Cleanup: refactoring uvislands to prepare for python api

Add element_map->island_total_uvs.
Add element_map->island_total_unique_uvs.
Simplify callers based on new members.
Add comments.

Resolves: D15598

6 files changed, 44 insertions, 59 deletions

diff --git a/source/blender/editors/mesh/editmesh_utils.c b/source/blender/editors/mesh/editmesh_utils.c
index a0e20e4db8a..e931dd02a9e 100644
--- a/source/blender/editors/mesh/editmesh_utils.c
+++ b/source/blender/editors/mesh/editmesh_utils.c
@@ -820,28 +820,32 @@ static void bm_uv_build_islands(UvElementMap *element_map,
     }
   }
 
-  element_map->islandIndices = MEM_callocN(sizeof(*element_map->islandIndices) * nislands,
-                                           "UvElementMap_island_indices");
+  element_map->island_indices = MEM_callocN(sizeof(*element_map->island_indices) * nislands,
+                                            __func__);
+  element_map->island_total_uvs = MEM_callocN(sizeof(*element_map->island_total_uvs) * nislands,
+                                              __func__);
+  element_map->island_total_unique_uvs = MEM_callocN(
+      sizeof(*element_map->island_total_unique_uvs) * nislands, __func__);
   int j = 0;
   for (int i = 0; i < totuv; i++) {
-    UvElement *element = element_map->storage[i].next;
-    if (element == NULL) {
-      islandbuf[map[i]].next = NULL;
-    }
-    else {
-      islandbuf[map[i]].next = &islandbuf[map[element - element_map->storage]];
-    }
+    UvElement *next = element_map->storage[i].next;
+    islandbuf[map[i]].next = next ? &islandbuf[map[next - element_map->storage]] : NULL;
 
     if (islandbuf[i].island != j) {
       j++;
-      element_map->islandIndices[j] = i;
+      element_map->island_indices[j] = i;
+    }
+    BLI_assert(islandbuf[i].island == j);
+    element_map->island_total_uvs[j]++;
+    if (islandbuf[i].separate) {
+      element_map->island_total_unique_uvs[j]++;
     }
   }
 
   MEM_SAFE_FREE(element_map->storage);
   element_map->storage = islandbuf;
   islandbuf = NULL;
-  element_map->totalIslands = nislands;
+  element_map->total_islands = nislands;
   MEM_SAFE_FREE(stack);
   MEM_SAFE_FREE(map);
 }
@@ -1059,7 +1063,9 @@ void BM_uv_element_map_free(UvElementMap *element_map)
     MEM_SAFE_FREE(element_map->storage);
     MEM_SAFE_FREE(element_map->vertex);
     MEM_SAFE_FREE(element_map->head_table);
-    MEM_SAFE_FREE(element_map->islandIndices);
+    MEM_SAFE_FREE(element_map->island_indices);
+    MEM_SAFE_FREE(element_map->island_total_uvs);
+    MEM_SAFE_FREE(element_map->island_total_unique_uvs);
     MEM_SAFE_FREE(element_map);
   }
 }
diff --git a/source/blender/editors/sculpt_paint/sculpt_uv.c b/source/blender/editors/sculpt_paint/sculpt_uv.c
index 2e2abd30ea2..14b06f888fe 100644
--- a/source/blender/editors/sculpt_paint/sculpt_uv.c
+++ b/source/blender/editors/sculpt_paint/sculpt_uv.c
@@ -518,13 +518,7 @@ static UvSculptData *uv_sculpt_stroke_init(bContext *C, wmOperator *op, const wm
     /* Count 'unique' UV's */
     int unique_uvs = data->elementMap->total_unique_uvs;
     if (do_island_optimization) {
-      unique_uvs = 0;
-      for (int i = 0; i < data->elementMap->total_uvs; i++) {
-        if (data->elementMap->storage[i].separate &&
-            (data->elementMap->storage[i].island == island_index)) {
-          unique_uvs++;
-        }
-      }
+      unique_uvs = data->elementMap->island_total_unique_uvs[island_index];
     }
 
     /* Allocate the unique uv buffers */
@@ -572,6 +566,7 @@ static UvSculptData *uv_sculpt_stroke_init(bContext *C, wmOperator *op, const wm
         uniqueUv[element - data->elementMap->storage] = counter;
       }
     }
+    BLI_assert(counter + 1 == unique_uvs);
 
     /* Now, on to generate our uv connectivity data */
     counter = 0;
diff --git a/source/blender/editors/transform/transform_convert_mesh_uv.c b/source/blender/editors/transform/transform_convert_mesh_uv.c
index d95bc7b976f..f3bef2c283b 100644
--- a/source/blender/editors/transform/transform_convert_mesh_uv.c
+++ b/source/blender/editors/transform/transform_convert_mesh_uv.c
@@ -270,7 +270,7 @@ static void createTransUVs(bContext *C, TransInfo *t)
         continue;
       }
 
