Transform: UV islands were split by winding

This meant front/back faces from a projection would be seen as separate islands.

5 files changed, 35 insertions, 17 deletions

diff --git a/source/blender/editors/include/ED_mesh.h b/source/blender/editors/include/ED_mesh.h
index 3f16055e762..9534da622fb 100644
--- a/source/blender/editors/include/ED_mesh.h
+++ b/source/blender/editors/include/ED_mesh.h
@@ -107,7 +107,9 @@ void EDBM_mesh_reveal(struct BMEditMesh *em);
 
 void EDBM_update_generic(struct BMEditMesh *em, const bool do_tessface, const bool is_destructive);
 
-struct UvElementMap *BM_uv_element_map_create(struct BMesh *bm, const bool selected, const bool do_islands);
+struct UvElementMap *BM_uv_element_map_create(
+        struct BMesh *bm,
+        const bool selected, const bool use_winding, const bool do_islands);
 void                 BM_uv_element_map_free(struct UvElementMap *vmap);
 struct UvElement    *BM_uv_element_get(struct UvElementMap *map, struct BMFace *efa, struct BMLoop *l);
 
diff --git a/source/blender/editors/mesh/editmesh_utils.c b/source/blender/editors/mesh/editmesh_utils.c
index 2e43c9b0be8..d521b2c01e5 100644
--- a/source/blender/editors/mesh/editmesh_utils.c
+++ b/source/blender/editors/mesh/editmesh_utils.c
@@ -768,7 +768,9 @@ UvMapVert *BM_uv_vert_map_at_index(UvVertMap *vmap, unsigned int v)
 
 
 /* A specialized vert map used by stitch operator */
-UvElementMap *BM_uv_element_map_create(BMesh *bm, const bool selected, const bool do_islands)
+UvElementMap *BM_uv_element_map_create(
+        BMesh *bm,
+        const bool selected, const bool use_winding, const bool do_islands)
 {
 	BMVert *ev;
 	BMFace *efa;
@@ -807,14 +809,22 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm, const bool selected, const boo
 	element_map->vert = (UvElement **)MEM_callocN(sizeof(*element_map->vert) * totverts, "UvElementVerts");
 	buf = element_map->buf = (UvElement *)MEM_callocN(sizeof(*element_map->buf) * totuv, "UvElement");
 
-	winding = MEM_mallocN(sizeof(*winding) * totfaces, "winding");
+	if (use_winding) {
+		winding = MEM_mallocN(sizeof(*winding) * totfaces, "winding");
+	}
 
 	BM_ITER_MESH_INDEX (efa, &iter, bm, BM_FACES_OF_MESH, j) {
 
-		winding[j] = false;
+		if (use_winding) {
+			winding[j] = false;
+		}
 
 		if (!selected || BM_elem_flag_test(efa, BM_ELEM_SELECT)) {
-			float (*tf_uv)[2]     = (float (*)[2])BLI_buffer_resize_data(&tf_uv_buf, vec2f, efa->len);
+			float (*tf_uv)[2];
+
+			if (use_winding) {
+				tf_uv = (float (*)[2])BLI_buffer_resize_data(&tf_uv_buf, vec2f, efa->len);
+			}
 
 			BM_ITER_ELEM_INDEX (l, &liter, efa, BM_LOOPS_OF_FACE, i) {
 				buf->l = l;
@@ -825,13 +835,17 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm, const bool selected, const boo
 				buf->next = element_map->vert[BM_elem_index_get(l->v)];
 				element_map->vert[BM_elem_index_get(l->v)] = buf;
 
-				luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
-				copy_v2_v2(tf_uv[i], luv->uv);
+				if (use_winding) {
+					luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
+					copy_v2_v2(tf_uv[i], luv->uv);
+				}
 
 				buf++;
 			}
 
-			winding[j] = cross_poly_v2((const float (*)[2])tf_uv, efa->len) > 0;
+			if (use_winding) {
+				winding[j] = cross_poly_v2((const float (*)[2])tf_uv, efa->len) > 0;
+			}
 		}
 	}
 
