[Bf-blender-cvs] [4bf74afacc1] master: Fix T94422: Shading/Normals break on array modifier caps

[Philipp Oeser]

Commit: 4bf74afacc1d1d6c975130aeb39f532de40ed603
Author: Philipp Oeser
Date:   Tue Dec 28 16:57:36 2021 +0100
Branches: master
https://developer.blender.org/rB4bf74afacc1d1d6c975130aeb39f532de40ed603

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 2f0f11ab56d..fa5149a45ba 100644
--- a/source/blender/modifiers/intern/MOD_array.c
+++ b/source/blender/modifiers/intern/MOD_array.c
@@ -285,7 +285,8 @@ 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;
@@ -305,6 +306,15 @@ 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 */
@@ -711,7 +721,8 @@ 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,
@@ -740,7 +751,8 @@ 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,