Cleanup: Store instances id attribute with other attributes

Now that we can store any dynamic attribute on the instances component,
we don't need the special case for `id`, it can just be handled by the
generic attribute storage. Mostly this just allows removing a bunch
of redundant code.

I had to add a null check for `update_custom_data_pointers` because
the instances component doesn't have any pointers to inside of
custom data.

Differential Revision: https://developer.blender.org/D13430

2 files changed, 5 insertions, 12 deletions

diff --git a/source/blender/nodes/geometry/nodes/legacy/node_geo_legacy_point_instance.cc b/source/blender/nodes/geometry/nodes/legacy/node_geo_legacy_point_instance.cc
index be8294cda90..ef35bef96aa 100644
--- a/source/blender/nodes/geometry/nodes/legacy/node_geo_legacy_point_instance.cc
+++ b/source/blender/nodes/geometry/nodes/legacy/node_geo_legacy_point_instance.cc
@@ -186,7 +186,9 @@ static void add_instances_from_component(InstancesComponent &instances,
   instances.resize(start_len + domain_size);
   MutableSpan<int> handles = instances.instance_reference_handles().slice(start_len, domain_size);
   MutableSpan<float4x4> transforms = instances.instance_transforms().slice(start_len, domain_size);
-  MutableSpan<int> instance_ids = instances.instance_ids_ensure().slice(start_len, domain_size);
+  OutputAttribute_Typed<int> instance_id_attribute =
+      instances.attribute_try_get_for_output_only<int>("id", ATTR_DOMAIN_INSTANCE);
+  MutableSpan<int> instance_ids = instance_id_attribute.as_span();
 
   /* Skip all of the randomness handling if there is only a single possible instance
    * (anything except for collection mode with "Whole Collection" turned off). */
@@ -213,6 +215,8 @@ static void add_instances_from_component(InstancesComponent &instances,
       }
     });
   }
+
+  instance_id_attribute.save();
 }
 
 static void node_geo_exec(GeoNodeExecParams params)
diff --git a/source/blender/nodes/geometry/nodes/node_geo_instance_on_points.cc b/source/blender/nodes/geometry/nodes/node_geo_instance_on_points.cc
index 637c2c59da6..4e75f1f60d9 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_instance_on_points.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_instance_on_points.cc
@@ -158,17 +158,6 @@ static void add_instances_from_component(
     }
   });
 
-  VArray<int> ids = src_component
-                        .attribute_try_get_for_read("id", ATTR_DOMAIN_POINT, CD_PROP_INT32)
-                        .typed<int>();
-  if (ids) {
-    VArray_Span<int> ids_span{ids};
-    MutableSpan<int> dst_ids = dst_component.instance_ids_ensure();
-    for (const int64_t i : selection.index_range()) {
-      dst_ids[i] = ids_span[selection[i]];
-    }
-  }
-
   if (pick_instance.is_single()) {
     if (pick_instance.get_internal_single()) {
       if (instance.has_realized_data()) {