Fixed crash with zero support base spacing.

Zero support base spacing is newly allowed, switching from
the "support base" infill pattern to rectilinar infill pattern.
Why someone would want to use a solid infill for support base eludes me,
but it is simpler to support it instead of working out some rules on
minimum support base density.

Fixes Support patern spacing set to zero causing crash #6989

1 files changed, 5 insertions, 6 deletions

diff --git a/src/libslic3r/SupportMaterial.cpp b/src/libslic3r/SupportMaterial.cpp
index f727d334d..2bcf99c57 100644
--- a/src/libslic3r/SupportMaterial.cpp
+++ b/src/libslic3r/SupportMaterial.cpp
@@ -721,9 +721,9 @@ public:
     #ifdef SUPPORT_USE_AGG_RASTERIZER
             m_bbox       = bbox;
             // Oversample the grid to avoid leaking of supports through or around the object walls.
-            int oversampling = std::min(8, int(scale_(m_support_spacing) / (scale_(params.extrusion_width) + 100)));
-            m_pixel_size = scale_(m_support_spacing / oversampling);
-            assert(scale_(params.extrusion_width) + 20 < m_pixel_size);
+            int extrusion_width_scaled = scale_(params.extrusion_width);
+            int oversampling = std::clamp(int(scale_(m_support_spacing) / (extrusion_width_scaled + 100)), 1, 8);
+            m_pixel_size = std::max<double>(extrusion_width_scaled + 21, scale_(m_support_spacing / oversampling));
             // Add one empty column / row boundaries.
             m_bbox.offset(m_pixel_size);
             // Grid size fitting the support polygons plus one pixel boundary around the polygons.
@@ -2600,8 +2600,6 @@ void PrintObjectSupportMaterial::generate_base_layers(
         // No top contacts -> no intermediate layers will be produced.
         return;
 
-    // coordf_t fillet_radius_scaled = scale_(m_object_config->support_material_spacing);
-
     BOOST_LOG_TRIVIAL(debug) << "PrintObjectSupportMaterial::generate_base_layers() in parallel - start";
     tbb::parallel_for(
         tbb::blocked_range<size_t>(0, intermediate_layers.size()),
@@ -2696,6 +2694,7 @@ void PrintObjectSupportMaterial::generate_base_layers(
                 layer_intermediate.layer_type = sltBase;
 
         #if 0
+                    // coordf_t fillet_radius_scaled = scale_(m_object_config->support_material_spacing);
                     // Fillet the base polygons and trim them again with the top, interface and contact layers.
                     $base->{$i} = diff(
                         offset2(
@@ -3784,7 +3783,7 @@ void PrintObjectSupportMaterial::generate_toolpaths(
     // Prepare fillers.
     SupportMaterialPattern  support_pattern = m_object_config->support_material_pattern;
     bool                    with_sheath     = m_object_config->support_material_with_sheath;
-    InfillPattern           infill_pattern = (support_pattern == smpHoneycomb ? ipHoneycomb : ipSupportBase);
+    InfillPattern           infill_pattern = support_pattern == smpHoneycomb ? ipHoneycomb : (support_density < 1.05 ? ipRectilinear : ipSupportBase);
     std::vector<float>      angles;
     angles.push_back(base_angle);