Geometry Nodes: refactor instances component

The main goal of this refactor is to not store Object/Collection
pointers for every individual instance. Instead instances now
store a handle for the referenced data. The actual Object/Collection
pointers are stored in a new `InstanceReference` class.

This refactor also allows for some better optimizations further down
the line, because one does not have to search through all instances
anymore to find what data is instanced.

Furthermore, this refactor makes it easier to support instancing
`GeometrySet` or any other data that has to be owned by the
`InstancesComponent`.

Differential Revision: https://developer.blender.org/D11125

1 files changed, 37 insertions, 25 deletions

diff --git a/source/blender/blenkernel/intern/geometry_set_instances.cc b/source/blender/blenkernel/intern/geometry_set_instances.cc
index 7e994b32ded..a792e268d5c 100644
--- a/source/blender/blenkernel/intern/geometry_set_instances.cc
+++ b/source/blender/blenkernel/intern/geometry_set_instances.cc
@@ -149,21 +149,28 @@ static void geometry_set_collect_recursive(const GeometrySet &geometry_set,
     const InstancesComponent &instances_component =
         *geometry_set.get_component_for_read<InstancesComponent>();
 
-    Span<float4x4> transforms = instances_component.transforms();
-    Span<InstancedData> instances = instances_component.instanced_data();
-    for (const int i : instances.index_range()) {
-      const InstancedData &data = instances[i];
+    Span<float4x4> transforms = instances_component.instance_transforms();
+    Span<int> handles = instances_component.instance_reference_handles();
+    Span<InstanceReference> references = instances_component.references();
+    for (const int i : transforms.index_range()) {
+      const InstanceReference &reference = references[handles[i]];
       const float4x4 instance_transform = transform * transforms[i];
 
-      if (data.type == INSTANCE_DATA_TYPE_OBJECT) {
-        BLI_assert(data.data.object != nullptr);
-        const Object &object = *data.data.object;
-        geometry_set_collect_recursive_object(object, instance_transform, r_sets);
-      }
-      else if (data.type == INSTANCE_DATA_TYPE_COLLECTION) {
-        BLI_assert(data.data.collection != nullptr);
-        const Collection &collection = *data.data.collection;
-        geometry_set_collect_recursive_collection_instance(collection, instance_transform, r_sets);
+      switch (reference.type()) {
+        case InstanceReference::Type::Object: {
+          Object &object = reference.object();
+          geometry_set_collect_recursive_object(object, instance_transform, r_sets);
+          break;
+        }
+        case InstanceReference::Type::Collection: {
+          Collection &collection = reference.collection();
+          geometry_set_collect_recursive_collection_instance(
+              collection, instance_transform, r_sets);
+          break;
+        }
+        case InstanceReference::Type::None: {
+          break;
+        }
       }
     }
   }
@@ -267,19 +274,24 @@ static bool instances_attribute_foreach_recursive(const GeometrySet &geometry_se
     return true;
   }
 
-  for (const InstancedData &data : instances_component->instanced_data()) {
-    if (data.type == INSTANCE_DATA_TYPE_OBJECT) {
-      BLI_assert(data.data.object != nullptr);
-      const Object &object = *data.data.object;
-      if (!object_instance_attribute_foreach(object, callback, limit, count)) {
-        return false;
+  for (const InstanceReference &reference : instances_component->references()) {
+    switch (reference.type()) {
+      case InstanceReference::Type::Object: {
+        const Object &object = reference.object();
+        if (!object_instance_attribute_foreach(object, callback, limit, count)) {
+          return false;
+        }
+        break;
       }
-    }
-    else if (data.type == INSTANCE_DATA_TYPE_COLLECTION) {
-      BLI_assert(data.data.collection != nullptr);
-      const Collection &collection = *data.data.collection;
-      if (!collection_instance_attribute_foreach(collection, callback, limit, count)) {
-        return false;
+      case InstanceReference::Type::Collection: {
+        const Collection &collection = reference.collection();
+        if (!collection_instance_attribute_foreach(collection, callback, limit, count)) {
+          return false;
+        }
+        break;
+      }
+      case InstanceReference::Type::None: {
+        break;
       }
     }
   }