-      island_center = MEM_callocN(sizeof(*island_center) * elementmap->totalIslands, __func__);
+      island_center = MEM_callocN(sizeof(*island_center) * elementmap->total_islands, __func__);
     }
 
     BM_ITER_MESH (efa, &iter, em->bm, BM_FACES_OF_MESH) {
@@ -315,9 +315,7 @@ static void createTransUVs(bContext *C, TransInfo *t)
     }
 
     if (is_island_center) {
-      int i;
-
-      for (i = 0; i < elementmap->totalIslands; i++) {
+      for (int i = 0; i < elementmap->total_islands; i++) {
         mul_v2_fl(island_center[i].co, 1.0f / island_center[i].co_num);
         mul_v2_v2(island_center[i].co, t->aspect);
       }
diff --git a/source/blender/editors/uvedit/uvedit_ops.c b/source/blender/editors/uvedit/uvedit_ops.c
index 092f0c49d8a..6755630d3ef 100644
--- a/source/blender/editors/uvedit/uvedit_ops.c
+++ b/source/blender/editors/uvedit/uvedit_ops.c
@@ -541,14 +541,11 @@ static bool uvedit_uv_straighten(Scene *scene, BMesh *bm, eUVWeldAlign tool)
   }
 
   bool changed = false;
-
-  /* Loop backwards to simplify logic. */
-  int j1 = element_map->total_uvs;
-  for (int i = element_map->totalIslands - 1; i >= 0; --i) {
-    int j0 = element_map->islandIndices[i];
-    changed |= uvedit_uv_straighten_elements(
-        element_map->storage + j0, j1 - j0, cd_loop_uv_offset, tool);
-    j1 = j0;
+  for (int i = 0; i < element_map->total_islands; i++) {
+    changed |= uvedit_uv_straighten_elements(element_map->storage + element_map->island_indices[i],
+                                             element_map->island_total_uvs[i],
+                                             cd_loop_uv_offset,
+                                             tool);
   }
 
   BM_uv_element_map_free(element_map);
diff --git a/source/blender/editors/uvedit/uvedit_select.c b/source/blender/editors/uvedit/uvedit_select.c
index 749c59ea6a4..d88da21ef98 100644
--- a/source/blender/editors/uvedit/uvedit_select.c
+++ b/source/blender/editors/uvedit/uvedit_select.c
@@ -5395,7 +5395,7 @@ static void uv_isolate_selected_islands(const Scene *scene,
     return;
   }
 
-  int num_islands = elementmap->totalIslands;
+  int num_islands = elementmap->total_islands;
   /* Boolean array that tells if island with index i is completely selected or not. */
   bool *is_island_not_selected = MEM_callocN(sizeof(bool) * (num_islands), __func__);
 
diff --git a/source/blender/editors/uvedit/uvedit_smart_stitch.c b/source/blender/editors/uvedit/uvedit_smart_stitch.c
index 26ed98ba236..4a2ea5c3aa6 100644
--- a/source/blender/editors/uvedit/uvedit_smart_stitch.c
+++ b/source/blender/editors/uvedit/uvedit_smart_stitch.c
@@ -287,14 +287,6 @@ static void stitch_update_header(StitchStateContainer *ssc, bContext *C)
   }
 }
 
-static int getNumOfIslandUvs(UvElementMap *elementMap, int island)
-{
-  if (island == elementMap->totalIslands - 1) {
-    return elementMap->total_uvs - elementMap->islandIndices[island];
-  }
-  return elementMap->islandIndices[island + 1] - elementMap->islandIndices[island];
-}
-
 static void stitch_uv_rotate(const float mat[2][2],
                              const float medianPoint[2],
                              float uv[2],
@@ -419,10 +411,9 @@ static void stitch_calculate_island_snapping(StitchState *state,
                                              int final)
 {
   BMesh *bm = state->em->bm;
-  int i;
   UvElement *element;
 
-  for (i = 0; i < state->element_map->totalIslands; i++) {
+  for (int i = 0; i < state->element_map->total_islands; i++) {
     if (island_stitch_data[i].addedForPreview) {
       int numOfIslandUVs = 0, j;
       int totelem = island_stitch_data[i].num_rot_elements_neg +
@@ -464,8 +455,8 @@ static void stitch_calculate_island_snapping(StitchState *state,
       }
 
       angle_to_mat2(rotation_mat, rotation);
-      numOfIslandUVs = getNumOfIslandUvs(state->element_map, i);
-      element = &state->element_map->storage[state->element_map->islandIndices[i]];
+      numOfIslandUVs = state->element_map->island_total_uvs[i];
+      element = &state->element_map->storage[state->element_map->island_indices[i]];
       for (j = 0; j < numOfIslandUVs; j++, element++) {
         /* stitchable uvs have already been processed, don't process */
         if (!(element->flag & STITCH_PROCESSED)) {
@@ -984,7 +975,7 @@ static int stitch_process_data(StitchStateContainer *ssc,
     preview_position[i].data_position = STITCH_NO_PREVIEW;
   }
 
