Geometry: Avoid unnecessary initialization when resizing data arrays

When resizing mesh and curves attribute storage, avoid initializing the
new memory for basic types. Also, avoid skipping "no free" layers; all
layers should be reallocated to the new size since they may be accessed.

The semantics introduced in 25237d2625078c6d1 are essential for this
change, because otherwise we don't have a way to construct non-trivial
types in the new memory.

In a basic test of the extrude node, I observed a performance
improvement of about 30%, from 55ms to 42ms.

Differential Revision: https://developer.blender.org/D15818

1 files changed, 18 insertions, 8 deletions

diff --git a/source/blender/nodes/geometry/nodes/node_geo_extrude_mesh.cc b/source/blender/nodes/geometry/nodes/node_geo_extrude_mesh.cc
index 64779494e3e..c7f4b78946d 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_extrude_mesh.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_extrude_mesh.cc
@@ -94,24 +94,24 @@ static void expand_mesh(Mesh &mesh,
                         const int loop_expand)
 {
   if (vert_expand != 0) {
-    CustomData_duplicate_referenced_layers(&mesh.vdata, mesh.totvert);
+    const int old_verts_num = mesh.totvert;
     mesh.totvert += vert_expand;
-    CustomData_realloc(&mesh.vdata, mesh.totvert);
+    CustomData_realloc(&mesh.vdata, old_verts_num, mesh.totvert);
   }
   if (edge_expand != 0) {
-    CustomData_duplicate_referenced_layers(&mesh.edata, mesh.totedge);
+    const int old_edges_num = mesh.totedge;
     mesh.totedge += edge_expand;
-    CustomData_realloc(&mesh.edata, mesh.totedge);
+    CustomData_realloc(&mesh.edata, old_edges_num, mesh.totedge);
   }
   if (poly_expand != 0) {
-    CustomData_duplicate_referenced_layers(&mesh.pdata, mesh.totpoly);
+    const int old_polys_num = mesh.totpoly;
     mesh.totpoly += poly_expand;
-    CustomData_realloc(&mesh.pdata, mesh.totpoly);
+    CustomData_realloc(&mesh.pdata, old_polys_num, mesh.totpoly);
   }
   if (loop_expand != 0) {
-    CustomData_duplicate_referenced_layers(&mesh.ldata, mesh.totloop);
+    const int old_loops_num = mesh.totloop;
     mesh.totloop += loop_expand;
-    CustomData_realloc(&mesh.ldata, mesh.totloop);
+    CustomData_realloc(&mesh.ldata, old_loops_num, mesh.totloop);
   }
 }
 
@@ -147,6 +147,7 @@ static MEdge new_edge(const int v1, const int v2)
   MEdge edge;
   edge.v1 = v1;
   edge.v2 = v2;
+  edge.crease = 0;
   edge.flag = (ME_EDGEDRAW | ME_EDGERENDER);
   return edge;
 }
@@ -156,6 +157,7 @@ static MEdge new_loose_edge(const int v1, const int v2)
   MEdge edge;
   edge.v1 = v1;
   edge.v2 = v2;
+  edge.crease = 0;
   edge.flag = ME_LOOSEEDGE;
   return edge;
 }
@@ -286,6 +288,7 @@ static void extrude_mesh_vertices(Mesh &mesh,
       for (const int i : range) {
         const float3 offset = offsets[selection[i]];
         add_v3_v3(new_verts[i].co, offset);
+        new_verts[i].flag = 0;
       }
     });
   });
@@ -608,6 +611,7 @@ static void extrude_mesh_edges(Mesh &mesh,
     threading::parallel_for(new_verts.index_range(), 1024, [&](const IndexRange range) {
       for (const int i : range) {
         add_v3_v3(new_verts[i].co, offset);
+        new_verts[i].flag = 0;
       }
     });
   }
@@ -615,6 +619,7 @@ static void extrude_mesh_edges(Mesh &mesh,
     threading::parallel_for(new_verts.index_range(), 1024, [&](const IndexRange range) {
       for (const int i : range) {
         add_v3_v3(new_verts[i].co, vert_offsets[new_vert_indices[i]]);
+        new_verts[i].flag = 0;
       }
     });
   }
@@ -996,6 +1001,10 @@ static void extrude_mesh_face_regions(Mesh &mesh,
         });
   }
 
+  for (MVert &vert : verts.slice(new_vert_range)) {
+    vert.flag = 0;
+  }
+
   MutableSpan<int> vert_orig_indices = get_orig_index_layer(mesh, ATTR_DOMAIN_POINT);
   vert_orig_indices.slice(new_vert_range).fill(ORIGINDEX_NONE);
 
@@ -1253,6 +1262,7 @@ static void extrude_individual_mesh_faces(Mesh &mesh,
       const IndexRange poly_corner_range = selected_corner_range(index_offsets, i_selection);
       for (MVert &vert : new_verts.slice(poly_corner_range)) {
         add_v3_v3(vert.co, poly_offset[poly_selection[i_selection]]);
+        vert.flag = 0;
       }
     }
   });