Cleanup: refactoring uvislands to prepare for python api

Rename vert -> vertex.
Add `BM_uv_element_get_head`.

See also: D15598

5 files changed, 74 insertions, 98 deletions

diff --git a/source/blender/blenkernel/BKE_mesh_mapping.h b/source/blender/blenkernel/BKE_mesh_mapping.h
index 0c1839f9ac8..44588a06119 100644
--- a/source/blender/blenkernel/BKE_mesh_mapping.h
+++ b/source/blender/blenkernel/BKE_mesh_mapping.h
@@ -61,14 +61,16 @@ typedef struct UvElement {
  * the number of uvs per island.
  */
 typedef struct UvElementMap {
-  /* address UvElements by their vertex */
-  struct UvElement **vert;
   /** UvElement Storage. */
   struct UvElement *storage;
   /** Total number of UVs. */
   int total_uvs;
   /** Total number of unique UVs. */
   int total_unique_uvs;
+
+  /* If Non-NULL, address UvElements by `BM_elem_index_get(BMVert*)`. */
+  struct UvElement **vertex;
+
   /* Number of Islands in the mesh */
   int totalIslands;
   /* Stores the starting index in buf where each island begins */
diff --git a/source/blender/editors/include/ED_mesh.h b/source/blender/editors/include/ED_mesh.h
index 1981b069011..9d3fd5af47f 100644
--- a/source/blender/editors/include/ED_mesh.h
+++ b/source/blender/editors/include/ED_mesh.h
@@ -144,6 +144,7 @@ void BM_uv_element_map_free(struct UvElementMap *element_map);
 struct UvElement *BM_uv_element_get(struct UvElementMap *map,
                                     struct BMFace *efa,
                                     struct BMLoop *l);
+struct UvElement *BM_uv_element_get_head(struct UvElementMap *map, struct UvElement *child);
 
 /**
  * Can we edit UV's for this mesh?
diff --git a/source/blender/editors/mesh/editmesh_utils.c b/source/blender/editors/mesh/editmesh_utils.c
index 134532f0b21..78390db5349 100644
--- a/source/blender/editors/mesh/editmesh_utils.c
+++ b/source/blender/editors/mesh/editmesh_utils.c
@@ -732,25 +732,18 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
 
   BMVert *ev;
   BMFace *efa;
-  BMLoop *l;
   BMIter iter, liter;
-  /* vars from original func */
-  UvElementMap *element_map;
-  bool *winding = NULL;
   BLI_buffer_declare_static(vec2f, tf_uv_buf, BLI_BUFFER_NOP, BM_DEFAULT_NGON_STACK_SIZE);
-
   MLoopUV *luv;
-  int totverts, totfaces, i, totuv, j;
-
   const int cd_loop_uv_offset = CustomData_get_offset(&bm->ldata, CD_MLOOPUV);
+  if (cd_loop_uv_offset < 0) {
+    return NULL;
+  }
 
   BM_mesh_elem_index_ensure(bm, BM_VERT | BM_FACE);
 
-  totfaces = bm->totface;
-  totverts = bm->totvert;
-  totuv = 0;
-
-  /* generate UvElement array */
+  /* Count total uvs. */
+  int totuv = 0;
   BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) {
     if (BM_elem_flag_test(efa, BM_ELEM_HIDDEN)) {
       continue;
@@ -764,6 +757,7 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
       totuv += efa->len;
     }
     else {
+      BMLoop *l;
       BM_ITER_ELEM (l, &liter, efa, BM_LOOPS_OF_FACE) {
         if (uvedit_uv_select_test(scene, l, cd_loop_uv_offset)) {
           totuv++;
@@ -776,18 +770,17 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
     return NULL;
   }
 
-  element_map = (UvElementMap *)MEM_callocN(sizeof(*element_map), "UvElementMap");
+  UvElementMap *element_map = (UvElementMap *)MEM_callocN(sizeof(*element_map), "UvElementMap");
   element_map->total_uvs = totuv;
-  element_map->vert = (UvElement **)MEM_callocN(sizeof(*element_map->vert) * totverts,
-                                                "UvElementVerts");
+  element_map->vertex = (UvElement **)MEM_callocN(sizeof(*element_map->vertex) * bm->totvert,
+                                                  "UvElementVerts");
   element_map->storage = (UvElement *)MEM_callocN(sizeof(*element_map->storage) * totuv,
                                                   "UvElement");
 
-  if (use_winding) {
-    winding = MEM_callocN(sizeof(*winding) * totfaces, "winding");
-  }
+  bool *winding = use_winding ? MEM_callocN(sizeof(*winding) * bm->totface, "winding") : NULL;
 
