Fix related to new split normals draw code.

Tessellated split normals CDlayer had no swap func, hence ugly little test_index_face()
could not rotate its values correctly when rotating tessellated faces...

Extra-reported in T39735.

2 files changed, 15 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/customdata.c b/source/blender/blenkernel/intern/customdata.c
index 0309e7defbe..4a76abc0154 100644
--- a/source/blender/blenkernel/intern/customdata.c
+++ b/source/blender/blenkernel/intern/customdata.c
@@ -1070,6 +1070,19 @@ static void layerInterp_mvert_skin(void **sources, const float *weights,
 	vs->flag &= ~MVERT_SKIN_ROOT;
 }
 
+static void layerSwap_flnor(void *data, const int *corner_indices)
+{
+	short (*flnors)[4][3] = data;
+	short nors[4][3];
+	int i = 4;
+
+	while (i--) {
+		copy_v3_v3_short(nors[i], (*flnors)[corner_indices[i]]);
+	}
+
+	memcpy(flnors, nors, sizeof(nors));
+}
+
 static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
 	/* 0: CD_MVERT */
 	{sizeof(MVert), "MVert", 1, NULL, NULL, NULL, NULL, NULL, NULL},
@@ -1182,7 +1195,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
 	/* 39: CD_MLOOPTANGENT */
 	{sizeof(float[4]), "", 0, NULL, NULL, NULL, NULL, NULL, NULL},
 	/* 40: CD_TESSLOOPNORMAL */
-	{sizeof(short[4][3]), "", 0, NULL, NULL, NULL, NULL, NULL, NULL},
+	{sizeof(short[4][3]), "", 0, NULL, NULL, NULL, NULL, layerSwap_flnor, NULL},
     /* 41: CD_DYNTOPO_NODE */
 	{sizeof(int), "", 0, NULL, NULL, NULL, NULL, NULL, layerDefault_dyntopo_node},
 };
diff --git a/source/blender/blenkernel/intern/mesh_evaluate.c b/source/blender/blenkernel/intern/mesh_evaluate.c
index fe37b9222b6..281e98e7b05 100644
--- a/source/blender/blenkernel/intern/mesh_evaluate.c
+++ b/source/blender/blenkernel/intern/mesh_evaluate.c
@@ -1236,7 +1236,7 @@ void BKE_mesh_loops_to_tessdata(CustomData *fdata, CustomData *ldata, CustomData
 		float (*lnors)[3] = CustomData_get_layer(ldata, CD_NORMAL);
 
 		for (findex = 0, lidx = loopindices; findex < num_faces; lidx++, findex++, fnors++) {
-			for (j = (*lidx)[3] ? 4 : 3; j--;) {
+			for (j = (mface ? mface[findex].v4 : (*lidx)[3]) ? 4 : 3; j--;) {
 				normal_float_to_short_v3((*fnors)[j], lnors[(*lidx)[j]]);
 			}
 		}