1 files changed, 39 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/math_vector.c b/source/blender/blenlib/intern/math_vector.c
index 812e2b3e63d..490ed2a99fb 100644
--- a/source/blender/blenlib/intern/math_vector.c
+++ b/source/blender/blenlib/intern/math_vector.c
@@ -122,6 +122,32 @@ void mid_v3_v3v3v3(float v[3], const float v1[3], const float v2[3], const float
 	v[2] = (v1[2] + v2[2] + v3[2]) / 3.0f;
 }
 
+/**
+ * Equivalent to:
+ * interp_v3_v3v3(v, v1, v2, -1.0f);
+ */
+
+void flip_v4_v4v4(float v[4], const float v1[4], const float v2[4])
+{
+	v[0] = v1[0] + (v1[0] - v2[0]);
+	v[1] = v1[1] + (v1[1] - v2[1]);
+	v[2] = v1[2] + (v1[2] - v2[2]);
+	v[3] = v1[3] + (v1[3] - v2[3]);
+}
+
+void flip_v3_v3v3(float v[3], const float v1[3], const float v2[3])
+{
+	v[0] = v1[0] + (v1[0] - v2[0]);
+	v[1] = v1[1] + (v1[1] - v2[1]);
+	v[2] = v1[2] + (v1[2] - v2[2]);
+}
+
+void flip_v2_v2v2(float v[2], const float v1[2], const float v2[2])
+{
+	v[0] = v1[0] + (v1[0] - v2[0]);
+	v[1] = v1[1] + (v1[1] - v2[1]);
+}
+
 /********************************** Angles ***********************************/
 
 /* Return the angle in radians between vecs 1-2 and 2-3 in radians
@@ -685,6 +711,19 @@ void msub_vn_vnvn(float *array_tar, const float *array_src_a, const float *array
 	}
 }
 
+void interp_vn_vn(float *array_tar, const float *array_src, const float t, const int size)
+{
+	const float s = 1.0f - t;
+	float *tar = array_tar + (size - 1);
+	const float *src = array_src + (size - 1);
+	int i = size;
+	while (i--) {
+		*(tar) = (s * *(tar)) + (t * *(src));
+		tar--;
+		src--;
+	}
+}
+
 void fill_vn_i(int *array_tar, const int size, const int val)
 {
 	int *tar = array_tar + (size - 1);