[Bf-blender-cvs] [dd9f4e1b81b] blender-v2.83-release: Fix T94422: Shading/Normals break on array modifier caps

[Philipp Oeser]

Commit: dd9f4e1b81b1bb67c2322ca16b7fe34c7f70c974
Author: Philipp Oeser
Date:   Tue Dec 28 16:57:36 2021 +0100
Branches: blender-v2.83-release
https://developer.blender.org/rBdd9f4e1b81b1bb67c2322ca16b7fe34c7f70c974

Fix T94422: Shading/Normals break on array modifier caps

The array modifier does not necessarily tag normals dirty.
If it doesnt, normals are recalculated "internally" using the offset ob
transform. This was happening for the array items, but not for the caps.

Now do the same thing for caps.

Maniphest Tasks: T94422

Differential Revision: https://developer.blender.org/D13681

===================================================================

M	source/blender/modifiers/intern/MOD_array.c

===================================================================

diff --git a/source/blender/modifiers/intern/MOD_array.c b/source/blender/modifiers/intern/MOD_array.c
index bad1d7d3cf9..20cbe70eca3 100644
--- a/source/blender/modifiers/intern/MOD_array.c
+++ b/source/blender/modifiers/intern/MOD_array.c
@@ -279,7 +279,8 @@ static void mesh_merge_transform(Mesh *result,
                                  int cap_nloops,
                                  int cap_npolys,
                                  int *remap,
-                                 int remap_len)
+                                 int remap_len,
+                                 const bool recalc_normals_later)
 {
   int *index_orig;
   int i;
@@ -299,6 +300,15 @@ static void mesh_merge_transform(Mesh *result,
     mul_m4_v3(cap_offset, mv->co);
     /* Reset MVert flags for caps */
     mv->flag = mv->bweight = 0;
+
+    /* We have to correct normals too, if we do not tag them as dirty later! */
+    if (!recalc_normals_later) {
+      float no[3];
+      normal_short_to_float_v3(no, mv->no);
+      mul_mat3_m4_v3(cap_offset, no);
+      normalize_v3(no);
+      normal_float_to_short_v3(mv->no, no);
+    }
   }
 
   /* remap the vertex groups if necessary */
@@ -703,7 +713,8 @@ static Mesh *arrayModifier_doArray(ArrayModifierData *amd,
                          start_cap_nloops,
                          start_cap_npolys,
                          vgroup_start_cap_remap,
-                         vgroup_start_cap_remap_len);
+                         vgroup_start_cap_remap_len,
+                         use_recalc_normals);
     /* Identify doubles with first chunk */
     if (use_merge) {
       dm_mvert_map_doubles(full_doubles_map,
@@ -732,7 +743,8 @@ static Mesh *arrayModifier_doArray(ArrayModifierData *amd,
                          end_cap_nloops,
                          end_cap_npolys,
                          vgroup_end_cap_remap,
-                         vgroup_end_cap_remap_len);
+                         vgroup_end_cap_remap_len,
+                         use_recalc_normals);
     /* Identify doubles with last chunk */
     if (use_merge) {
       dm_mvert_map_doubles(full_doubles_map,