Geometry Nodes: Curve Trim Node

This node implements shortening each spline in the curve based on
either a length from the start of each spline, or a factor of the
total length of each spline, similar to the "Start & End Mapping"
panel of curve properties.

For Bezier curves, the first and last control points are adjusted
to maintain the shape of the curve, but NURB splines are currently
implicitly converted to poly splines.

The node is implemented to avoid copying where possible, so it outputs
a changed version of the input curve rather than a new one.

Differential Revision: https://developer.blender.org/D11901

1 files changed, 26 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 4712f4a0a0b..6998a7d0afe 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -10039,6 +10039,32 @@ static void def_geo_curve_to_points(StructRNA *srna)
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
 }
 
+static void def_geo_curve_trim(StructRNA *srna)
+{
+  PropertyRNA *prop;
+
+  static EnumPropertyItem mode_items[] = {
+      {GEO_NODE_CURVE_INTERPOLATE_FACTOR,
+       "FACTOR",
+       0,
+       "Factor",
+       "Find the endpoint positions using a factor of each spline's length"},
+      {GEO_NODE_CURVE_INTERPOLATE_LENGTH,
+       "LENGTH",
+       0,
+       "Length",
+       "Find the endpoint positions using a length from the start of each spline"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  RNA_def_struct_sdna_from(srna, "NodeGeometryCurveTrim", "storage");
+
+  prop = RNA_def_property(srna, "mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, mode_items);
+  RNA_def_property_ui_text(prop, "Mode", "How to find endpoint positions for the trimmed spline");
+  RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
+}
+
 static void def_geo_attribute_transfer(StructRNA *srna)
 {
   static EnumPropertyItem mapping_items[] = {