OpenSubdiv: Optimize faces storage in mesh topology

Avoid per-face pointer and allocation: store everything as continuous
arrays.

Memory footprint for 1.5M faces:

- Theoretical worst case (all vertices and edges have crease) memory
  goes down from 114 MiB to 96 MiB (15% improvement).

  This case is not currently achievable since Blender does not expose
  vertex crease yet.

- Current real life worst case (all edges have crease) memory goes
  down from 108 MiB to 90 MiB (17% improvement).

- Best case (no creases at all) memory goes down from 96 MiB to 78 MiB
  (19% improvement).

1 files changed, 13 insertions, 10 deletions

diff --git a/intern/opensubdiv/internal/topology/mesh_topology_test.cc b/intern/opensubdiv/internal/topology/mesh_topology_test.cc
index e80dab38fa3..5fb58c37add 100644
--- a/intern/opensubdiv/internal/topology/mesh_topology_test.cc
+++ b/intern/opensubdiv/internal/topology/mesh_topology_test.cc
@@ -27,6 +27,7 @@ TEST(MeshTopology, TrivialVertexSharpness)
   MeshTopology mesh_topology;
 
   mesh_topology.setNumVertices(3);
+  mesh_topology.finishResizeTopology();
 
   mesh_topology.setVertexSharpness(0, 0.1f);
   mesh_topology.setVertexSharpness(1, 0.2f);
@@ -42,6 +43,7 @@ TEST(MeshTopology, TrivialEdgeSharpness)
 
   mesh_topology.setNumVertices(8);
   mesh_topology.setNumEdges(3);
+  mesh_topology.finishResizeTopology();
 
   mesh_topology.setEdgeVertexIndices(0, 0, 1);
   mesh_topology.setEdgeVertexIndices(1, 1, 2);
@@ -60,29 +62,30 @@ TEST(MeshTopology, TrivialFaceTopology)
   MeshTopology mesh_topology;
 
   mesh_topology.setNumFaces(3);
+  mesh_topology.setNumFaceVertices(0, 4);
+  mesh_topology.setNumFaceVertices(1, 3);
+  mesh_topology.setNumFaceVertices(2, 5);
+  mesh_topology.finishResizeTopology();
+
+  EXPECT_EQ(mesh_topology.getNumFaceVertices(0), 4);
+  EXPECT_EQ(mesh_topology.getNumFaceVertices(1), 3);
+  EXPECT_EQ(mesh_topology.getNumFaceVertices(2), 5);
 
   {
-    mesh_topology.setNumFaceVertices(0, 4);
     int vertex_indices[] = {0, 1, 2, 3};
-    mesh_topology.setFaceVertexIndices(0, vertex_indices);
+    mesh_topology.setFaceVertexIndices(0, 4, vertex_indices);
   }
 
   {
-    mesh_topology.setNumFaceVertices(1, 3);
     int vertex_indices[] = {4, 5, 6};
-    mesh_topology.setFaceVertexIndices(1, vertex_indices);
+    mesh_topology.setFaceVertexIndices(1, 3, vertex_indices);
   }
 
   {
-    mesh_topology.setNumFaceVertices(2, 5);
     int vertex_indices[] = {7, 8, 9, 10, 11};
-    mesh_topology.setFaceVertexIndices(2, vertex_indices);
+    mesh_topology.setFaceVertexIndices(2, 5, vertex_indices);
   }
 
-  EXPECT_EQ(mesh_topology.getNumFaceVertices(0), 4);
-  EXPECT_EQ(mesh_topology.getNumFaceVertices(1), 3);
-  EXPECT_EQ(mesh_topology.getNumFaceVertices(2), 5);
-
   EXPECT_TRUE(mesh_topology.isFaceVertexIndicesEqual(0, {{0, 1, 2, 3}}));
   EXPECT_FALSE(mesh_topology.isFaceVertexIndicesEqual(0, {{10, 1, 2, 3}}));
   EXPECT_FALSE(mesh_topology.isFaceVertexIndicesEqual(0, {{0, 1, 2}}));