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, 20 insertions, 16 deletions

diff --git a/source/blender/blenkernel/intern/object_dupli.cc b/source/blender/blenkernel/intern/object_dupli.cc
index 835b62c06bf..768fa9373c1 100644
--- a/source/blender/blenkernel/intern/object_dupli.cc
+++ b/source/blender/blenkernel/intern/object_dupli.cc
@@ -842,38 +842,38 @@ static void make_duplis_instances_component(const DupliContext *ctx)
     return;
   }
 
-  Span<float4x4> instance_offset_matrices = component->transforms();
+  Span<float4x4> instance_offset_matrices = component->instance_transforms();
+  Span<int> instance_reference_handles = component->instance_reference_handles();
   Span<int> almost_unique_ids = component->almost_unique_ids();
-  Span<InstancedData> instanced_data = component->instanced_data();
+  Span<InstanceReference> references = component->references();
 
-  for (int i = 0; i < component->instances_amount(); i++) {
-    const InstancedData &data = instanced_data[i];
+  for (int64_t i : instance_offset_matrices.index_range()) {
+    const InstanceReference &reference = references[instance_reference_handles[i]];
     const int id = almost_unique_ids[i];
 
-    if (data.type == INSTANCE_DATA_TYPE_OBJECT) {
-      Object *object = data.data.object;
-      if (object != nullptr) {
+    switch (reference.type()) {
+      case InstanceReference::Type::Object: {
+        Object &object = reference.object();
         float matrix[4][4];
         mul_m4_m4m4(matrix, ctx->object->obmat, instance_offset_matrices[i].values);
-        make_dupli(ctx, object, matrix, id);
+        make_dupli(ctx, &object, matrix, id);
 
         float space_matrix[4][4];
-        mul_m4_m4m4(space_matrix, instance_offset_matrices[i].values, object->imat);
+        mul_m4_m4m4(space_matrix, instance_offset_matrices[i].values, object.imat);
         mul_m4_m4_pre(space_matrix, ctx->object->obmat);
-        make_recursive_duplis(ctx, object, space_matrix, id);
+        make_recursive_duplis(ctx, &object, space_matrix, id);
+        break;
       }
-    }
-    else if (data.type == INSTANCE_DATA_TYPE_COLLECTION) {
-      Collection *collection = data.data.collection;
-      if (collection != nullptr) {
+      case InstanceReference::Type::Collection: {
+        Collection &collection = reference.collection();
         float collection_matrix[4][4];
         unit_m4(collection_matrix);
-        sub_v3_v3(collection_matrix[3], collection->instance_offset);
+        sub_v3_v3(collection_matrix[3], collection.instance_offset);
         mul_m4_m4_pre(collection_matrix, instance_offset_matrices[i].values);
         mul_m4_m4_pre(collection_matrix, ctx->object->obmat);
 
         eEvaluationMode mode = DEG_get_mode(ctx->depsgraph);
-        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (collection, object, mode) {
+        FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_BEGIN (&collection, object, mode) {
           if (object == ctx->object) {
             continue;
           }
@@ -885,6 +885,10 @@ static void make_duplis_instances_component(const DupliContext *ctx)
           make_recursive_duplis(ctx, object, collection_matrix, id);
         }
         FOREACH_COLLECTION_VISIBLE_OBJECT_RECURSIVE_END;
+        break;
+      }
+      case InstanceReference::Type::None: {
+        break;
       }
     }
   }