Math Lib: redundant axis flip decomposing a plane

Also add a faster, non-normalized version of the function.

(Neither are used currently used).

2 files changed, 15 insertions, 5 deletions

diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h
index 9023cdd17bf..4f7a3310ee6 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -74,7 +74,9 @@ float cross_poly_v2(const float verts[][2], unsigned int nr);
 /********************************* Planes **********************************/
 
 void  plane_from_point_normal_v3(float r_plane[4], const float plane_co[3], const float plane_no[3]);
-void  plane_to_point_normal_v3(const float plane[4], float r_plane_co[3], float r_plane_no[3]);
+void  plane_to_point_vector_v3(const float plane[4], float r_plane_co[3], float r_plane_no[3]);
+void  plane_to_point_vector_v3_normalized(const float plane[4], float r_plane_co[3], float r_plane_no[3]);
+
 MINLINE float plane_point_side_v3(const float plane[4], const float co[3]);
 
 /********************************* Volume **********************************/
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index eee78297106..ba1f4480659 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -257,14 +257,22 @@ void plane_from_point_normal_v3(float r_plane[4], const float plane_co[3], const
 }
 
 /**
- * Get a point and a normal from a plane.
+ * Get a point and a direction from a plane.
  */
-void plane_to_point_normal_v3(const float plane[4], float r_plane_co[3], float r_plane_no[3])
+void plane_to_point_vector_v3(const float plane[4], float r_plane_co[3], float r_plane_no[3])
 {
-	const float length = normalize_v3_v3(r_plane_no, plane);
-	madd_v3_v3v3fl(r_plane_co, r_plane_no, r_plane_no, (-plane[3] / length) - 1.0f);
+	mul_v3_v3fl(r_plane_co, plane, (-plane[3] / len_squared_v3(plane)));
+	copy_v3_v3(r_plane_no, plane);
 }
 
+/**
+ * version of #plane_to_point_vector_v3 that gets a unit length vector.
+ */
+void plane_to_point_vector_v3_normalized(const float plane[4], float r_plane_co[3], float r_plane_no[3])
+{
+	const float length = normalize_v3_v3(r_plane_no, plane);
+	mul_v3_v3fl(r_plane_co, r_plane_no, (-plane[3] / length));
+}
 
 /********************************* Volume **********************************/