Geometry Nodes: Optimize selection for virtual array input

This makes calculation of selected indices slightly faster when the
input is a virtual array (the direct output of various nodes like
Face Area, etc). The utility can be helpful for other areas that
need to find selected indices besides field evaluation.

With the face area node used as a selection with 4 million faces,
the speedup is 3.51 ms to 3.39 ms, just a slight speedup.

Differential Revision: https://developer.blender.org/D15127

1 files changed, 3 insertions, 18 deletions

diff --git a/source/blender/functions/intern/field.cc b/source/blender/functions/intern/field.cc
index 47f6a0f19ca..fd5eab57d33 100644
--- a/source/blender/functions/intern/field.cc
+++ b/source/blender/functions/intern/field.cc
@@ -708,20 +708,11 @@ GPointer FieldConstant::value() const
  */
 
 static IndexMask index_mask_from_selection(const IndexMask full_mask,
-                                           VArray<bool> &selection,
+                                           const VArray<bool> &selection,
                                            ResourceScope &scope)
 {
-  if (selection.is_span()) {
-    Span<bool> span = selection.get_internal_span();
-    return index_mask_ops::find_indices_based_on_predicate(
-        full_mask, 4096, scope.construct<Vector<int64_t>>(), [&](const int curve_index) {
-          return span[curve_index];
-        });
-  }
-  return index_mask_ops::find_indices_based_on_predicate(
-      full_mask, 1024, scope.construct<Vector<int64_t>>(), [&](const int curve_index) {
-        return selection[curve_index];
-      });
+  return index_mask_ops::find_indices_from_virtual_array(
+      full_mask, selection, 1024, scope.construct<Vector<int64_t>>());
 }
 
 int FieldEvaluator::add_with_destination(GField field, GVMutableArray dst)
@@ -764,12 +755,6 @@ static IndexMask evaluate_selection(const Field<bool> &selection_field,
   if (selection_field) {
     VArray<bool> selection =
         evaluate_fields(scope, {selection_field}, full_mask, context)[0].typed<bool>();
-    if (selection.is_single()) {
-      if (selection.get_internal_single()) {
-        return full_mask;
-      }
-      return IndexRange(0);
-    }
     return index_mask_from_selection(full_mask, selection, scope);
   }
   return full_mask;