UV: path selection support

This adds support for path selection for vertex edge & face selection
modes, matching mesh editing behavior, useful with the UV rip tool.

Region select & edge tagging are currently not supported,
although they could be added eventually.

1 files changed, 63 insertions, 0 deletions

diff --git a/source/blender/editors/uvedit/uvedit_select.c b/source/blender/editors/uvedit/uvedit_select.c
index afc5739fcbd..a589114fd46 100644
--- a/source/blender/editors/uvedit/uvedit_select.c
+++ b/source/blender/editors/uvedit/uvedit_select.c
@@ -88,6 +88,59 @@ static void uv_select_tag_update_for_object(Depsgraph *depsgraph,
                                             Object *obedit);
 
 /* -------------------------------------------------------------------- */
+/** \name Active Selection Tracking
+ *
+ * Currently we don't store loops in the selection history,
+ * store face/edge/vert combinations (needed for UV path selection).
+ * \{ */
+
+void ED_uvedit_active_vert_loop_set(BMesh *bm, BMLoop *l)
+{
+  BM_select_history_clear(bm);
+  BM_select_history_remove(bm, (BMElem *)l->f);
+  BM_select_history_remove(bm, (BMElem *)l->v);
+  BM_select_history_store_notest(bm, (BMElem *)l->f);
+  BM_select_history_store_notest(bm, (BMElem *)l->v);
+}
+
+BMLoop *ED_uvedit_active_vert_loop_get(BMesh *bm)
+{
+  BMEditSelection *ese = bm->selected.last;
+  if (ese && ese->prev) {
+    BMEditSelection *ese_prev = ese->prev;
+    if ((ese->htype == BM_VERT) && (ese_prev->htype == BM_FACE)) {
+      /* May be NULL. */
+      return BM_face_vert_share_loop((BMFace *)ese_prev->ele, (BMVert *)ese->ele);
+    }
+  }
+  return NULL;
+}
+
+void ED_uvedit_active_edge_loop_set(BMesh *bm, BMLoop *l)
+{
+  BM_select_history_clear(bm);
+  BM_select_history_remove(bm, (BMElem *)l->f);
+  BM_select_history_remove(bm, (BMElem *)l->e);
+  BM_select_history_store_notest(bm, (BMElem *)l->f);
+  BM_select_history_store_notest(bm, (BMElem *)l->e);
+}
+
+BMLoop *ED_uvedit_active_edge_loop_get(BMesh *bm)
+{
+  BMEditSelection *ese = bm->selected.last;
+  if (ese && ese->prev) {
+    BMEditSelection *ese_prev = ese->prev;
+    if ((ese->htype == BM_EDGE) && (ese_prev->htype == BM_FACE)) {
+      /* May be NULL. */
+      return BM_face_edge_share_loop((BMFace *)ese_prev->ele, (BMEdge *)ese->ele);
+    }
+  }
+  return NULL;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
 /** \name Visibility and Selection Utilities
  * \{ */
 
@@ -1531,6 +1584,11 @@ static int uv_mouse_select_multi(bContext *C,
       hituv[hit.lindex] = hit.luv->uv;
 
       hitlen = hit.efa->len;
+
+      if ((ts->uv_flag & UV_SYNC_SELECTION) == 0) {
+        BMesh *bm = BKE_editmesh_from_object(hit.ob)->bm;
+        ED_uvedit_active_vert_loop_set(bm, hit.l);
+      }
     }
   }
   else if (selectmode == UV_SELECT_EDGE) {
@@ -1550,6 +1608,11 @@ static int uv_mouse_select_multi(bContext *C,
       hituv[(hit.lindex + 1) % hit.efa->len] = hit.luv_next->uv;
 
       hitlen = hit.efa->len;
+
+      if ((ts->uv_flag & UV_SYNC_SELECTION) == 0) {
+        BMesh *bm = BKE_editmesh_from_object(hit.ob)->bm;
+        ED_uvedit_active_edge_loop_set(bm, hit.l);
+      }
     }
   }
   else if (selectmode == UV_SELECT_FACE) {