Curves: Port fillet node to the new data-block

This commit ports the fillet curves node to the new curves data-block,
and moves the fillet node implementation to the geometry module to help
separate the implementation from the node.

The changes are similar to the subdivide node or resample node. I've
resused common utilities where it makes sense, though some things like
the iteration over attributes can be generalized further. The node
is now multi-threaded per-curve and inside each curve, and some buffers
are reused per curve to avoid many allocations.

The code is more explicit now, and though there is more boilerplate to
pass around many spans, the more complex logic should be more readable.

Differential Revision: https://developer.blender.org/D15346

1 files changed, 9 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_math_rotation.hh b/source/blender/blenlib/BLI_math_rotation.hh
index e8b746b34df..50a062162ad 100644
--- a/source/blender/blenlib/BLI_math_rotation.hh
+++ b/source/blender/blenlib/BLI_math_rotation.hh
@@ -15,4 +15,13 @@ namespace blender::math {
  */
 float3 rotate_direction_around_axis(const float3 &direction, const float3 &axis, float angle);
 
+/**
+ * Rotate any arbitrary \a vector around the \a center position, with a unit-length \a axis
+ * and the specified \a angle.
+ */
+float3 rotate_around_axis(const float3 &vector,
+                          const float3 &center,
+                          const float3 &axis,
+                          float angle);
+
 }  // namespace blender::math