m_config.get_abs_value("solid_infill_speed");
+        } else if (path_attr.role == ExtrusionRole::InfillOverBridge) {
+            speed = 10;
         } else if (path_attr.role == ExtrusionRole::TopSolidInfill) {
             speed = m_config.get_abs_value("top_solid_infill_speed");
         } else if (path_attr.role == ExtrusionRole::Ironing) {

src/libslic3r/InfillAboveBridges.cpp

@@ -0,0 +1,36 @@
+#include <tcbspan/span.hpp>
+#include "libslic3r/InfillAboveBridges.hpp"
+#include "libslic3r/ClipperUtils.hpp"
+
+namespace Slic3r::PrepareInfill {
+    void mark_as_infill_above_bridge(const ExPolygons &marker, const SurfaceRefsByRegion &layer) {
+        for (const SurfaceCollectionRef &region : layer) {
+            const ExPolygons intersection{intersection_ex(region.get().filter_by_type(stInternalSolid), marker, ApplySafetyOffset::No)};
+            if (intersection.empty()) {
+                continue;
+            }
+            const ExPolygons clipped{diff_ex(region.get().filter_by_type(stInternalSolid), marker, ApplySafetyOffset::Yes)};
+            region.get().remove_type(stInternalSolid);
+            region.get().append(clipped, stInternalSolid);
+            region.get().append(intersection, stSolidOverBridge);
+        }
+    }
+
+    void separate_infill_above_bridges(const SurfaceRefs &surfaces) {
+        if (surfaces.empty()) {
+            return;
+        }
+
+        const SurfaceRefsByRegion *previous_layer{&surfaces.front()};
+        for (const SurfaceRefsByRegion &layer : tcb::span{surfaces}.subspan(1)) {
+            ExPolygons bridges;
+            for (const SurfaceCollectionRef &region : *previous_layer) {
+                for (const Surface *bridge : region.get().filter_by_type(stBottomBridge)) {
+                    bridges.push_back(bridge->expolygon);
+                }
+            }
+            mark_as_infill_above_bridge(bridges, layer);
+            previous_layer = &layer;
+        }
+    }
+}

src/libslic3r/InfillAboveBridges.hpp

@@ -0,0 +1,16 @@
+#ifndef slic3r_InfillAboveBridges_hpp_
+#define slic3r_InfillAboveBridges_hpp_
+
+#include <iostream>
+#include <vector>
+#include "libslic3r/SurfaceCollection.hpp"
+
+namespace Slic3r::PrepareInfill {
+    using SurfaceCollectionRef = std::reference_wrapper<SurfaceCollection>;
+    using SurfaceRefsByRegion = std::vector<SurfaceCollectionRef>;
+    using SurfaceRefs = std::vector<SurfaceRefsByRegion>;
+
+    void separate_infill_above_bridges(const SurfaceRefs &surfaces);
+}
+
+#endif // slic3r_InfillAboveBridges_hpp_

src/libslic3r/PrintObject.cpp

@@ -64,6 +64,7 @@
 #include "libslic3r/TriangleSelector.hpp"
 #include "tcbspan/span.hpp"
 #include "libslic3r/Point.hpp"
+#include "libslic3r/InfillAboveBridges.hpp"
 
 using namespace std::literals;
 
@@ -412,6 +413,19 @@ void PrintObject::prepare_infill()
     } // for each layer
 #endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
 
+
+    PrepareInfill::SurfaceRefs surfaces;
+    for (const Layer *layer : m_layers) {
+        surfaces.emplace_back();
+        for (size_t region_id = 0; region_id < this->num_printing_regions(); ++ region_id) {
+            LayerRegion *layerm = layer->m_regions[region_id];
+            if (!layerm->fill_surfaces().empty()) {
+                surfaces.back().push_back(std::ref(layerm->m_fill_surfaces));
+            }
+        }
+    }
+    PrepareInfill::separate_infill_above_bridges(surfaces);
+
     this->set_done(posPrepareInfill);
 }
 

src/libslic3r/Surface.cpp

@@ -53,6 +53,7 @@ const char* surface_type_to_color_name(const SurfaceType surface_type)
         case stInternalSolid:   return "rgb(255,0,255)"; // magenta
         case stInternalBridge:  return "rgb(0,255,255)";
         case stInternalVoid:    return "rgb(128,128,128)";
+        case stSolidOverBridge: return "rgb(255,128,0)"; // orange
         case stPerimeter:       return "rgb(128,0,0)"; // maroon
         default:                return "rgb(64,64,64)";
     };
@@ -89,6 +90,8 @@ void export_surface_type_legend_to_svg(SVG &svg, const Point &pos)
     svg.draw_legend(Point(pos_x, pos_y), "internal bridge", surface_type_to_color_name(stInternalBridge));
     pos_x += step_x;
     svg.draw_legend(Point(pos_x, pos_y), "internal void"  , surface_type_to_color_name(stInternalVoid));
+    pos_x += step_x;
+    svg.draw_legend(Point(pos_x, pos_y), "over bridge"    , surface_type_to_color_name(stSolidOverBridge));
 }
 
