Match face tessellation order in edimode

add a negated version of axis_dominant_v3_to_m3

2 files changed, 20 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_math_geom.h b/source/blender/blenlib/BLI_math_geom.h
index 2c91aca27ef..359e2a97d9f 100644
--- a/source/blender/blenlib/BLI_math_geom.h
+++ b/source/blender/blenlib/BLI_math_geom.h
@@ -351,6 +351,7 @@ bool form_factor_visible_quad(const float p[3], const float n[3],
 float form_factor_hemi_poly(float p[3], float n[3],
                             float v1[3], float v2[3], float v3[3], float v4[3]);
 
+void axis_dominant_v3_to_m3_negate(float r_mat[3][3], const float normal[3]);
 void  axis_dominant_v3_to_m3(float r_mat[3][3], const float normal[3]);
 
 MINLINE void  axis_dominant_v3(int *r_axis_a, int *r_axis_b, const float axis[3]);
diff --git a/source/blender/blenlib/intern/math_geom.c b/source/blender/blenlib/intern/math_geom.c
index 7329a1177a8..f40f1cc3f97 100644
--- a/source/blender/blenlib/intern/math_geom.c
+++ b/source/blender/blenlib/intern/math_geom.c
@@ -2402,6 +2402,25 @@ void axis_dominant_v3_to_m3(float r_mat[3][3], const float normal[3])
 	BLI_assert((fabsf(dot_m3_v3_row_z(r_mat, normal) - 1.0f) < BLI_ASSERT_UNIT_EPSILON) || is_zero_v3(normal));
 }
 
+/**
+ * Same as axis_dominant_v3_to_m3, but flips the normal
+ */
+void axis_dominant_v3_to_m3_negate(float r_mat[3][3], const float normal[3])
+{
+	BLI_ASSERT_UNIT_V3(normal);
+
+	negate_v3_v3(r_mat[2], normal);
+	ortho_basis_v3v3_v3(r_mat[0], r_mat[1], r_mat[2]);
+
+	BLI_ASSERT_UNIT_V3(r_mat[0]);
+	BLI_ASSERT_UNIT_V3(r_mat[1]);
+
+	transpose_m3(r_mat);
+
+	BLI_assert(!is_negative_m3(r_mat));
+	BLI_assert((dot_m3_v3_row_z(r_mat, normal) < BLI_ASSERT_UNIT_EPSILON) || is_zero_v3(normal));
+}
+
 /****************************** Interpolation ********************************/
 
 static float tri_signed_area(const float v1[3], const float v2[3], const float v3[3], const int i, const int j)