Layer subdivision fix

src/libslic3r/GCode.cpp

@@ -6101,7 +6101,17 @@ LayerResult GCode::process_layer(
         const bool island_level_ordering = print.config().print_sequence != PrintSequence::ByObject &&
             single_object_instance_idx == size_t(-1) &&
             print.config().print_order != PrintOrder::AsObjectList;
-        for (unsigned int filament_id : layer_tools.extruders) {
+        // A mixed-color slot is absent from layer_tools.extruders by design: resolve_mixed_filaments()
+        // replaced it with its physical components. Its geometry is still keyed under the slot in
+        // by_extruder though, and the sublayer emitter looks the plan up by slot id, so append the
+        // slots here. Appended (not merged) so the existing order is untouched, and empty for every
+        // configuration without sublayer splitting.
+        std::vector<unsigned int> plan_filaments = layer_tools.extruders;
+        for (const auto &grp : layer_tools.mixed_sub_layer_groups)
+            if (std::find(plan_filaments.begin(), plan_filaments.end(), grp.mixed_slot_0based) == plan_filaments.end())
+                plan_filaments.push_back(grp.mixed_slot_0based);
+
+        for (unsigned int filament_id : plan_filaments) {
             auto objects_by_extruder_it = by_extruder.find(filament_id);
             if (objects_by_extruder_it == by_extruder.end()) continue;
 
@@ -6282,8 +6292,22 @@ LayerResult GCode::process_layer(
         }
 
         if (print.config().print_sequence == PrintSequence::ByLayer && m_enable_exclude_object && print.config().support_object_skip_flush.value) {
-            std::vector<size_t> filament_instances_id;
-            for (InstanceToPrint &instance : filament_to_print_instances[extruder_id].first) filament_instances_id.emplace_back(instance.label_object_id);
+            std::set<size_t> all_label_ids;
+            for (InstanceToPrint &instance : filament_to_print_instances[extruder_id].first)
+                all_label_ids.insert(instance.label_object_id);
+            // This extruder may also be printing sub-layers on behalf of a mixed slot, whose
+            // instances live under the slot id. Their labels belong in the same skip set, or
+            // exclude-object would not skip that geometry.
+            for (const auto &grp : layer_tools.mixed_sub_layer_groups)
+                for (unsigned int comp : grp.components_0based)
+                    if (comp == extruder_id) {
+                        auto mit = filament_to_print_instances.find(grp.mixed_slot_0based);
+                        if (mit != filament_to_print_instances.end())
+                            for (const InstanceToPrint &inst : mit->second.first)
+                                all_label_ids.insert(inst.label_object_id);
+                        break;
+                    }
+            std::vector<size_t> filament_instances_id(all_label_ids.begin(), all_label_ids.end());
             m_filament_instances_code = _encode_label_ids_to_base64(filament_instances_id);
         }
 

tests/fff_print/CMakeLists.txt

@@ -15,6 +15,7 @@ add_executable(${_TEST_NAME}_tests
 	test_perimeters.cpp
 	test_print.cpp
 	test_printobject.cpp
+	test_mixed_filament.cpp
 	test_skirt_brim.cpp
 	test_slicing_pipeline_hook.cpp
 	test_support_material.cpp

