Fix T95334: Crash with no vertex normals in multires bake

This is partially caused by a stupid mistake in cfa53e0fbeed7178c78
where I missed initializing the `vert_normals` pointer in
`MResolvePixelData`. It's also caused by questionable assumptions
from DerivedMesh code that vertex normals would be valid.

The fix used here is to create a temporary mesh with the data necessary
to compute vertex normals, and ensure them here. This is used because
normal calculation is only implemented for `Mesh` and edit mesh, not
`DerivedMesh`. While this might not be great for performance, it's
potentially aligned with future refactoring of this code to remove
`DerivedMesh` completely. Since this is one of the last places the data
structure is used, that would be a great improvement.

Differential Revision: https://developer.blender.org/D13960

1 files changed, 0 insertions, 26 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.cc b/source/blender/blenkernel/intern/DerivedMesh.cc
index b9372ceed08..6056b69b5c8 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.cc
+++ b/source/blender/blenkernel/intern/DerivedMesh.cc
@@ -2137,32 +2137,6 @@ void mesh_get_mapped_verts_coords(Mesh *me_eval, float (*r_cos)[3], const int to
   }
 }
 
-void DM_calc_loop_tangents(DerivedMesh *dm,
-                           bool calc_active_tangent,
-                           const char (*tangent_names)[MAX_NAME],
-                           int tangent_names_len)
-{
-  BKE_mesh_calc_loop_tangent_ex(
-      dm->getVertArray(dm),
-      dm->getPolyArray(dm),
-      dm->getNumPolys(dm),
-      dm->getLoopArray(dm),
-      dm->getLoopTriArray(dm),
-      dm->getNumLoopTri(dm),
-      &dm->loopData,
-      calc_active_tangent,
-      tangent_names,
-      tangent_names_len,
-      (const float(*)[3])CustomData_get_layer(&dm->vertData, CD_NORMAL),
-      (const float(*)[3])CustomData_get_layer(&dm->polyData, CD_NORMAL),
-      (const float(*)[3])dm->getLoopDataArray(dm, CD_NORMAL),
-      (const float(*)[3])dm->getVertDataArray(dm, CD_ORCO), /* may be nullptr */
-      /* result */
-      &dm->loopData,
-      dm->getNumLoops(dm),
-      &dm->tangent_mask);
-}
-
 static void mesh_init_origspace(Mesh *mesh)
 {
   const float default_osf[4][2] = {{0, 0}, {1, 0}, {1, 1}, {0, 1}};