Curve: reduce overhead in debug builds

source/blender/blenkernel/BKE_curves.hh

@@ -117,6 +117,14 @@ class CurvesGeometryRuntime {
 
   /** Stores weak references to material data blocks. */
   std::unique_ptr<bake::BakeMaterialsList> bake_materials;
+
+  /**
+   * Type counts have to be set eagerly after each operation. It's checked with asserts that the
+   * type counts are correct when accessed. However, this check is expensive and shouldn't be done
+   * all the time because it makes debug builds unusable in some situations that would be fine
+   * otherwise.
+   */
+  bool check_type_counts = true;
 };
 
 /**
@@ -894,13 +902,22 @@ inline bool CurvesGeometry::has_curve_with_type(const Span<CurveType> types) con
 
 inline const std::array<int, CURVE_TYPES_NUM> &CurvesGeometry::curve_type_counts() const
 {
-  BLI_assert(this->runtime->type_counts == calculate_type_counts(this->curve_types()));
+#ifndef NDEBUG
+
+  if (this->runtime->check_type_counts) {
+    const std::array<int, CURVE_TYPES_NUM> actual_type_counts = calculate_type_counts(
+        this->curve_types());
+    BLI_assert(this->runtime->type_counts == actual_type_counts);
+    this->runtime->check_type_counts = false;
+  }
+#endif
   return this->runtime->type_counts;
 }
 
 inline OffsetIndices<int> CurvesGeometry::points_by_curve() const
 {
-  return OffsetIndices<int>({this->curve_offsets, this->curve_num + 1});
+  return OffsetIndices<int>({this->curve_offsets, this->curve_num + 1},
+                            offset_indices::NoSortCheck{});
 }
 
 inline int CurvesGeometry::evaluated_points_num() const

source/blender/blenkernel/intern/curves_geometry.cc

@@ -116,7 +116,8 @@ CurvesGeometry::CurvesGeometry(const CurvesGeometry &other)
                             other.runtime->evaluated_length_cache,
                             other.runtime->evaluated_tangent_cache,
                             other.runtime->evaluated_normal_cache,
-                            {}});
+                            {},
+                            true});
 
   if (other.runtime->bake_materials) {
     this->runtime->bake_materials = std::make_unique<bake::BakeMaterialsList>(
@@ -1065,6 +1066,7 @@ void CurvesGeometry::tag_topology_changed()
   this->tag_positions_changed();
   this->runtime->evaluated_offsets_cache.tag_dirty();
   this->runtime->nurbs_basis_cache.tag_dirty();
+  this->runtime->check_type_counts = true;
 }
 void CurvesGeometry::tag_normals_changed()
 {

source/blender/blenlib/BLI_offset_indices.hh

@@ -12,6 +12,9 @@
 
 namespace blender::offset_indices {
 
+/** Utility struct that can be passed into a function to skip a check for sorted indices. */
+struct NoSortCheck {};
+
 /**
  * References an array of ascending indices. A pair of consecutive indices encode an index range.
  * Another common way to store the same kind of data is to store the start and size of every range
@@ -35,6 +38,13 @@ template<typename T> class OffsetIndices {
     BLI_assert(offsets_.size() < 2 || std::is_sorted(offsets_.begin(), offsets_.end()));
   }
 
+  /**
+   * Same as above, but skips the debug check that indices are sorted, because that can have a
+   * high performance impact making debug builds unusable for files that would be fine otherwise.
+   * This can be used when it is known that the indices are sorted already.
+   */
+  OffsetIndices(const Span<T> offsets, NoSortCheck) : offsets_(offsets) {}
+
   /** Return the total number of elements in the referenced arrays. */
   T total_size() const
   {