Geometry Nodes: Curve Parameter Node

This commit adds a field input node that outputs the fraction of the
total length of the spline on each control point. This is useful for
anything that involves varying a value depending on how far along
the spline it is.

It also works when evaluated on the spline domain, where it outputs
the fraction of the total length of all of the splines at the start.

The operation isn't as well defined for NURB splines for the reasons
noted in the code comment. That can be said explicitly in the docs.

Differential Revision: https://developer.blender.org/D12548

2 files changed, 2 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_node.h b/source/blender/blenkernel/BKE_node.h
index e242aed879f..42e2cda8de3 100644
--- a/source/blender/blenkernel/BKE_node.h
+++ b/source/blender/blenkernel/BKE_node.h
@@ -1498,6 +1498,7 @@ int ntreeTexExecTree(struct bNodeTree *ntree,
 #define GEO_NODE_CURVE_SAMPLE 1085
 #define GEO_NODE_INPUT_TANGENT 1086
 #define GEO_NODE_STRING_JOIN 1087
+#define GEO_NODE_CURVE_PARAMETER 1088
 
 /** \} */
 
diff --git a/source/blender/blenkernel/intern/node.cc b/source/blender/blenkernel/intern/node.cc
index 7f423e53161..2d0239740f8 100644
--- a/source/blender/blenkernel/intern/node.cc
+++ b/source/blender/blenkernel/intern/node.cc
@@ -5187,6 +5187,7 @@ static void registerGeometryNodes()
   register_node_type_geo_curve_endpoints();
   register_node_type_geo_curve_fill();
   register_node_type_geo_curve_length();
+  register_node_type_geo_curve_parameter();
   register_node_type_geo_curve_primitive_bezier_segment();
   register_node_type_geo_curve_primitive_circle();
   register_node_type_geo_curve_primitive_line();