Mesh: Move hide flags to generic attributes

This commit moves the hide status of mesh vertices, edges, and faces
from the `ME_FLAG` to optional generic boolean attributes. Storing this
data as generic attributes can significantly simplify and improve code,
as described in T95965.

The attributes are called `.hide_vert`, `.hide_edge`, and `.hide_poly`,
using the attribute name semantics discussed in T97452. The `.` prefix
means they are "UI attributes", so they still contain original data
edited by users, but they aren't meant to be accessed procedurally by
the user in arbitrary situations. They are also be hidden in the
spreadsheet and the attribute list by default,

Until 4.0, the attributes are still written to and read from the mesh
in the old way, so neither forward nor backward compatibility are
affected. This means memory requirements will be increased by one byte
per element when the hide status is used. When the flags are removed
completely, requirements will decrease when hiding is unused.

Further notes:
 * Some code can be further simplified to skip some processing when the
   hide attributes don't exist.
 * The data is still stored in flags for `BMesh`, necessitating some
   complexity in the conversion to and from `Mesh`.
 * Access to the "hide" property of mesh elements in RNA is slower.
   The separate boolean arrays should be used where possible.

Ref T95965

Differential Revision: https://developer.blender.org/D14685

1 files changed, 66 insertions, 3 deletions

diff --git a/source/blender/makesrna/intern/rna_mesh.c b/source/blender/makesrna/intern/rna_mesh.c
index 9aef19c8230..bdc96f6dec1 100644
--- a/source/blender/makesrna/intern/rna_mesh.c
+++ b/source/blender/makesrna/intern/rna_mesh.c
@@ -356,6 +356,27 @@ static void rna_MeshVertex_normal_get(PointerRNA *ptr, float *value)
   copy_v3_v3(value, vert_normals[index]);
 }
 
+static bool rna_MeshVertex_hide_get(PointerRNA *ptr)
+{
+  const Mesh *mesh = rna_mesh(ptr);
+  const bool *hide_vert = (const bool *)CustomData_get_layer_named(
+      &mesh->vdata, CD_PROP_BOOL, ".hide_vert");
+  const int index = (const MVert *)ptr->data - mesh->mvert;
+  BLI_assert(index >= 0);
+  BLI_assert(index < mesh->totvert);
+  return hide_vert[index];
+}
+
+static void rna_MeshVertex_hide_set(PointerRNA *ptr, bool value)
+{
+  Mesh *mesh = rna_mesh(ptr);
+  bool *hide_vert = (bool *)CustomData_get_layer_named(&mesh->vdata, CD_PROP_BOOL, ".hide_vert");
+  const int index = (const MVert *)ptr->data - mesh->mvert;
+  BLI_assert(index >= 0);
+  BLI_assert(index < mesh->totvert);
+  hide_vert[index] = value;
+}
+
 static float rna_MeshVertex_bevel_weight_get(PointerRNA *ptr)
 {
   MVert *mvert = (MVert *)ptr->data;
@@ -464,6 +485,27 @@ static void rna_MeshPolygon_normal_get(PointerRNA *ptr, float *values)
   BKE_mesh_calc_poly_normal(mp, me->mloop + mp->loopstart, me->mvert, values);
 }
 
+static bool rna_MeshPolygon_hide_get(PointerRNA *ptr)
+{
+  const Mesh *mesh = rna_mesh(ptr);
+  const bool *hide_poly = (const bool *)CustomData_get_layer_named(
+      &mesh->pdata, CD_PROP_BOOL, ".hide_poly");
+  const int index = (const MPoly *)ptr->data - mesh->mpoly;
+  BLI_assert(index >= 0);
+  BLI_assert(index < mesh->totpoly);
+  return hide_poly[index];
+}
+
+static void rna_MeshPolygon_hide_set(PointerRNA *ptr, bool value)
+{
+  Mesh *mesh = rna_mesh(ptr);
+  bool *hide_poly = (bool *)CustomData_get_layer_named(&mesh->pdata, CD_PROP_BOOL, ".hide_poly");
+  const int index = (const MPoly *)ptr->data - mesh->mpoly;
+  BLI_assert(index >= 0);
+  BLI_assert(index < mesh->totpoly);
+  hide_poly[index] = value;
+}
+
 static void rna_MeshPolygon_center_get(PointerRNA *ptr, float *values)
 {
   Mesh *me = rna_mesh(ptr);
@@ -1188,6 +1230,27 @@ static int rna_MeshEdge_index_get(PointerRNA *ptr)
   return (int)(edge - me->medge);
 }
 
