Geometry Nodes: Curve to Points Node for Evaluated Data

This node implements the second option of T87429, creating points
along the input splines with the necessary evaluated information
for instancing: `tangent`, `normal`, and `rotation` attributes.
All generic curve point and spline attributes are copied to the
result points as well.

The "Count" and "Length" methods are just like the current options
in the resample node, but the output is points instead of a curve.
The "Evaluated" method uses the points you see on the curve directly,
and therefore should be the fastest.

The rotation data is retrieved from a transform matrix built with the
same method that the curve to mesh node uses. The radius attribute is
divided by 10 so the points don't look absurdly huge in the viewport.
In the future that could be an option.

For the implementation, one thing that could use an improvement
is the amount of temporary allocations while resampling to evaluated
points before the final points. I expect that reusing a buffer for
each thread would give a nice improvement.

Differential Revision: https://developer.blender.org/D11539

1 files changed, 32 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 7271ecb49eb..87bfb554611 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -9849,6 +9849,38 @@ static void def_geo_curve_resample(StructRNA *srna)
   RNA_def_property_update(prop, NC_NODE | NA_EDITED, "rna_Node_socket_update");
 }
 
+static void def_geo_curve_to_points(StructRNA *srna)
+{
+  PropertyRNA *prop;
+
+  static EnumPropertyItem mode_items[] = {
+      {GEO_NODE_CURVE_SAMPLE_EVALUATED,
+       "EVALUATED",
+       0,
+       "Evaluated",
+       "Create points from the curve's evaluated points, based on the resolution attribute for "
+       "NURBS and Bezier splines"},
+      {GEO_NODE_CURVE_SAMPLE_COUNT,
+       "COUNT",
+       0,
+       "Count",
+       "Sample each spline by evenly distributing the specified number of points"},
+      {GEO_NODE_CURVE_SAMPLE_LENGTH,
+       "LENGTH",
+       0,
+       "Length",
+       "Sample each spline by splitting it into segments with the specified length"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
+  RNA_def_struct_sdna_from(srna, "NodeGeometryCurveToPoints", "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 generate points from the input curve");
+  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[] = {