 bool export_to_svg(const char *path, const Surfaces &surfaces, const float transparency)

src/libslic3r/Surface.hpp

@@ -44,6 +44,8 @@ enum SurfaceType {
     stInternalVoid,
     // Inner/outer perimeters.
     stPerimeter,
+    // InternalSolid that is directly above stBottomBridge.
+    stSolidOverBridge,
     // Number of SurfaceType enums.
     stCount,
 };
@@ -111,7 +113,12 @@ public:
 	bool   is_bridge()   const { return this->surface_type == stBottomBridge || this->surface_type == stInternalBridge; }
 	bool   is_external() const { return this->is_top() || this->is_bottom(); }
 	bool   is_internal() const { return ! this->is_external(); }
-	bool   is_solid()    const { return this->is_external() || this->surface_type == stInternalSolid || this->surface_type == stInternalBridge; }
+	bool   is_solid()    const {
+        return this->is_external()
+            || this->surface_type == stInternalSolid
+            || this->surface_type == stSolidOverBridge
+            || this->surface_type == stInternalBridge;
+    }
 };
 
 typedef std::vector<Surface> Surfaces;

tests/fff_print/CMakeLists.txt

@@ -14,6 +14,7 @@ add_executable(${_TEST_NAME}_tests
 	test_gaps.cpp
 	test_gcode.cpp
 	test_gcode_travels.cpp
+    test_infill_above_bridges.cpp
     test_seam_perimeters.cpp
     test_seam_shells.cpp
     test_seam_geometry.cpp

tests/fff_print/test_infill_above_bridges.cpp

@@ -0,0 +1,81 @@
+#include <catch2/catch.hpp>
+#include <libslic3r/InfillAboveBridges.hpp>
+
+using namespace Slic3r;
+
+const ExPolygon square{
+    Point::new_scale(0, 0),
+    Point::new_scale(10, 0),
+    Point::new_scale(10, 10),
+    Point::new_scale(0, 10)
+};
+
+ExPolygon translate(const ExPolygon &polygon, const Point &offset) {
+    ExPolygons result{polygon};
+    translate(result, offset);
+    return result.front();
+}
+
+constexpr bool debug_files{false};
+
+void draw_surfaces(const PrepareInfill::SurfaceRefsByRegion &surfaces, std::string_view file_name) {
+    using PrepareInfill::SurfaceCollectionRef;
+
+    SurfaceCollection to_display;
+    for (const SurfaceCollectionRef &surface_collection : surfaces) {
+        to_display.append(surface_collection.get());
+    }
+    to_display.export_to_svg(file_name.data(), false);
+}
+
+TEST_CASE("Separate infill above bridges", "[PrepareInfill]") {
+    ExPolygons layer_0_region_0_bridge{
+        square
+    };
+    ExPolygons layer_0_region_0_internal{
+        translate(square, Point::new_scale(10, 0))
+    };
+    ExPolygons layer_0_region_1_internal{
+        translate(square, Point::new_scale(0, 10))
+    };
+    ExPolygons layer_0_region_1_bridge{
+        translate(square, Point::new_scale(10, 10))
+    };
+    SurfaceCollection layer_0_region_0;
+    layer_0_region_0.append(layer_0_region_0_bridge, stBottomBridge);
+    layer_0_region_0.append(layer_0_region_0_internal, stInternal);
+    SurfaceCollection layer_0_region_1;
+    layer_0_region_1.append(layer_0_region_1_bridge, stBottomBridge);
+    layer_0_region_1.append(layer_0_region_1_internal, stInternal);
+
+    PrepareInfill::SurfaceRefsByRegion layer_0{layer_0_region_0, layer_0_region_1};
+
+    ExPolygons layer_1_region_0_solid{
+        translate(square, Point::new_scale(5, 5))
+    };
+    SurfaceCollection layer_1_region_0;
+    layer_1_region_0.append(layer_1_region_0_solid, stInternalSolid);
+    PrepareInfill::SurfaceRefsByRegion layer_1{layer_1_region_0};
+
+    if constexpr (debug_files) {
+        draw_surfaces(layer_0, "layer_0.svg");
+    }
+
+    PrepareInfill::separate_infill_above_bridges({layer_0, layer_1});
+
+    if constexpr (debug_files) {
+        draw_surfaces(layer_1, "layer_1.svg");
+    }
+
+    const Surfaces &result{layer_1.front().get().surfaces};
+    REQUIRE(result.size() == 4);
+    const double expected_area{scale_(5.0) * scale_(5.0)};
+    CHECK(result[0].expolygon.contour.area() == Approx(expected_area));
+    CHECK(result[0].surface_type == stInternalSolid);
+    CHECK(result[1].expolygon.contour.area() == Approx(expected_area));
+    CHECK(result[1].surface_type == stInternalSolid);
+    CHECK(result[2].expolygon.contour.area() == Approx(expected_area));
+    CHECK(result[2].surface_type == stSolidOverBridge);
+    CHECK(result[3].expolygon.contour.area() == Approx(expected_area));
+    CHECK(result[3].surface_type == stSolidOverBridge);
+}