Geometry Nodes: Add special domain interpolation for selections

The generic domain interpolation algorithms didn't quite work for
selections. The interpolation would do unexpected things that
were different than the results in edit mode. The new behavior
is supposed to be the same as edit mode, although we also have
to handle face corner selections here.

Currently the code assumes that all boolean attributes should be
handled that way. I'm not sure of why that wouldn't be the case,
but if we ever need non-selection boolean attributes, that could
be supported too.

Differential Revision: https://developer.blender.org/D12488

1 files changed, 31 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/geometry_component_curve.cc b/source/blender/blenkernel/intern/geometry_component_curve.cc
index afafd766760..7d0537178ef 100644
--- a/source/blender/blenkernel/intern/geometry_component_curve.cc
+++ b/source/blender/blenkernel/intern/geometry_component_curve.cc
@@ -222,6 +222,37 @@ static void adapt_curve_domain_point_to_spline_impl(const CurveEval &curve,
   mixer.finalize();
 }
 
+/**
+ * A spline is selected if all of its control points were selected.
+ *
+ * \note Theoretically this interpolation does not need to compute all values at once.
+ * However, doing that makes the implementation simpler, and this can be optimized in the future if
+ * only some values are required.
+ */
+template<>
+void adapt_curve_domain_point_to_spline_impl(const CurveEval &curve,
+                                             const VArray<bool> &old_values,
+                                             MutableSpan<bool> r_values)
+{
+  const int splines_len = curve.splines().size();
+  Array<int> offsets = curve.control_point_offsets();
+  BLI_assert(r_values.size() == splines_len);
+
+  r_values.fill(true);
+
+  for (const int i_spline : IndexRange(splines_len)) {
+    const int spline_offset = offsets[i_spline];
+    const int spline_point_len = offsets[i_spline + 1] - spline_offset;
+
+    for (const int i_point : IndexRange(spline_point_len)) {
+      if (!old_values[spline_offset + i_point]) {
+        r_values[i_spline] = false;
+        break;
+      }
+    }
+  }
+}
+
 static GVArrayPtr adapt_curve_domain_point_to_spline(const CurveEval &curve, GVArrayPtr varray)
 {
   GVArrayPtr new_varray;