   UvElement *buf = element_map->storage;
+  int j;
   BM_ITER_MESH_INDEX (efa, &iter, bm, BM_FACES_OF_MESH, j) {
 
     if (BM_elem_flag_test(efa, BM_ELEM_HIDDEN)) {
@@ -804,18 +797,20 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
       tf_uv = (float(*)[2])BLI_buffer_reinit_data(&tf_uv_buf, vec2f, efa->len);
     }
 
+    int i;
+    BMLoop *l;
     BM_ITER_ELEM_INDEX (l, &liter, efa, BM_LOOPS_OF_FACE, i) {
       if (uv_selected && !uvedit_uv_select_test(scene, l, cd_loop_uv_offset)) {
         continue;
       }
 
       buf->l = l;
-      buf->separate = 0;
       buf->island = INVALID_ISLAND;
       buf->loop_of_poly_index = i;
 
-      buf->next = element_map->vert[BM_elem_index_get(l->v)];
-      element_map->vert[BM_elem_index_get(l->v)] = buf;
+      /* Insert to head of linked list associated with BMVert. */
+      buf->next = element_map->vertex[BM_elem_index_get(l->v)];
+      element_map->vertex[BM_elem_index_get(l->v)] = buf;
 
       if (use_winding) {
         luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
@@ -830,34 +825,33 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
     }
   }
 
-  /* sort individual uvs for each vert */
+  /* For each BMVert, sort associated linked list into unique uvs. */
+  int i;
   BM_ITER_MESH_INDEX (ev, &iter, bm, BM_VERTS_OF_MESH, i) {
-    UvElement *newvlist = NULL, *vlist = element_map->vert[i];
-    UvElement *iterv, *v, *lastv, *next;
-    const float *uv, *uv2;
-    bool uv_vert_sel, uv2_vert_sel;
-
+    UvElement *newvlist = NULL;
+    UvElement *vlist = element_map->vertex[i];
     while (vlist) {
-      v = vlist;
+
+      /* Detach head from unsorted list. */
+      UvElement *v = vlist;
       vlist = vlist->next;
       v->next = newvlist;
-      newvlist = v;
+      UvElement *newvlist = v;
 
-      l = v->l;
-      luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
-      uv = luv->uv;
-      uv_vert_sel = uvedit_uv_select_test(scene, l, cd_loop_uv_offset);
+      luv = BM_ELEM_CD_GET_VOID_P(v->l, cd_loop_uv_offset);
+      const float *uv = luv->uv;
+      bool uv_vert_sel = uvedit_uv_select_test(scene, v->l, cd_loop_uv_offset);
 
-      lastv = NULL;
-      iterv = vlist;
+      UvElement *lastv = NULL;
+      UvElement *iterv = vlist;
 
+      /* Scan through unsorted list, finding UvElements which match `v`. */
       while (iterv) {
-        next = iterv->next;
+        UvElement *next = iterv->next;
 
-        l = iterv->l;
-        luv = BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset);
-        uv2 = luv->uv;
-        uv2_vert_sel = uvedit_uv_select_test(scene, l, cd_loop_uv_offset);
+        luv = BM_ELEM_CD_GET_VOID_P(iterv->l, cd_loop_uv_offset);
+        const float *uv2 = luv->uv;
+        const bool uv2_vert_sel = uvedit_uv_select_test(scene, iterv->l, cd_loop_uv_offset);
 
         /* Check if the uv loops share the same selection state (if not, they are not connected as
          * they have been ripped or other edit commands have separated them). */
@@ -886,18 +880,15 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
       newvlist->separate = true;
     }
 
-    element_map->vert[i] = newvlist;
+    /* Write back sorted list. */
+    element_map->vertex[i] = newvlist;
   }
 
-  if (use_winding) {
-    MEM_freeN(winding);
-  }
+  MEM_SAFE_FREE(winding);
 
   if (do_islands) {
     uint *map;
     UvElement *islandbuf;
-    /* island number for faces */
-    int *island_number = NULL;
 
     int nislands = 0, islandbufsize = 0;
 
