Geometry Nodes: Remove implicit realizing and conversion

This commit removes the implicit conversion from points to a mesh
that used to happen before the next modifier. It also removes the
implicit realizing of instances that happened before another modifier.

Now we have specific nodes for both of these operations, the
implicit conversions make less sense, and implicit instance
realizing has already been removed in other nodes.

This adds another geometry nodes modifier before modifiers that would
have realized instances implicitly before. Currently adding another
data-block during versioning after linking means that an assert needs
to be changed. That should be made unnecessary by T92333.

Differential Revision: https://developer.blender.org/D12722

3 files changed, 13 insertions, 102 deletions

diff --git a/source/blender/blenkernel/intern/DerivedMesh.cc b/source/blender/blenkernel/intern/DerivedMesh.cc
index 59e81938e79..3ec0ab9c512 100644
--- a/source/blender/blenkernel/intern/DerivedMesh.cc
+++ b/source/blender/blenkernel/intern/DerivedMesh.cc
@@ -886,33 +886,6 @@ void BKE_mesh_wrapper_deferred_finalize(Mesh *me_eval,
 }
 
 /**
- * Some modifiers don't work on geometry sets directly, but expect a single mesh as input.
- * Therefore, we convert data from the geometry set into a single mesh, so that those
- * modifiers can work on it as well.
- */
-static Mesh *prepare_geometry_set_for_mesh_modifier(Mesh *mesh, GeometrySet &r_geometry_set)
-{
-  if (!r_geometry_set.has_instances() && !r_geometry_set.has_pointcloud()) {
-    return mesh;
-  }
-
-  {
-    /* Add the mesh to the geometry set. */
-    MeshComponent &mesh_component = r_geometry_set.get_component_for_write<MeshComponent>();
-    mesh_component.replace(mesh, GeometryOwnershipType::Editable);
-  }
-  {
-    /* Combine mesh and all instances into a single mesh that can be passed to the modifier. */
-    GeometrySet new_geometry_set = blender::bke::geometry_set_realize_mesh_for_modifier(
-        r_geometry_set);
-    MeshComponent &mesh_component = new_geometry_set.get_component_for_write<MeshComponent>();
-    Mesh *new_mesh = mesh_component.release();
-    r_geometry_set = new_geometry_set;
-    return new_mesh;
-  }
-}
-
-/**
  * Modifies the given mesh and geometry set. The mesh is not passed as part of the mesh component
  * in the \a geometry_set input, it is only passed in \a input_mesh and returned in the return
  * value.
@@ -928,14 +901,7 @@ static Mesh *modifier_modify_mesh_and_geometry_set(ModifierData *md,
   Mesh *mesh_output = nullptr;
   const ModifierTypeInfo *mti = BKE_modifier_get_info((ModifierType)md->type);
   if (mti->modifyGeometrySet == nullptr) {
-    Mesh *new_input_mesh = prepare_geometry_set_for_mesh_modifier(input_mesh, geometry_set);
-    mesh_output = BKE_modifier_modify_mesh(md, &mectx, new_input_mesh);
-
-    /* The caller is responsible for freeing `input_mesh` and `mesh_output`. The intermediate
-     * `new_input_mesh` has to be freed here. */
-    if (!ELEM(new_input_mesh, input_mesh, mesh_output)) {
-      BKE_id_free(nullptr, new_input_mesh);
-    }
+    mesh_output = BKE_modifier_modify_mesh(md, &mectx, input_mesh);
   }
   else {
     /* For performance reasons, this should be called by the modifier and/or nodes themselves at
@@ -1177,14 +1143,6 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
       /* No existing verts to deform, need to build them. */
       if (!deformed_verts) {
         if (mesh_final) {
-          Mesh *mesh_final_new = prepare_geometry_set_for_mesh_modifier(mesh_final,
-                                                                        geometry_set_final);
-          if (mesh_final_new != mesh_final) {
-            BLI_assert(mesh_final != mesh_input);
-            BKE_id_free(nullptr, mesh_final);
-            mesh_final = mesh_final_new;
-          }
-
           /* Deforming a mesh, read the vertex locations
            * out of the mesh and deform them. Once done with this
            * run of deformers verts will be written back. */
diff --git a/source/blender/blenkernel/intern/geometry_set_instances.cc b/source/blender/blenkernel/intern/geometry_set_instances.cc
index d92df386575..35c6a7df2c7 100644
--- a/source/blender/blenkernel/intern/geometry_set_instances.cc
+++ b/source/blender/blenkernel/intern/geometry_set_instances.cc
@@ -224,8 +224,7 @@ void geometry_set_gather_instances_attribute_info(Span<GeometryInstanceGroup> se
   }
 }
 
-static Mesh *join_mesh_topology_and_builtin_attributes(Span<GeometryInstanceGroup> set_groups,
-                                                       const bool convert_points_to_vertices)
+static Mesh *join_mesh_topology_and_builtin_attributes(Span<GeometryInstanceGroup> set_groups)
 {
   int totverts = 0;
   int totloops = 0;
@@ -255,10 +254,6 @@ static Mesh *join_mesh_topology_and_builtin_attributes(Span<GeometryInstanceGrou
         materials.add(material);
       }
     }
-    if (convert_points_to_vertices && set.has_pointcloud()) {
-      const PointCloud &pointcloud = *set.get_pointcloud_for_read();
-      totverts += pointcloud.totpoint * tot_transforms;
-    }
   }
 
