Mesh: Add an explicit "positions changed" function

We store various lazily calculated caches on meshes, some of which
depend on the vertex positions staying the same. The current API to
invalidate these caches is a bit confusing. With an explicit set of
functions modeled after the functions in `BKE_node_tree_update.h`,
it becomes clear which function to call. This may become more
important if more lazy caches are added in the future.

Differential Revision: https://developer.blender.org/D14760

7 files changed, 43 insertions, 15 deletions

diff --git a/source/blender/blenkernel/BKE_mesh.h b/source/blender/blenkernel/BKE_mesh.h
index 23ec69babc8..8e038a1d3d9 100644
--- a/source/blender/blenkernel/BKE_mesh.h
+++ b/source/blender/blenkernel/BKE_mesh.h
@@ -52,6 +52,18 @@ extern "C" {
 #  define BKE_MESH_OMP_LIMIT 10000
 #endif
 
+/*  mesh_runtime.cc  */
+
+/**
+ * Call after changing vertex positions to tag lazily calculated caches for recomputation.
+ */
+void BKE_mesh_tag_coords_changed(struct Mesh *mesh);
+
+/**
+ * Call after moving every mesh vertex by the same translation.
+ */
+void BKE_mesh_tag_coords_changed_uniformly(struct Mesh *mesh);
+
 /* *** mesh.c *** */
 
 struct BMesh *BKE_mesh_to_bmesh_ex(const struct Mesh *me,
diff --git a/source/blender/blenkernel/intern/cloth.c b/source/blender/blenkernel/intern/cloth.c
index ab9a27a3996..8622174231c 100644
--- a/source/blender/blenkernel/intern/cloth.c
+++ b/source/blender/blenkernel/intern/cloth.c
@@ -1171,7 +1171,7 @@ static Mesh *cloth_make_rest_mesh(ClothModifierData *clmd, Mesh *mesh)
   for (unsigned i = 0; i < mesh->totvert; i++, verts++) {
     copy_v3_v3(mvert[i].co, verts->xrest);
   }
-  BKE_mesh_normals_tag_dirty(new_mesh);
+  BKE_mesh_tag_coords_changed(new_mesh);
 
   return new_mesh;
 }
diff --git a/source/blender/blenkernel/intern/dynamicpaint.c b/source/blender/blenkernel/intern/dynamicpaint.c
index e5bb70f8cda..a4262e08e39 100644
--- a/source/blender/blenkernel/intern/dynamicpaint.c
+++ b/source/blender/blenkernel/intern/dynamicpaint.c
@@ -2024,13 +2024,13 @@ static Mesh *dynamicPaint_Modifier_apply(DynamicPaintModifierData *pmd, Object *
             settings.use_threading = (sData->total_points > 1000);
             BLI_task_parallel_range(
                 0, sData->total_points, &data, dynamic_paint_apply_surface_wave_cb, &settings);
-            BKE_mesh_normals_tag_dirty(result);
+            BKE_mesh_tag_coords_changed(result);
           }
 
           /* displace */
           if (surface->type == MOD_DPAINT_SURFACE_T_DISPLACE) {
             dynamicPaint_applySurfaceDisplace(surface, result);
-            BKE_mesh_normals_tag_dirty(result);
+            BKE_mesh_tag_coords_changed(result);
           }
         }
       }
diff --git a/source/blender/blenkernel/intern/geometry_component_mesh.cc b/source/blender/blenkernel/intern/geometry_component_mesh.cc
index 8a021e596bd..88ea1af8a8d 100644
--- a/source/blender/blenkernel/intern/geometry_component_mesh.cc
+++ b/source/blender/blenkernel/intern/geometry_component_mesh.cc
@@ -864,11 +864,11 @@ static void set_vertex_position(MVert &vert, float3 position)
   copy_v3_v3(vert.co, position);
 }
 
-static void tag_normals_dirty_when_writing_position(GeometryComponent &component)
+static void tag_component_positions_changed(GeometryComponent &component)
 {
   Mesh *mesh = get_mesh_from_component_for_write(component);
   if (mesh != nullptr) {
-    BKE_mesh_normals_tag_dirty(mesh);
+    BKE_mesh_tag_coords_changed(mesh);
   }
 }
 
