mathutils py api:

  Vector.angle_signed(other)
  for 2D vectors to get the clockwise angle between them.

  in BLI math its called - angle_signed_v2v2()

shorthand for...

  atan2f((v1[1] * v2[0]) - (v1[0] * v2[1]), dot_v2v2(v1, v2))

also corrects compile error in last commit.

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_math_vector.h b/source/blender/blenlib/BLI_math_vector.h
index 1a24acfe1a5..b8b53f1ba7c 100644
--- a/source/blender/blenlib/BLI_math_vector.h
+++ b/source/blender/blenlib/BLI_math_vector.h
@@ -176,6 +176,7 @@ MINLINE float line_point_side_v2(const float l1[2], const float l2[2], const flo
 /* - angle_normalized_* is faster equivalent if vectors are normalized       */
 
 float angle_v2v2(const float a[2], const float b[2]);
+float angle_signed_v2v2(const float v1[2], const float v2[2]);
 float angle_v2v2v2(const float a[2], const float b[2], const float c[2]);
 float angle_normalized_v2v2(const float a[2], const float b[2]);
 float angle_v3v3(const float a[3], const float b[3]);