   /* Don't create an empty mesh. */
@@ -345,24 +340,6 @@ static Mesh *join_mesh_topology_and_builtin_attributes(Span<GeometryInstanceGrou
         poly_offset += mesh.totpoly;
       }
     }
-
-    const float3 point_normal{0.0f, 0.0f, 1.0f};
-    short point_normal_short[3];
-    normal_float_to_short_v3(point_normal_short, point_normal);
-
-    if (convert_points_to_vertices && set.has_pointcloud()) {
-      const PointCloud &pointcloud = *set.get_pointcloud_for_read();
-      for (const float4x4 &transform : set_group.transforms) {
-        for (const int i : IndexRange(pointcloud.totpoint)) {
-          MVert &new_vert = new_mesh->mvert[vert_offset + i];
-          const float3 old_position = pointcloud.co[i];
-          const float3 new_position = transform * old_position;
-          copy_v3_v3(new_vert.co, new_position);
-          memcpy(&new_vert.no, point_normal_short, sizeof(point_normal_short));
-        }
-        vert_offset += pointcloud.totpoint;
-      }
-    }
   }
 
   /* A possible optimization is to only tag the normals dirty when there are transforms that change
@@ -495,12 +472,9 @@ static CurveEval *join_curve_splines_and_builtin_attributes(Span<GeometryInstanc
   return new_curve;
 }
 
-static void join_instance_groups_mesh(Span<GeometryInstanceGroup> set_groups,
-                                      bool convert_points_to_vertices,
-                                      GeometrySet &result)
+static void join_instance_groups_mesh(Span<GeometryInstanceGroup> set_groups, GeometrySet &result)
 {
-  Mesh *new_mesh = join_mesh_topology_and_builtin_attributes(set_groups,
-                                                             convert_points_to_vertices);
+  Mesh *new_mesh = join_mesh_topology_and_builtin_attributes(set_groups);
   if (new_mesh == nullptr) {
     return;
   }
@@ -508,21 +482,17 @@ static void join_instance_groups_mesh(Span<GeometryInstanceGroup> set_groups,
   MeshComponent &dst_component = result.get_component_for_write<MeshComponent>();
   dst_component.replace(new_mesh);
 
-  Vector<GeometryComponentType> component_types;
-  component_types.append(GEO_COMPONENT_TYPE_MESH);
-  if (convert_points_to_vertices) {
-    component_types.append(GEO_COMPONENT_TYPE_POINT_CLOUD);
-  }
-
   /* Don't copy attributes that are stored directly in the mesh data structs. */
   Map<AttributeIDRef, AttributeKind> attributes;
   geometry_set_gather_instances_attribute_info(
       set_groups,
-      component_types,
+      {GEO_COMPONENT_TYPE_MESH},
       {"position", "material_index", "normal", "shade_smooth", "crease"},
       attributes);
-  join_attributes(
-      set_groups, component_types, attributes, static_cast<GeometryComponent &>(dst_component));
+  join_attributes(set_groups,
+                  {GEO_COMPONENT_TYPE_MESH},
+                  attributes,
+                  static_cast<GeometryComponent &>(dst_component));
 }
 
 static void join_instance_groups_pointcloud(Span<GeometryInstanceGroup> set_groups,
@@ -582,24 +552,6 @@ static void join_instance_groups_curve(Span<GeometryInstanceGroup> set_groups, G
                   static_cast<GeometryComponent &>(dst_component));
 }
 
-GeometrySet geometry_set_realize_mesh_for_modifier(const GeometrySet &geometry_set)
-{
-  if (!geometry_set.has_instances() && !geometry_set.has_pointcloud()) {
-    return geometry_set;
-  }
-
-  GeometrySet new_geometry_set = geometry_set;
-  Vector<GeometryInstanceGroup> set_groups;
-  geometry_set_gather_instances(geometry_set, set_groups);
-  join_instance_groups_mesh(set_groups, true, new_geometry_set);
-  /* Remove all instances, even though some might contain other non-mesh data. We can't really
-   * keep only non-mesh instances in general. */
-  new_geometry_set.remove<InstancesComponent>();
-  /* If there was a point cloud, it is now part of the mesh. */
-  new_geometry_set.remove<PointCloudComponent>();
-  return new_geometry_set;
-}
-
 GeometrySet geometry_set_realize_instances(const GeometrySet &geometry_set)
 {
   if (!geometry_set.has_instances()) {
@@ -610,7 +562,7 @@ GeometrySet geometry_set_realize_instances(const GeometrySet &geometry_set)
 
   Vector<GeometryInstanceGroup> set_groups;
   geometry_set_gather_instances(geometry_set, set_groups);
-  join_instance_groups_mesh(set_groups, false, new_geometry_set);
+  join_instance_groups_mesh(set_groups, new_geometry_set);
   join_instance_groups_pointcloud(set_groups, new_geometry_set);
   join_instance_groups_volume(set_groups, new_geometry_set);
   join_instance_groups_curve(set_groups, new_geometry_set);
diff --git a/source/blender/blenkernel/intern/lib_id.c b/source/blender/blenkernel/intern/lib_id.c
index 3b2d2c5d2c3..3c85ba62d07 100644
--- a/source/blender/blenkernel/intern/lib_id.c
+++ b/source/blender/blenkernel/intern/lib_id.c
@@ -1121,8 +1121,9 @@ void *BKE_libblock_alloc(Main *bmain, short type, const char *name, const int fl
       id->us = 1;
     }
     if ((flag & LIB_ID_CREATE_NO_MAIN) == 0) {
-      /* Note that 2.8x versioning has tested not to cause conflicts. */
-      BLI_assert(bmain->is_locked_for_linking == false || ELEM(type, ID_WS, ID_GR));
+      /* Note that 2.8x versioning has tested not to cause conflicts. Node trees are
+       * skipped in this check to allow adding a geometry node tree for versioning. */
+      BLI_assert(bmain->is_locked_for_linking == false || ELEM(type, ID_WS, ID_GR, ID_NT));
       ListBase *lb = which_libbase(bmain, type);
 
       BKE_main_lock(bmain);