Mesh: Add utility to calculate deform modifier up to index

Intention is to be used to create mesh at the state which is an input
to the multires modifier.

2 files changed, 27 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_mesh_runtime.h b/source/blender/blenkernel/BKE_mesh_runtime.h
index fdddafcc71f..bdf7692b89b 100644
--- a/source/blender/blenkernel/BKE_mesh_runtime.h
+++ b/source/blender/blenkernel/BKE_mesh_runtime.h
@@ -87,6 +87,12 @@ struct Mesh *mesh_create_eval_final_view(struct Depsgraph *depsgraph,
                                          struct Object *ob,
                                          const struct CustomData_MeshMasks *dataMask);
 
+struct Mesh *mesh_create_eval_final_view_index(struct Depsgraph *depsgraph,
+                                               struct Scene *scene,
+                                               struct Object *ob,
+                                               const struct CustomData_MeshMasks *dataMask,
+                                               int index);
+
 struct Mesh *mesh_create_eval_no_deform(struct Depsgraph *depsgraph,
                                         struct Scene *scene,
                                         struct Object *ob,
diff --git a/source/blender/blenkernel/intern/DerivedMesh.c b/source/blender/blenkernel/intern/DerivedMesh.c
index 5feb51534e9..2db48e1fb13 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.c
+++ b/source/blender/blenkernel/intern/DerivedMesh.c
@@ -2013,6 +2013,27 @@ Mesh *mesh_create_eval_final_view(Depsgraph *depsgraph,
   return final;
 }
 
+Mesh *mesh_create_eval_final_view_index(Depsgraph *depsgraph,
+                                        Scene *scene,
+                                        Object *ob,
+                                        const CustomData_MeshMasks *dataMask,
+                                        int index)
+{
+  Mesh *final;
+
+  /* XXX hack
+   * psys modifier updates particle state when called during dupli-list generation,
+   * which can lead to wrong transforms. This disables particle system modifier execution.
+   */
+  ob->transflag |= OB_NO_PSYS_UPDATE;
+
+  mesh_calc_modifiers(depsgraph, scene, ob, 1, false, dataMask, index, false, false, NULL, &final);
+
+  ob->transflag &= ~OB_NO_PSYS_UPDATE;
+
+  return final;
+}
+
 Mesh *mesh_create_eval_no_deform(Depsgraph *depsgraph,
                                  Scene *scene,
                                  Object *ob,