-  island_stitch_data = MEM_callocN(sizeof(*island_stitch_data) * state->element_map->totalIslands,
+  island_stitch_data = MEM_callocN(sizeof(*island_stitch_data) * state->element_map->total_islands,
                                    "stitch_island_data");
   if (!island_stitch_data) {
     return 0;
@@ -1009,7 +1000,7 @@ static int stitch_process_data(StitchStateContainer *ssc,
   }
 
   /* Remember stitchable candidates as places the 'I' button will stop at. */
-  for (int island_idx = 0; island_idx < state->element_map->totalIslands; island_idx++) {
+  for (int island_idx = 0; island_idx < state->element_map->total_islands; island_idx++) {
     state->island_is_stitchable[island_idx] = island_stitch_data[island_idx].stitchableCandidate ?
                                                   true :
                                                   false;
@@ -1017,10 +1008,10 @@ static int stitch_process_data(StitchStateContainer *ssc,
 
   if (is_active_state) {
     /* set static island to one that is added for preview */
-    ssc->static_island %= state->element_map->totalIslands;
+    ssc->static_island %= state->element_map->total_islands;
     while (!(island_stitch_data[ssc->static_island].stitchableCandidate)) {
       ssc->static_island++;
-      ssc->static_island %= state->element_map->totalIslands;
+      ssc->static_island %= state->element_map->total_islands;
       /* this is entirely possible if for example limit stitching
        * with no stitchable verts or no selection */
       if (ssc->static_island == previous_island) {
@@ -1141,13 +1132,11 @@ static int stitch_process_data(StitchStateContainer *ssc,
    * Setup preview for stitchable islands *
    ****************************************/
   if (ssc->snap_islands) {
-    for (i = 0; i < state->element_map->totalIslands; i++) {
+    for (i = 0; i < state->element_map->total_islands; i++) {
       if (island_stitch_data[i].addedForPreview) {
-        int numOfIslandUVs = 0, j;
-        UvElement *element;
-        numOfIslandUVs = getNumOfIslandUvs(state->element_map, i);
-        element = &state->element_map->storage[state->element_map->islandIndices[i]];
-        for (j = 0; j < numOfIslandUVs; j++, element++) {
+        int numOfIslandUVs = state->element_map->island_total_uvs[i];
+        UvElement *element = &state->element_map->storage[state->element_map->island_indices[i]];
+        for (int j = 0; j < numOfIslandUVs; j++, element++) {
           stitch_set_face_preview_buffer_position(element->l->f, preview, preview_position);
         }
       }
@@ -2120,8 +2109,8 @@ static StitchState *stitch_init(bContext *C,
   /***** initialize static island preview data *****/
 
   state->tris_per_island = MEM_mallocN(
-      sizeof(*state->tris_per_island) * state->element_map->totalIslands, "stitch island tris");
-  for (i = 0; i < state->element_map->totalIslands; i++) {
+      sizeof(*state->tris_per_island) * state->element_map->total_islands, "stitch island tris");
+  for (i = 0; i < state->element_map->total_islands; i++) {
     state->tris_per_island[i] = 0;
   }
 
@@ -2133,7 +2122,7 @@ static StitchState *stitch_init(bContext *C,
     }
   }
 
-  state->island_is_stitchable = MEM_callocN(sizeof(bool) * state->element_map->totalIslands,
+  state->island_is_stitchable = MEM_callocN(sizeof(bool) * state->element_map->total_islands,
                                             "stitch I stops");
   if (!state->island_is_stitchable) {
     state_delete(state);
@@ -2157,7 +2146,7 @@ static bool goto_next_island(StitchStateContainer *ssc)
 
   do {
     ssc->static_island++;
-    if (ssc->static_island >= active_state->element_map->totalIslands) {
+    if (ssc->static_island >= active_state->element_map->total_islands) {
       /* go to next object */
       ssc->active_object_index++;
       ssc->active_object_index %= ssc->objects_len;
@@ -2307,7 +2296,7 @@ static int stitch_init_all(bContext *C, wmOperator *op)
   ssc->static_island = RNA_int_get(op->ptr, "static_island");
 
   StitchState *state = ssc->states[ssc->active_object_index];
-  ssc->static_island %= state->element_map->totalIslands;
+  ssc->static_island %= state->element_map->total_islands;
 
   /* If the initial active object doesn't have any stitchable islands
    * then no active island will be seen in the UI.