Curves: Remove redundant custom data pointers

These mutable pointers present problems with ownership in relation to
proper copy-on-write for attributes. The simplest solution is to just
remove them and retrieve the layers from  `CustomData` when they are
needed. This also removes the complexity and redundancy of having to
update the pointers as the curves change. A similar change will apply
to meshes and point clouds.

One downside of this change is that it makes random access with RNA
slower. However, it's simple to just use the RNA attribute API instead,
which is unaffected. In this patch I updated Cycles to do that. With
the future attribute CoW changes, this generic approach makes sense
because Cycles can just request ownership of the existing arrays.

Differential Revision: https://developer.blender.org/D15486

1 files changed, 7 insertions, 27 deletions

diff --git a/source/blender/blenkernel/intern/curves_geometry.cc b/source/blender/blenkernel/intern/curves_geometry.cc
index 8d955a46275..7fc660cfbfc 100644
--- a/source/blender/blenkernel/intern/curves_geometry.cc
+++ b/source/blender/blenkernel/intern/curves_geometry.cc
@@ -68,8 +68,6 @@ CurvesGeometry::CurvesGeometry(const int point_num, const int curve_num)
 #endif
   this->offsets_for_write().first() = 0;
 
-  this->update_customdata_pointers();
-
   this->runtime = MEM_new<CurvesGeometryRuntime>(__func__);
   /* Fill the type counts with the default so they're in a valid state. */
   this->runtime->type_counts[CURVE_TYPE_CATMULL_ROM] = curve_num;
@@ -95,8 +93,6 @@ static void copy_curves_geometry(CurvesGeometry &dst, const CurvesGeometry &src)
 
   /* Though type counts are a cache, they must be copied because they are calculated eagerly. */
   dst.runtime->type_counts = src.runtime->type_counts;
-
-  dst.update_customdata_pointers();
 }
 
 CurvesGeometry::CurvesGeometry(const CurvesGeometry &other)
@@ -130,9 +126,6 @@ static void move_curves_geometry(CurvesGeometry &dst, CurvesGeometry &src)
   MEM_SAFE_FREE(src.curve_offsets);
 
   std::swap(dst.runtime, src.runtime);
-
-  src.update_customdata_pointers();
-  dst.update_customdata_pointers();
 }
 
 CurvesGeometry::CurvesGeometry(CurvesGeometry &&other)
@@ -306,13 +299,11 @@ void CurvesGeometry::update_curve_types()
 
 Span<float3> CurvesGeometry::positions() const
 {
-  return {(const float3 *)this->position, this->point_num};
+  return get_span_attribute<float3>(*this, ATTR_DOMAIN_POINT, ATTR_POSITION);
 }
 MutableSpan<float3> CurvesGeometry::positions_for_write()
 {
-  this->position = (float(*)[3])CustomData_duplicate_referenced_layer_named(
-      &this->point_data, CD_PROP_FLOAT3, ATTR_POSITION.c_str(), this->point_num);
-  return {(float3 *)this->position, this->point_num};
+  return get_mutable_attribute<float3>(*this, ATTR_DOMAIN_POINT, ATTR_POSITION);
 }
 
 Span<int> CurvesGeometry::offsets() const
@@ -961,7 +952,6 @@ void CurvesGeometry::resize(const int points_num, const int curves_num)
     this->curve_offsets = (int *)MEM_reallocN(this->curve_offsets, sizeof(int) * (curves_num + 1));
   }
   this->tag_topology_changed();
-  this->update_customdata_pointers();
 }
 
 void CurvesGeometry::tag_positions_changed()
@@ -1060,10 +1050,11 @@ void CurvesGeometry::transform(const float4x4 &matrix)
 
 static std::optional<bounds::MinMaxResult<float3>> curves_bounds(const CurvesGeometry &curves)
 {
-  Span<float3> positions = curves.positions();
-  if (curves.radius) {
-    Span<float> radii{curves.radius, curves.points_num()};
-    return bounds::min_max_with_radii(positions, radii);
+  const Span<float3> positions = curves.positions();
+  const VArray<float> radii = curves.attributes().lookup_or_default<float>(
+      ATTR_RADIUS, ATTR_DOMAIN_POINT, 0.0f);
+  if (!(radii.is_single() && radii.get_internal_single() == 0.0f)) {
+    return bounds::min_max_with_radii(positions, radii.get_internal_span());
   }
   return bounds::min_max(positions);
 }
@@ -1079,16 +1070,6 @@ bool CurvesGeometry::bounds_min_max(float3 &min, float3 &max) const
   return true;
 }
 
-void CurvesGeometry::update_customdata_pointers()
-{
-  this->position = (float(*)[3])CustomData_get_layer_named(
-      &this->point_data, CD_PROP_FLOAT3, ATTR_POSITION.c_str());
-  this->radius = (float *)CustomData_get_layer_named(
-      &this->point_data, CD_PROP_FLOAT, ATTR_RADIUS.c_str());
-  this->curve_type = (int8_t *)CustomData_get_layer_named(
-      &this->point_data, CD_PROP_INT8, ATTR_CURVE_TYPE.c_str());
-}
-
 static void *ensure_customdata_layer(CustomData &custom_data,
                                      const StringRefNull name,
                                      const eCustomDataType data_type,
@@ -1497,7 +1478,6 @@ void CurvesGeometry::remove_attributes_based_on_types()
   if (!this->has_curve_with_type({CURVE_TYPE_BEZIER, CURVE_TYPE_CATMULL_ROM, CURVE_TYPE_NURBS})) {
     CustomData_free_layer_named(&this->curve_data, ATTR_RESOLUTION.c_str(), curves_num);
   }
-  this->update_customdata_pointers();
 }
 
 /** \} */