Refactor modifiers writing code.

This changes is needed to give more control to modifiers' writing
callback when defined. It will allow to implement better culling of
needless data when writing e.g. modifiers from library overrides.

Ref. T97967.

Reviewed By: brecht, JacquesLucke

Differential Revision: https://developer.blender.org/D14939

3 files changed, 15 insertions, 9 deletions

diff --git a/source/blender/blenkernel/BKE_modifier.h b/source/blender/blenkernel/BKE_modifier.h
index 4749aab4379..866b0353d07 100644
--- a/source/blender/blenkernel/BKE_modifier.h
+++ b/source/blender/blenkernel/BKE_modifier.h
@@ -364,7 +364,9 @@ typedef struct ModifierTypeInfo {
    * This method should write any additional arrays and referenced structs that should be
    * stored in the file.
    */
-  void (*blendWrite)(struct BlendWriter *writer, const struct ModifierData *md);
+  void (*blendWrite)(struct BlendWriter *writer,
+                     const struct ID *id_owner,
+                     const struct ModifierData *md);
 
   /**
    * Is called when the modifier is read from a file.
@@ -593,7 +595,9 @@ struct Mesh *BKE_modifier_get_evaluated_mesh_from_evaluated_object(struct Object
 
 void BKE_modifier_check_uuids_unique_and_report(const struct Object *object);
 
-void BKE_modifier_blend_write(struct BlendWriter *writer, struct ListBase *modbase);
+void BKE_modifier_blend_write(struct BlendWriter *writer,
+                              const struct ID *id_owner,
+                              struct ListBase *modbase);
 void BKE_modifier_blend_read_data(struct BlendDataReader *reader,
                                   struct ListBase *lb,
                                   struct Object *ob);
diff --git a/source/blender/blenkernel/intern/modifier.c b/source/blender/blenkernel/intern/modifier.c
index 5ffd253be3b..6348d83362e 100644
--- a/source/blender/blenkernel/intern/modifier.c
+++ b/source/blender/blenkernel/intern/modifier.c
@@ -1067,7 +1067,7 @@ void BKE_modifier_check_uuids_unique_and_report(const Object *object)
   BLI_gset_free(used_uuids, NULL);
 }
 
-void BKE_modifier_blend_write(BlendWriter *writer, ListBase *modbase)
+void BKE_modifier_blend_write(BlendWriter *writer, const ID *id_owner, ListBase *modbase)
 {
   if (modbase == NULL) {
     return;
@@ -1076,7 +1076,13 @@ void BKE_modifier_blend_write(BlendWriter *writer, ListBase *modbase)
   LISTBASE_FOREACH (ModifierData *, md, modbase) {
     const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
     if (mti == NULL) {
-      return;
+      continue;
+    }
+
+    /* If the blendWrite callback is defined, it should handle the whole writing process. */
+    if (mti->blendWrite != NULL) {
+      mti->blendWrite(writer, id_owner, md);
+      continue;
     }
 
     BLO_write_struct_by_name(writer, mti->structName, md);
@@ -1162,10 +1168,6 @@ void BKE_modifier_blend_write(BlendWriter *writer, ListBase *modbase)
       writestruct(wd, DATA, MFace, collmd->numfaces, collmd->mfaces);
 #endif
     }
-
-    if (mti->blendWrite != NULL) {
-      mti->blendWrite(writer, md);
-    }
   }
 }
 
diff --git a/source/blender/blenkernel/intern/object.cc b/source/blender/blenkernel/intern/object.cc
index 7f5146f14e0..55b9951c52d 100644
--- a/source/blender/blenkernel/intern/object.cc
+++ b/source/blender/blenkernel/intern/object.cc
@@ -583,7 +583,7 @@ static void object_blend_write(BlendWriter *writer, ID *id, const void *id_addre
   }
 
   BKE_particle_system_blend_write(writer, &ob->particlesystem);
-  BKE_modifier_blend_write(writer, &ob->modifiers);
+  BKE_modifier_blend_write(writer, &ob->id, &ob->modifiers);
   BKE_gpencil_modifier_blend_write(writer, &ob->greasepencil_modifiers);
   BKE_shaderfx_blend_write(writer, &ob->shader_fx);