Match face tessellation order in edimode

add a negated version of axis_dominant_v3_to_m3

4 files changed, 28 insertions, 8 deletions

diff --git a/source/blender/blenkernel/intern/mesh_evaluate.c b/source/blender/blenkernel/intern/mesh_evaluate.c
index 00a82727e59..40a299ef343 100644
--- a/source/blender/blenkernel/intern/mesh_evaluate.c
+++ b/source/blender/blenkernel/intern/mesh_evaluate.c
@@ -2420,7 +2420,7 @@ int BKE_mesh_recalc_tessellation(
 			co_prev = mvert[ml[mp_totloop - 1].v].co;
 			for (j = 0; j < mp_totloop; j++, ml++) {
 				co_curr = mvert[ml->v].co;
-				add_newell_cross_v3_v3v3(normal, co_curr, co_prev);
+				add_newell_cross_v3_v3v3(normal, co_prev, co_curr);
 				co_prev = co_curr;
 			}
 			if (UNLIKELY(normalize_v3(normal) == 0.0f)) {
@@ -2428,7 +2428,7 @@ int BKE_mesh_recalc_tessellation(
 			}
 
 			/* project verts to 2d */
-			axis_dominant_v3_to_m3(axis_mat, normal);
+			axis_dominant_v3_to_m3_negate(axis_mat, normal);
 
 			ml = mloop + mp_loopstart;
 			for (j = 0; j < mp_totloop; j++, ml++) {
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)
diff --git a/source/blender/bmesh/intern/bmesh_polygon.c b/source/blender/bmesh/intern/bmesh_polygon.c
index d2d31d6a562..1318ad0f7fa 100644
--- a/source/blender/bmesh/intern/bmesh_polygon.c
+++ b/source/blender/bmesh/intern/bmesh_polygon.c
@@ -856,14 +856,14 @@ void BM_face_triangulate(
 		const int last_tri = f->len - 3;
 		int i;
 
-		axis_dominant_v3_to_m3(axis_mat, f->no);
+		axis_dominant_v3_to_m3_negate(axis_mat, f->no);
 
 		for (i = 0, l_iter = BM_FACE_FIRST_LOOP(f); i < f->len; i++, l_iter = l_iter->next) {
 			loops[i] = l_iter;
 			mul_v2_m3v3(projverts[i], axis_mat, l_iter->v->co);
 		}
 
-		BLI_polyfill_calc_arena((const float (*)[2])projverts, f->len, -1, tris,
+		BLI_polyfill_calc_arena((const float (*)[2])projverts, f->len, 1, tris,
 		                        pf_arena);
 
 		if (use_beauty) {
@@ -1259,7 +1259,7 @@ void BM_bmesh_calc_tessellation(BMesh *bm, BMLoop *(*looptris)[3], int *r_looptr
 			l_arr = BLI_memarena_alloc(arena, sizeof(*l_arr) * efa->len);
 			projverts = BLI_memarena_alloc(arena, sizeof(*projverts) * efa->len);
 
-			axis_dominant_v3_to_m3(axis_mat, efa->no);
+			axis_dominant_v3_to_m3_negate(axis_mat, efa->no);
 
 			j = 0;
 			l_iter = l_first = BM_FACE_FIRST_LOOP(efa);
@@ -1269,15 +1269,15 @@ void BM_bmesh_calc_tessellation(BMesh *bm, BMLoop *(*looptris)[3], int *r_looptr
 				j++;
 			} while ((l_iter = l_iter->next) != l_first);
 
-			BLI_polyfill_calc_arena((const float (*)[2])projverts, efa->len, -1, tris, arena);
+			BLI_polyfill_calc_arena((const float (*)[2])projverts, efa->len, 1, tris, arena);
 
 			for (j = 0; j < totfilltri; j++) {
 				BMLoop **l_ptr = looptris[i++];
 				unsigned int *tri = tris[j];
 
-				l_ptr[0] = l_arr[tri[2]];
+				l_ptr[0] = l_arr[tri[0]];
 				l_ptr[1] = l_arr[tri[1]];
-				l_ptr[2] = l_arr[tri[0]];
+				l_ptr[2] = l_arr[tri[2]];
 			}
 
 			BLI_memarena_clear(arena);