Geometry Nodes: Separate Components Node

Implementation of T86970. This node takes a geometry input with
multiple components and outputs them by component type. Meshes,
Curves, and Point Clouds support combining multiple input instances,
while volumes will only output the first volume component input until
suitable instance realization for multiple volumes is finished.

When direct geometry instancing is implemented it will be possible to
avoid realizing instances in this node.

Differential Revision: https://developer.blender.org/D11577

1 files changed, 10 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/geometry_set_instances.cc b/source/blender/blenkernel/intern/geometry_set_instances.cc
index 847df75c8cb..97801c52cc9 100644
--- a/source/blender/blenkernel/intern/geometry_set_instances.cc
+++ b/source/blender/blenkernel/intern/geometry_set_instances.cc
@@ -650,9 +650,16 @@ static void join_instance_groups_pointcloud(Span<GeometryInstanceGroup> set_grou
 static void join_instance_groups_volume(Span<GeometryInstanceGroup> set_groups,
                                         GeometrySet &result)
 {
-  /* Not yet supported. Joining volume grids with the same name requires resampling of at least
-   * one of the grids. The cell size of the resulting volume has to be determined somehow. */
-  UNUSED_VARS(set_groups, result);
+  /* Not yet supported; for now only return the first volume. Joining volume grids with the same
+   * name requires resampling of at least one of the grids. The cell size of the resulting volume
+   * has to be determined somehow. */
+  for (const GeometryInstanceGroup &set_group : set_groups) {
+    const GeometrySet &set = set_group.geometry_set;
+    if (set.has<VolumeComponent>()) {
+      result.add(*set.get_component_for_read<VolumeComponent>());
+      return;
+    }
+  }
 }
 
 static void join_instance_groups_curve(Span<GeometryInstanceGroup> set_groups, GeometrySet &result)