@@ -1213,7 +1213,7 @@ static ComponentAttributeProviders create_attribute_providers_for_mesh()
       point_access,
       make_derived_read_attribute<MVert, float3, get_vertex_position>,
       make_derived_write_attribute<MVert, float3, get_vertex_position, set_vertex_position>,
-      tag_normals_dirty_when_writing_position);
+      tag_component_positions_changed);
 
   static NormalAttributeProvider normal;
 
diff --git a/source/blender/blenkernel/intern/mesh.cc b/source/blender/blenkernel/intern/mesh.cc
index 7c86aff6624..ffbd824712a 100644
--- a/source/blender/blenkernel/intern/mesh.cc
+++ b/source/blender/blenkernel/intern/mesh.cc
@@ -1684,7 +1684,7 @@ void BKE_mesh_transform(Mesh *me, const float mat[4][4], bool do_keys)
       mul_m3_v3(m3, *lnors);
     }
   }
-  BKE_mesh_normals_tag_dirty(me);
+  BKE_mesh_tag_coords_changed(me);
 }
 
 void BKE_mesh_translate(Mesh *me, const float offset[3], const bool do_keys)
@@ -1706,6 +1706,7 @@ void BKE_mesh_translate(Mesh *me, const float offset[3], const bool do_keys)
       }
     }
   }
+  BKE_mesh_tag_coords_changed_uniformly(me);
 }
 
 void BKE_mesh_tessface_ensure(Mesh *mesh)
@@ -1904,7 +1905,7 @@ void BKE_mesh_vert_coords_apply(Mesh *mesh, const float (*vert_coords)[3])
   for (int i = 0; i < mesh->totvert; i++, mv++) {
     copy_v3_v3(mv->co, vert_coords[i]);
   }
-  BKE_mesh_normals_tag_dirty(mesh);
+  BKE_mesh_tag_coords_changed(mesh);
 }
 
 void BKE_mesh_vert_coords_apply_with_mat4(Mesh *mesh,
@@ -1918,7 +1919,7 @@ void BKE_mesh_vert_coords_apply_with_mat4(Mesh *mesh,
   for (int i = 0; i < mesh->totvert; i++, mv++) {
     mul_v3_m4v3(mv->co, mat, vert_coords[i]);
   }
-  BKE_mesh_normals_tag_dirty(mesh);
+  BKE_mesh_tag_coords_changed(mesh);
 }
 
 void BKE_mesh_calc_normals_split_ex(Mesh *mesh, MLoopNorSpaceArray *r_lnors_spacearr)
diff --git a/source/blender/blenkernel/intern/mesh_runtime.cc b/source/blender/blenkernel/intern/mesh_runtime.cc
index 90e9a2a2ff6..d4bc47d5fd4 100644
--- a/source/blender/blenkernel/intern/mesh_runtime.cc
+++ b/source/blender/blenkernel/intern/mesh_runtime.cc
@@ -244,11 +244,8 @@ bool BKE_mesh_runtime_clear_edit_data(Mesh *mesh)
 
 void BKE_mesh_runtime_clear_geometry(Mesh *mesh)
 {
-  if (mesh->runtime.bvh_cache) {
-    bvhcache_free(mesh->runtime.bvh_cache);
-    mesh->runtime.bvh_cache = nullptr;
-  }
-  MEM_SAFE_FREE(mesh->runtime.looptris.array);
+  BKE_mesh_tag_coords_changed(mesh);
+
   /* TODO(sergey): Does this really belong here? */
   if (mesh->runtime.subdiv_ccg != nullptr) {
     BKE_subdiv_ccg_destroy(mesh->runtime.subdiv_ccg);
@@ -259,6 +256,24 @@ void BKE_mesh_runtime_clear_geometry(Mesh *mesh)
   MEM_SAFE_FREE(mesh->runtime.subsurf_face_dot_tags);
 }
 
+void BKE_mesh_tag_coords_changed(Mesh *mesh)
+{
+  BKE_mesh_normals_tag_dirty(mesh);
+  MEM_SAFE_FREE(mesh->runtime.looptris.array);
+  if (mesh->runtime.bvh_cache) {
+    bvhcache_free(mesh->runtime.bvh_cache);
+    mesh->runtime.bvh_cache = nullptr;
+  }
+}
+
+void BKE_mesh_tag_coords_changed_uniformly(Mesh *mesh)
+{
+  BKE_mesh_tag_coords_changed(mesh);
+  /* The normals didn't change, since all vertices moved by the same amount. */
+  BKE_mesh_poly_normals_clear_dirty(mesh);
+  BKE_mesh_vertex_normals_clear_dirty(mesh);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
diff --git a/source/blender/blenkernel/intern/multires_reshape_apply_base.c b/source/blender/blenkernel/intern/multires_reshape_apply_base.c
index 837b64affa8..f7d29806353 100644
--- a/source/blender/blenkernel/intern/multires_reshape_apply_base.c
+++ b/source/blender/blenkernel/intern/multires_reshape_apply_base.c
@@ -156,7 +156,7 @@ void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape
   /* Vertices were moved around, need to update normals after all the vertices are updated
    * Probably this is possible to do in the loop above, but this is rather tricky because
    * we don't know all needed vertices' coordinates there yet. */
-  BKE_mesh_normals_tag_dirty(base_mesh);
+  BKE_mesh_tag_coords_changed(base_mesh);
 }
 
 void multires_reshape_apply_base_refine_from_base(MultiresReshapeContext *reshape_context)