Modifiers: New callbacks for reading and writing .blend files

This is part of a greater blenloader decentralization effort (T76372).
For modifiers the goal is that fewer files have to be modified when
a new modifier is added.

This patch just adds the `blendWrite` and `blendRead` callbacks to
`ModifierTypeInfo` but does not change any other code yet. In the next
steps, modifier specific code will be moved from `writefile.c` and
`readfile.c` into their corresponding `MOD_*` files.

1 files changed, 17 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_modifier.h b/source/blender/blenkernel/BKE_modifier.h
index e4cf7d44f05..766ca78dc50 100644
--- a/source/blender/blenkernel/BKE_modifier.h
+++ b/source/blender/blenkernel/BKE_modifier.h
@@ -41,6 +41,8 @@ struct ModifierData;
 struct Object;
 struct Scene;
 struct bArmature;
+struct BlendWriter;
+struct BlendDataReader;
 
 typedef enum {
   /* Should not be used, only for None modifier type */
@@ -355,6 +357,21 @@ typedef struct ModifierTypeInfo {
 
   /* Register the panel types for the modifier's UI. */
   void (*panelRegister)(struct ARegionType *region_type);
+
+  /* Is called when the modifier is written to a file. The modifier data struct itself is written
+   * already.
+   *
+   * 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);
+
+  /* Is called when the modifier is read from a file.
+   *
+   * It can be used to update pointers to arrays and other structs. Furthermore, fields that have
+   * not been written (e.g. runtime data) can be reset.
+   */
+  void (*blendRead)(struct BlendDataReader *reader, struct ModifierData *md);
 } ModifierTypeInfo;
 
 /* Used to find a modifier's panel type. */