+static bool rna_MeshEdge_hide_get(PointerRNA *ptr)
+{
+  const Mesh *mesh = rna_mesh(ptr);
+  const bool *hide_edge = (const bool *)CustomData_get_layer_named(
+      &mesh->pdata, CD_PROP_BOOL, ".hide_edge");
+  const int index = (const MEdge *)ptr->data - mesh->medge;
+  BLI_assert(index >= 0);
+  BLI_assert(index < mesh->totedge);
+  return hide_edge[index];
+}
+
+static void rna_MeshEdge_hide_set(PointerRNA *ptr, bool value)
+{
+  Mesh *mesh = rna_mesh(ptr);
+  bool *hide_edge = (bool *)CustomData_get_layer_named(&mesh->edata, CD_PROP_BOOL, ".hide_edge");
+  const int index = (const MEdge *)ptr->data - mesh->medge;
+  BLI_assert(index >= 0);
+  BLI_assert(index < mesh->totedge);
+  hide_edge[index] = value;
+}
+
 static int rna_MeshLoopTriangle_index_get(PointerRNA *ptr)
 {
   Mesh *me = rna_mesh(ptr);
@@ -1830,8 +1893,8 @@ static void rna_def_mvert(BlenderRNA *brna)
   RNA_def_property_update(prop, 0, "rna_Mesh_update_select");
 
   prop = RNA_def_property(srna, "hide", PROP_BOOLEAN, PROP_NONE);
-  RNA_def_property_boolean_sdna(prop, NULL, "flag", ME_HIDE);
   RNA_def_property_ui_text(prop, "Hide", "");
+  RNA_def_property_boolean_funcs(prop, "rna_MeshVertex_hide_get", "rna_MeshVertex_hide_set");
   RNA_def_property_update(prop, 0, "rna_Mesh_update_select");
 
   prop = RNA_def_property(srna, "bevel_weight", PROP_FLOAT, PROP_NONE);
@@ -1906,8 +1969,8 @@ static void rna_def_medge(BlenderRNA *brna)
   RNA_def_property_update(prop, 0, "rna_Mesh_update_select");
 
   prop = RNA_def_property(srna, "hide", PROP_BOOLEAN, PROP_NONE);
-  RNA_def_property_boolean_sdna(prop, NULL, "flag", ME_HIDE);
   RNA_def_property_ui_text(prop, "Hide", "");
+  RNA_def_property_boolean_funcs(prop, "rna_MeshEdge_hide_get", "rna_MeshEdge_hide_set");
   RNA_def_property_update(prop, 0, "rna_Mesh_update_select");
 
   prop = RNA_def_property(srna, "use_seam", PROP_BOOLEAN, PROP_NONE);
@@ -2119,8 +2182,8 @@ static void rna_def_mpolygon(BlenderRNA *brna)
   RNA_def_property_update(prop, 0, "rna_Mesh_update_select");
 
   prop = RNA_def_property(srna, "hide", PROP_BOOLEAN, PROP_NONE);
-  RNA_def_property_boolean_sdna(prop, NULL, "flag", ME_HIDE);
   RNA_def_property_ui_text(prop, "Hide", "");
+  RNA_def_property_boolean_funcs(prop, "rna_MeshPolygon_hide_get", "rna_MeshPolygon_hide_set");
   RNA_def_property_update(prop, 0, "rna_Mesh_update_select");
 
   prop = RNA_def_property(srna, "use_smooth", PROP_BOOLEAN, PROP_NONE);