Copilot review fixes & upstream code interaction fix (#34)

* first pass at review issue 8
* delete detritus
* fix build compile error due to upstream changes

result.json

@@ -1,7 +0,0 @@
-{
-    "error_string": "Success.",
-    "export_time": 0,
-    "plate_index": 0,
-    "prepare_time": 0,
-    "return_code": 0
-}

src/libslic3r/Print.hpp

@@ -589,6 +589,14 @@ private:
     double                                  m_belt_min_z { 0.0 };
     // Belt printer: XY correction from global pre-slice mode, applied to G-code origin.
     Vec2d                                   m_belt_global_xy_correction { Vec2d::Zero() };
+    // Belt printer: exact belt_floor_z_shift computed during posSlice from a
+    // vertex-level scan of the post-transform mesh.  Cached separately from
+    // m_slicing_params so that rebuilding m_slicing_params on a non-belt-affecting
+    // invalidation (e.g. support config change) doesn't replace the exact value
+    // with the bbox approximation seeded by create_from_config().  Cleared when
+    // posSlice is invalidated.
+    double                                  m_belt_floor_z_shift_cached { 0.0 };
+    bool                                    m_belt_floor_z_shift_cache_valid { false };
 public:
     double belt_global_z_offset() const { return m_belt_global_z_offset; }
     double belt_min_z() const { return m_belt_min_z; }

src/libslic3r/PrintObject.cpp

@@ -1461,15 +1461,16 @@ bool PrintObject::invalidate_step(PrintObjectStep step)
 		invalidated |= this->invalidate_steps({ posPerimeters, posPrepareInfill, posInfill, posIroning, posContouring, posSupportMaterial, posSimplifyPath, posSimplifyInfill });
         invalidated |= m_print->invalidate_steps({ psSkirtBrim });
         m_slicing_params.valid = false;
+        // The exact belt_floor_z_shift is recomputed when slice() runs again.
+        m_belt_floor_z_shift_cache_valid = false;
     } else if (step == posSupportMaterial) {
         invalidated |= this->invalidate_steps({ posSimplifySupportPath });
         invalidated |= m_print->invalidate_steps({ psSkirtBrim });
-        // NOTE: do NOT set m_slicing_params.valid = false here.
-        // belt_floor_z_shift is patched to an exact value during posSlice
-        // (PrintObjectSlice.cpp, after slice_volumes).  Invalidating slicing
-        // params here causes update_slicing_parameters() to overwrite that
-        // exact value with a bounding-box approximation, while posSlice does
-        // not re-run to correct it — breaking belt support clipping.
+        // SlicingParameters depend on support config (enable_support /
+        // raft_layers / enforce_support_layers feed min/max layer height in
+        // Slicing.cpp), so invalidate them here.  The vertex-scan
+        // belt_floor_z_shift is preserved via m_belt_floor_z_shift_cached.
+        m_slicing_params.valid = false;
     }
 
     // Wipe tower depends on the ordering of extruders, which in turn depends on everything.
@@ -1487,6 +1488,7 @@ bool PrintObject::invalidate_all_steps()
     bool result = Inherited::invalidate_all_steps() | m_print->invalidate_all_steps();
 	// Then reset some of the depending values.
 	m_slicing_params.valid = false;
+	m_belt_floor_z_shift_cache_valid = false;
 	return result;
 }
 
@@ -3654,6 +3656,11 @@ void PrintObject::update_slicing_parameters()
           m_slicing_params.belt_floor_shear_factor = belt_floor.shear_factor;
           m_slicing_params.belt_floor_from_axis    = belt_floor.from_axis;
           m_slicing_params.belt_floor_z_shift     = belt_floor.z_shift;
+          // Prefer the vertex-scan z_shift over the bbox approximation when
+          // slice() has already produced one (e.g. this rebuild was triggered
+          // by a support-config change, which doesn't move the belt floor).
+          if (m_belt_floor_z_shift_cache_valid)
+              m_slicing_params.belt_floor_z_shift = m_belt_floor_z_shift_cached;
       }
 }
 

src/libslic3r/PrintObjectSlice.cpp

@@ -1164,6 +1164,13 @@ void PrintObject::slice()
                     << " center_offset=(" << unscale<double>(m_center_offset.x())
                     << ", " << unscale<double>(m_center_offset.y()) << ")";
             }
+
+            // Cache the final patched belt_floor_z_shift so a later support-only
+            // invalidation can rebuild m_slicing_params without losing this exact
+            // (vertex-scan-derived) value.  update_slicing_parameters() will
+            // restore it after create_from_config() seeds the bbox approximation.
+            m_belt_floor_z_shift_cached      = m_slicing_params.belt_floor_z_shift;
+            m_belt_floor_z_shift_cache_valid = true;
         }
     }
 

src/slic3r/GUI/3DScene.cpp

@@ -1117,10 +1117,7 @@ void GLVolumeCollection::render(GLVolumeCollection::ERenderType       type,
             shader->set_uniform("print_volume.type", -1);
         }
         
-        bool  enable_support;
-        int   support_threshold_angle = get_selection_support_threshold_angle(enable_support);
-
-        float normal_z  = -::cos(Geometry::deg2rad((float) support_threshold_angle));
+        const float normal_z = get_selection_support_normal_z();
 
         // Compute up direction accounting for build plate tilt
         Vec3f up_direction = Vec3f::UnitZ();