@@ -905,8 +896,10 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
     map = MEM_mallocN(sizeof(*map) * totuv, "uvelement_remap");
     BMFace **stack = MEM_mallocN(sizeof(*stack) * bm->totface, "uv_island_face_stack");
     islandbuf = MEM_callocN(sizeof(*islandbuf) * totuv, "uvelement_island_buffer");
-    island_number = MEM_mallocN(sizeof(*island_number) * totfaces, "uv_island_number_face");
-    copy_vn_i(island_number, totfaces, INVALID_ISLAND);
+    /* Island number for BMFaces. */
+    int *island_number = MEM_callocN(sizeof(*island_number) * bm->totface,
+                                     "uv_island_number_face");
+    copy_vn_i(island_number, bm->totface, INVALID_ISLAND);
 
     const bool use_uv_edge_connectivity = scene->toolsettings->uv_flag & UV_SYNC_SELECTION ?
                                               scene->toolsettings->selectmode & SCE_SELECT_EDGE :
@@ -930,14 +923,15 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
         while (stacksize > 0) {
           efa = stack[--stacksize];
 
+          BMLoop *l;
           BM_ITER_ELEM (l, &liter, efa, BM_LOOPS_OF_FACE) {
             if (uv_selected && !uvedit_uv_select_test(scene, l, cd_loop_uv_offset)) {
               continue;
             }
 
-            UvElement *element, *initelement = element_map->vert[BM_elem_index_get(l->v)];
+            UvElement *initelement = element_map->vertex[BM_elem_index_get(l->v)];
 
-            for (element = initelement; element; element = element->next) {
+            for (UvElement *element = initelement; element; element = element->next) {
               if (element->separate) {
                 initelement = element;
               }
@@ -968,13 +962,13 @@ UvElementMap *BM_uv_element_map_create(BMesh *bm,
       }
     }
 
-    MEM_freeN(island_number);
+    MEM_SAFE_FREE(island_number);
 
     /* remap */
     for (i = 0; i < bm->totvert; i++) {
       /* important since we may do selection only. Some of these may be NULL */
-      if (element_map->vert[i]) {
-        element_map->vert[i] = &islandbuf[map[element_map->vert[i] - element_map->storage]];
+      if (element_map->vertex[i]) {
+        element_map->vertex[i] = &islandbuf[map[element_map->vertex[i] - element_map->storage]];
       }
     }
 
@@ -1032,24 +1026,35 @@ void BM_uv_vert_map_free(UvVertMap *vmap)
 void BM_uv_element_map_free(UvElementMap *element_map)
 {
   if (element_map) {
-    MEM_SAFE_FREE(element_map->vert);
     MEM_SAFE_FREE(element_map->storage);
+    MEM_SAFE_FREE(element_map->vertex);
     MEM_SAFE_FREE(element_map->islandIndices);
     MEM_SAFE_FREE(element_map);
   }
 }
 
-UvElement *BM_uv_element_get(UvElementMap *map, BMFace *efa, BMLoop *l)
+UvElement *BM_uv_element_get(UvElementMap *element_map, BMFace *efa, BMLoop *l)
 {
-  for (UvElement *element = map->vert[BM_elem_index_get(l->v)]; element; element = element->next) {
+  UvElement *element = element_map->vertex[BM_elem_index_get(l->v)];
+  while (element) {
     if (element->l->f == efa) {
       return element;
     }
+    element = element->next;
   }
 
   return NULL;
 }
 
+UvElement *BM_uv_element_get_head(UvElementMap *element_map, UvElement *child)
+{
+  if (!child) {
+    return NULL;
+  }
+
+  return element_map->vertex[BM_elem_index_get(child->l->v)];
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
diff --git a/source/blender/editors/sculpt_paint/sculpt_uv.c b/source/blender/editors/sculpt_paint/sculpt_uv.c
index a36b0fddeb6..f2017e68b4c 100644
--- a/source/blender/editors/sculpt_paint/sculpt_uv.c
+++ b/source/blender/editors/sculpt_paint/sculpt_uv.c
@@ -549,7 +549,7 @@ static UvSculptData *uv_sculpt_stroke_init(bContext *C, wmOperator *op, const wm
     int counter = -1;
     /* initialize the unique UVs */
     for (int i = 0; i < bm->totvert; i++) {
-      UvElement *element = data->elementMap->vert[i];
+      UvElement *element = data->elementMap->vertex[i];
       for (; element; element = element->next) {
         if (element->separate) {
           if (do_island_optimization && (element->island != island_index)) {
diff --git a/source/blender/editors/uvedit/uvedit_smart_stitch.c b/source/blender/editors/uvedit/uvedit_smart_stitch.c
index 854d3175979..26ed98ba236 100644
--- a/source/blender/editors/uvedit/uvedit_smart_stitch.c
+++ b/source/blender/editors/uvedit/uvedit_smart_stitch.c
@@ -569,22 +569,14 @@ static void stitch_island_calculate_vert_rotation(UvElement *element,
                                                   StitchState *state,
                                                   IslandStitchData *island_stitch_data)
 {
-  int index;
-  UvElement *element_iter;
   float rotation = 0, rotation_neg = 0;
   int rot_elem = 0, rot_elem_neg = 0;
-  BMLoop *l;
 
   if (element->island == ssc->static_island && !ssc->midpoints) {
     return;
   }
 
