Geometry Nodes: add 'Intersecting Edges' output for boolean node

This patch adds a 'Intersecting Edges' output with a boolean selection
that only gives you the new edges on intersections.

Will work on a couple of examples next, this should make some
interesting effects possible (including getting us closer to the "bevel-
after-boolean-usecase")

To achieve this, a Vector is passed to `direct_mesh_boolean` when the
iMesh is still available (and intersecting edges appended), then from
those edge indices a selection will be stored as attribute.

Differential Revision: https://developer.blender.org/D15151

1 files changed, 4 insertions, 1 deletions

diff --git a/source/blender/blenkernel/BKE_mesh_boolean_convert.hh b/source/blender/blenkernel/BKE_mesh_boolean_convert.hh
index abaf2ab0178..441783d46a1 100644
--- a/source/blender/blenkernel/BKE_mesh_boolean_convert.hh
+++ b/source/blender/blenkernel/BKE_mesh_boolean_convert.hh
@@ -23,6 +23,8 @@ namespace blender::meshintersect {
  * \param material_remaps: An array of maps from material slot numbers in the corresponding mesh
  * to the material slot in the first mesh. It is OK for material_remaps or any of its constituent
  * arrays to be empty.
+ * \param r_intersecting_edges: Array to store indices of edges on the resulting mesh in. These
+ * 'new' edges are the result of the intersections.
  */
 Mesh *direct_mesh_boolean(Span<const Mesh *> meshes,
                           Span<const float4x4 *> transforms,
@@ -30,6 +32,7 @@ Mesh *direct_mesh_boolean(Span<const Mesh *> meshes,
                           Span<Array<short>> material_remaps,
                           bool use_self,
                           bool hole_tolerant,
-                          int boolean_mode);
+                          int boolean_mode,
+                          Vector<int> *r_intersecting_edges);
 
 }  // namespace blender::meshintersect