Fix T62941 Subdivision Modifier Showing all face dots

Previously in 2.79 we were using a specialized drawing using derivedMesh.

Now the subsurf modifier tag each center vertex as facedot and let the
DRWManager pick it up.

Some modifiers (deforming ones) do not clear the tag so we can use this
technique even if there is deforming modifiers after subsurf modifiers.

1 files changed, 30 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/subdiv_mesh.c b/source/blender/blenkernel/intern/subdiv_mesh.c
index 947f51b4ff9..75e05f8ffab 100644
--- a/source/blender/blenkernel/intern/subdiv_mesh.c
+++ b/source/blender/blenkernel/intern/subdiv_mesh.c
@@ -570,6 +570,8 @@ static void evaluate_vertex_and_apply_displacement_copy(const SubdivMeshContext
     normalize_v3(N);
     normal_float_to_short_v3(subdiv_vert->no, N);
   }
+  /* Remove facedot flag. This can happen if there is more than one subsurf modifier. */
+  subdiv_vert->flag &= ~ME_VERT_FACEDOT;
 }
 
 static void evaluate_vertex_and_apply_displacement_interpolate(
@@ -719,6 +721,31 @@ static void subdiv_mesh_vertex_edge(const SubdivForeachContext *foreach_context,
       ctx, ptex_face_index, u, v, &tls->vertex_interpolation, subdiv_vert);
 }
 
+static bool subdiv_mesh_is_center_vertex(const MPoly *coarse_poly, const float u, const float v)
+{
+  if (coarse_poly->totloop == 4) {
+    if (u == 0.5f && v == 0.5f) {
+      return true;
+    }
+  }
+  else {
+    if (u == 1.0f && v == 1.0f) {
+      return true;
+    }
+  }
+  return false;
+}
+
+static void subdiv_mesh_tag_center_vertex(const MPoly *coarse_poly,
+                                          MVert *subdiv_vert,
+                                          const float u,
+                                          const float v)
+{
+  if (subdiv_mesh_is_center_vertex(coarse_poly, u, v)) {
+    subdiv_vert->flag |= ME_VERT_FACEDOT;
+  }
+}
+
 static void subdiv_mesh_vertex_inner(const SubdivForeachContext *foreach_context,
                                      void *tls_v,
                                      const int ptex_face_index,
@@ -741,6 +768,7 @@ static void subdiv_mesh_vertex_inner(const SubdivForeachContext *foreach_context
   subdiv_vertex_data_interpolate(ctx, subdiv_vert, &tls->vertex_interpolation, u, v);
   eval_final_point_and_vertex_normal(
       subdiv, ptex_face_index, u, v, subdiv_vert->co, subdiv_vert->no);
+  subdiv_mesh_tag_center_vertex(coarse_poly, subdiv_vert, u, v);
 }
 
 /* =============================================================================
@@ -1098,8 +1126,8 @@ static void setup_foreach_callbacks(const SubdivMeshContext *subdiv_context,
     foreach_context->vertex_every_edge = subdiv_mesh_vertex_every_edge;
   }
   else {
-    foreach_context->vertex_every_corner = NULL;
-    foreach_context->vertex_every_edge = NULL;
+    foreach_context->vertex_every_corner = subdiv_mesh_vertex_every_corner;
+    foreach_context->vertex_every_edge = subdiv_mesh_vertex_every_edge;
   }
   foreach_context->vertex_corner = subdiv_mesh_vertex_corner;
   foreach_context->vertex_edge = subdiv_mesh_vertex_edge;