tests/fff_print/test_mixed_filament.cpp

@@ -0,0 +1,137 @@
+#include <catch2/catch_all.hpp>
+
+#include "libslic3r/GCode/ToolOrdering.hpp"
+#include "libslic3r/Print.hpp"
+
+#include "test_helpers.hpp"
+
+using namespace Slic3r;
+using namespace Slic3r::Test;
+
+namespace {
+
+// Two physical filaments plus one mixed slot (config index 2, 1-based id 3) blending them 60/40.
+// The mixed arrays are parallel to filament_colour and must be sized to the filament count.
+// Note ConfigOptionBools deserializes on ',' while ConfigOptionStrings uses ';'.
+DynamicPrintConfig mixed_config(bool sublayer_on, const char *ratios = "0.6,0.4")
+{
+    DynamicPrintConfig config = multifilament_config(3);
+    config.set_deserialize_strict({
+        {"filament_is_mixed",               "0,0,1"},
+        {"filament_mixed_components",       ";;1,2"},
+        {"filament_mixed_sublayer_ratios",  std::string(";;") + ratios},
+        {"filament_mixed_gradient",         "0,0,0"},
+        {"filament_mixed_gradient_range",   ";;"},
+        {"filament_mixed_gradient_curve",   ";;"},
+        {"filament_mixed_gradient_per_part","0,0,0"},
+        {"enable_mixed_color_sublayer",     sublayer_on ? "1" : "0"},
+        // Assign every region role to the mixed slot so it actually participates in slicing.
+        {"outer_wall_filament_id",          "3"},
+        {"inner_wall_filament_id",          "3"},
+        {"sparse_infill_filament_id",       "3"},
+        {"internal_solid_filament_id",      "3"},
+        {"top_surface_filament_id",         "3"},
+        {"bottom_surface_filament_id",      "3"},
+    });
+    return config;
+}
+
+// Total sub-layer groups and per-layer DRR resolutions across the whole tool ordering.
+void count_mixed(ToolOrdering &to, size_t &groups, size_t &resolutions)
+{
+    groups = resolutions = 0;
+    for (const LayerTools &lt : to.layer_tools()) {
+        groups      += lt.mixed_sub_layer_groups.size();
+        resolutions += lt.mixed_filament_resolution.size();
+    }
+}
+
+} // namespace
+
+TEST_CASE("enable_mixed_color_sublayer reaches the Print config", "[MixedFilament]")
+{
+    Print print;
+    Model model;
+    init_print({cube(20)}, print, model, mixed_config(true));
+
+    // The option lives in PrintConfig; if it did not survive Print::apply the slicer would
+    // silently fall back to the whole-layer path.
+    CHECK(print.config().enable_mixed_color_sublayer.value == true);
+    REQUIRE(print.config().filament_is_mixed.values.size() == 3);
+    CHECK(print.config().filament_is_mixed.values[2] == true);
+    REQUIRE(print.config().filament_mixed_components.values.size() == 3);
+    CHECK(print.config().filament_mixed_components.values[2] == "1,2");
+}
+
+TEST_CASE("Mixed filament splits layers into sub-layers when the option is on", "[MixedFilament]")
+{
+    Print print;
+    Model model;
+    init_print({cube(20)}, print, model, mixed_config(true));
+    print.process();
+
+    ToolOrdering &to = const_cast<ToolOrdering &>(print.tool_ordering());
+    REQUIRE(!to.layer_tools().empty());
+
+    size_t groups = 0, resolutions = 0;
+    count_mixed(to, groups, resolutions);
+
+    INFO("layers=" << to.layer_tools().size() << " groups=" << groups);
+    CHECK(groups > 0);
+}
+
+TEST_CASE("Mixed filament alternates whole layers when the option is off", "[MixedFilament]")
+{
+    Print print;
+    Model model;
+    init_print({cube(20)}, print, model, mixed_config(false));
+    print.process();
+
+    ToolOrdering &to = const_cast<ToolOrdering &>(print.tool_ordering());
+    REQUIRE(!to.layer_tools().empty());
+
+    size_t groups = 0, resolutions = 0;
+    count_mixed(to, groups, resolutions);
+
+    // With splitting off the slot is realized by the deficit round-robin scheduler instead:
+    // no sub-layer groups, but a per-layer resolution to one physical component.
+    INFO("layers=" << to.layer_tools().size() << " resolutions=" << resolutions);
+    CHECK(groups == 0);
+    CHECK(resolutions > 0);
+}
+
+TEST_CASE("Sub-layer splitting emits the scaled sub-heights into G-code", "[MixedFilament]")
+{
+    // layer_height 0.2 split 60/40 gives sub-layers of 0.12 and 0.08. The emitter reports the
+    // sub-height (not the nominal layer height) in the HEIGHT tag and scales flow to match.
+    DynamicPrintConfig config = mixed_config(true);
+    config.set_deserialize_strict({{"layer_height", "0.2"}, {"initial_layer_print_height", "0.2"}});
+
+    Print print;
+    Model model;
+    init_print({cube(20)}, print, model, config);
+    print.process();
+    const std::string gc = Slic3r::Test::gcode(print);
+
+    REQUIRE(!gc.empty());
+    INFO("gcode bytes=" << gc.size());
+    CHECK(gc.find(";HEIGHT:0.12") != std::string::npos);
+    CHECK(gc.find(";HEIGHT:0.08") != std::string::npos);
+}
+
+TEST_CASE("Whole-layer mixing emits only the nominal layer height", "[MixedFilament]")
+{
+    DynamicPrintConfig config = mixed_config(false);
+    config.set_deserialize_strict({{"layer_height", "0.2"}, {"initial_layer_print_height", "0.2"}});
+
+    Print print;
+    Model model;
+    init_print({cube(20)}, print, model, config);
+    print.process();
+    const std::string gc = Slic3r::Test::gcode(print);
+
+    REQUIRE(!gc.empty());
+    // No sub-layer split, so the 60/40 sub-heights must never appear.
+    CHECK(gc.find(";HEIGHT:0.12") == std::string::npos);
+    CHECK(gc.find(";HEIGHT:0.08") == std::string::npos);
+}