1 files changed, 132 insertions, 0 deletions
diff --git a/source/blender/nodes/geometry/nodes/node_geo_curve_reverse.cc b/source/blender/nodes/geometry/nodes/node_geo_curve_reverse.cc
new file mode 100644
index 00000000000..e92d22a6064
--- /dev/null
+++ b/source/blender/nodes/geometry/nodes/node_geo_curve_reverse.cc
@@ -0,0 +1,132 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include "BLI_task.hh"
+
+#include "BKE_spline.hh"
+
+#include "node_geometry_util.hh"
+
+static bNodeSocketTemplate geo_node_curve_reverse_in[] = {
+    {SOCK_GEOMETRY, N_("Curve")},
+    {SOCK_STRING, N_("Selection")},
+    {-1, ""},
+};
+
+static bNodeSocketTemplate geo_node_curve_reverse_out[] = {
+    {SOCK_GEOMETRY, N_("Curve")},
+    {-1, ""},
+};
+
+namespace blender::nodes {
+
+/**
+ * Reverse the data in a MutableSpan object.
+ */
+template<typename T> static void reverse_data(MutableSpan<T> r_data)
+{
+  const int size = r_data.size();
+  for (const int i : IndexRange(size / 2)) {
+    std::swap(r_data[size - 1 - i], r_data[i]);
+  }
+}
+
+/**
+ * Reverse and Swap the data between 2 MutableSpans.
+ */
+template<typename T> static void reverse_data(MutableSpan<T> left, MutableSpan<T> right)
+{
+  BLI_assert(left.size() == right.size());
+  const int size = left.size();
+
+  for (const int i : IndexRange(size / 2 + size % 2)) {
+    std::swap(left[i], right[size - 1 - i]);
+    std::swap(right[i], left[size - 1 - i]);
+  }
+}
+
+static void geo_node_curve_reverse_exec(GeoNodeExecParams params)
+{
+  GeometrySet geometry_set = params.extract_input<GeometrySet>("Curve");
+  geometry_set = bke::geometry_set_realize_instances(geometry_set);
+  if (!geometry_set.has_curve()) {
+    params.set_output("Curve", geometry_set);
+    return;
+  }
+
+  /* Retrieve data for write access so we can avoid new allocations for the reversed data. */
+  CurveComponent &curve_component = geometry_set.get_component_for_write<CurveComponent>();
+  CurveEval &curve = *curve_component.get_for_write();
+  MutableSpan<SplinePtr> splines = curve.splines();
+
+  const std::string selection_name = params.extract_input<std::string>("Selection");
+  GVArray_Typed<bool> selection = curve_component.attribute_get_for_read(
+      selection_name, ATTR_DOMAIN_CURVE, true);
+
+  threading::parallel_for(splines.index_range(), 128, [&](IndexRange range) {
+    for (const int i : range) {
+      if (!selection[i]) {
+        continue;
+      }
+
+      reverse_data<float3>(splines[i]->positions());
+      reverse_data<float>(splines[i]->radii());
+      reverse_data<float>(splines[i]->tilts());
+
+      splines[i]->attributes.foreach_attribute(
+          [&](StringRefNull name, const AttributeMetaData &meta_data) {
+            std::optional<blender::fn::GMutableSpan> output_attribute =
+                splines[i]->attributes.get_for_write(name);
+            if (!output_attribute) {
+              BLI_assert_unreachable();
+              return false;
+            }
+            attribute_math::convert_to_static_type(meta_data.data_type, [&](auto dummy) {
+              using T = decltype(dummy);
+              reverse_data(output_attribute->typed<T>());
+            });
+            return true;
+          },
+          ATTR_DOMAIN_POINT);
+
+      /* Deal with extra info on derived types. */
+      if (BezierSpline *spline = dynamic_cast<BezierSpline *>(splines[i].get())) {
+        reverse_data<BezierSpline::HandleType>(spline->handle_types_left());
+        reverse_data<BezierSpline::HandleType>(spline->handle_types_right());
+        reverse_data<float3>(spline->handle_positions_left(), spline->handle_positions_right());
+      }
+      else if (NURBSpline *spline = dynamic_cast<NURBSpline *>(splines[i].get())) {
+        reverse_data<float>(spline->weights());
+      }
+      /* Nothing to do for poly splines. */
+
+      splines[i]->mark_cache_invalid();
+    }
+  });
+
+  params.set_output("Curve", geometry_set);
+}
+
+}  // namespace blender::nodes
+
+void register_node_type_geo_curve_reverse()
+{
+  static bNodeType ntype;
+  geo_node_type_base(&ntype, GEO_NODE_CURVE_REVERSE, "Curve Reverse", NODE_CLASS_GEOMETRY, 0);
+  node_type_socket_templates(&ntype, geo_node_curve_reverse_in, geo_node_curve_reverse_out);
+  ntype.geometry_node_execute = blender::nodes::geo_node_curve_reverse_exec;
+  nodeRegisterType(&ntype);
+}