@@ -864,7 +878,7 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm, const bool selected, const boo
 				sub_v2_v2v2(uvdiff, uv2, uv);
 
 				if (fabsf(uvdiff[0]) < STD_UV_CONNECT_LIMIT && fabsf(uvdiff[1]) < STD_UV_CONNECT_LIMIT &&
-				    winding[BM_elem_index_get(iterv->l->f)] == winding[BM_elem_index_get(v->l->f)])
+				    (!use_winding || winding[BM_elem_index_get(iterv->l->f)] == winding[BM_elem_index_get(v->l->f)]))
 				{
 					if (lastv) lastv->next = next;
 					else vlist = next;
@@ -884,7 +898,9 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm, const bool selected, const boo
 		element_map->vert[i] = newvlist;
 	}
 
-	MEM_freeN(winding);
+	if (use_winding) {
+		MEM_freeN(winding);
+	}
 
 	if (do_islands) {
 		unsigned int *map;
diff --git a/source/blender/editors/sculpt_paint/sculpt_uv.c b/source/blender/editors/sculpt_paint/sculpt_uv.c
index 4e1517b4e0d..03ca38f2df7 100644
--- a/source/blender/editors/sculpt_paint/sculpt_uv.c
+++ b/source/blender/editors/sculpt_paint/sculpt_uv.c
@@ -612,18 +612,18 @@ static UvSculptData *uv_sculpt_stroke_init(bContext *C, wmOperator *op, const wm
 		if (do_island_optimization) {
 			/* We will need island information */
 			if (ts->uv_flag & UV_SYNC_SELECTION) {
-				data->elementMap = BM_uv_element_map_create(bm, false, true);
+				data->elementMap = BM_uv_element_map_create(bm, false, true, true);
 			}
 			else {
-				data->elementMap = BM_uv_element_map_create(bm, true, true);
+				data->elementMap = BM_uv_element_map_create(bm, true, true, true);
 			}
 		}
 		else {
 			if (ts->uv_flag & UV_SYNC_SELECTION) {
-				data->elementMap = BM_uv_element_map_create(bm, false, false);
+				data->elementMap = BM_uv_element_map_create(bm, false, false, true);
 			}
 			else {
-				data->elementMap = BM_uv_element_map_create(bm, true, false);
+				data->elementMap = BM_uv_element_map_create(bm, true, false, true);
 			}
 		}
 
diff --git a/source/blender/editors/transform/transform_conversions.c b/source/blender/editors/transform/transform_conversions.c
index bcd69538b44..abaa55e3e9c 100644
--- a/source/blender/editors/transform/transform_conversions.c
+++ b/source/blender/editors/transform/transform_conversions.c
@@ -2741,7 +2741,7 @@ static void createTransUVs(bContext *C, TransInfo *t)
 	if (is_prop_connected || is_island_center) {
 		/* create element map with island information */
 		const bool use_facesel = (ts->uv_flag & UV_SYNC_SELECTION) == 0;
-		elementmap = BM_uv_element_map_create(em->bm, use_facesel, true);
+		elementmap = BM_uv_element_map_create(em->bm, use_facesel, false, true);
 		if (elementmap == NULL) {
 			return;
 		}
diff --git a/source/blender/editors/uvedit/uvedit_smart_stitch.c b/source/blender/editors/uvedit/uvedit_smart_stitch.c
index f7a8735ccca..828537fd585 100644
--- a/source/blender/editors/uvedit/uvedit_smart_stitch.c
+++ b/source/blender/editors/uvedit/uvedit_smart_stitch.c
@@ -1649,10 +1649,10 @@ static int stitch_init(bContext *C, wmOperator *op)
 
 	/* in uv synch selection, all uv's are visible */
 	if (ts->uv_flag & UV_SYNC_SELECTION) {
-		state->element_map = BM_uv_element_map_create(state->em->bm, false, true);
+		state->element_map = BM_uv_element_map_create(state->em->bm, false, true, true);
 	}
 	else {
-		state->element_map = BM_uv_element_map_create(state->em->bm, true, true);
+		state->element_map = BM_uv_element_map_create(state->em->bm, true, true, true);
 	}
 	if (!state->element_map) {
 		state_delete(state);