-  l = element->l;
-
-  index = BM_elem_index_get(l->v);
-
-  element_iter = state->element_map->vert[index];
-
+  UvElement *element_iter = BM_uv_element_get_head(state->element_map, element);
   for (; element_iter; element_iter = element_iter->next) {
     if (element_iter->separate &&
         stitch_check_uvs_state_stitchable(element, element_iter, ssc, state)) {
@@ -690,7 +682,7 @@ static void stitch_uv_edge_generate_linked_edges(GHash *edge_hash, StitchState *
       UvElement *element2 = state->uvs[edge->uv2];
 
       /* Now iterate through all faces and try to find edges sharing the same vertices */
-      UvElement *iter1 = element_map->vert[BM_elem_index_get(element1->l->v)];
+      UvElement *iter1 = BM_uv_element_get_head(state->element_map, element1);
       UvEdge *last_set = edge;
       int elemindex2 = BM_elem_index_get(element2->l->v);
 
@@ -758,15 +750,7 @@ static void determine_uv_stitchability(UvElement *element,
                                        StitchState *state,
                                        IslandStitchData *island_stitch_data)
 {
-  int vert_index;
-  UvElement *element_iter;
-  BMLoop *l;
-
-  l = element->l;
-
-  vert_index = BM_elem_index_get(l->v);
-  element_iter = state->element_map->vert[vert_index];
-
+  UvElement *element_iter = BM_uv_element_get_head(state->element_map, element);
   for (; element_iter; element_iter = element_iter->next) {
     if (element_iter->separate) {
       if (stitch_check_uvs_stitchable(element, element_iter, ssc, state)) {
@@ -847,16 +831,7 @@ static void stitch_validate_uv_stitchability(UvElement *element,
     return;
   }
 
-  UvElement *element_iter;
-  int vert_index;
-  BMLoop *l;
-
-  l = element->l;
-
-  vert_index = BM_elem_index_get(l->v);
-
-  element_iter = state->element_map->vert[vert_index];
-
+  UvElement *element_iter = BM_uv_element_get_head(state->element_map, element);
   for (; element_iter; element_iter = element_iter->next) {
     if (element_iter->separate) {
       if (element_iter == element) {
@@ -1273,7 +1248,6 @@ static int stitch_process_data(StitchStateContainer *ssc,
       if (element->flag & STITCH_STITCHABLE) {
         BMLoop *l;
         MLoopUV *luv;
-        UvElement *element_iter;
 
         l = element->l;
         luv = CustomData_bmesh_get(&bm->ldata, l->head.data, CD_MLOOPUV);
@@ -1287,8 +1261,7 @@ static int stitch_process_data(StitchStateContainer *ssc,
           continue;
         }
 
-        element_iter = state->element_map->vert[BM_elem_index_get(l->v)];
-
+        UvElement *element_iter = state->element_map->vertex[BM_elem_index_get(l->v)];
         for (; element_iter; element_iter = element_iter->next) {
           if (element_iter->separate) {
             if (stitch_check_uvs_state_stitchable(element, element_iter, ssc, state)) {
@@ -1585,13 +1558,8 @@ static void stitch_select_edge(UvEdge *edge, StitchState *state, int always_sele
 /* Select all common uvs */
 static void stitch_select_uv(UvElement *element, StitchState *state, int always_select)
 {
-  BMLoop *l;
-  UvElement *element_iter;
   UvElement **selection_stack = (UvElement **)state->selection_stack;
-
-  l = element->l;
-
-  element_iter = state->element_map->vert[BM_elem_index_get(l->v)];
+  UvElement *element_iter = BM_uv_element_get_head(state->element_map, element);
   /* first deselect all common uvs */
   for (; element_iter; element_iter = element_iter->next) {
     if (element_iter->separate) {
@@ -1934,7 +1902,7 @@ static StitchState *stitch_init(bContext *C,
   int counter = -1;
   /* initialize the unique UVs and map */
   for (int i = 0; i < em->bm->totvert; i++) {
-    UvElement *element = state->element_map->vert[i];
+    UvElement *element = state->element_map->vertex[i];
     for (; element; element = element->next) {
       if (element->separate) {
         counter++;