Transform: Edit Mesh: Support mirror on all axes

Part of T68930

Now two other mirror options that can be enabled simultaneously: Mirror Y and Z.

Reviewers: campbellbarton

Reviewed By: campbellbarton

Subscribers: ThatAsherGuy

Differential Revision: https://developer.blender.org/D5720

7 files changed, 696 insertions, 627 deletions

diff --git a/source/blender/editors/transform/transform.c b/source/blender/editors/transform/transform.c
index d3b331faca9..ff1b9095c81 100644
--- a/source/blender/editors/transform/transform.c
+++ b/source/blender/editors/transform/transform.c
@@ -6390,367 +6390,6 @@ static void applyBoneEnvelope(TransInfo *t, const int UNUSED(mval[2]))
 /** \} */
 
 /* -------------------------------------------------------------------- */
-/* Original Data Store */
-
-/** \name Orig-Data Store Utility Functions
- * \{ */
-
-static void slide_origdata_init_flag(TransInfo *t, TransDataContainer *tc, SlideOrigData *sod)
-{
-  BMEditMesh *em = BKE_editmesh_from_object(tc->obedit);
-  BMesh *bm = em->bm;
-  const bool has_layer_math = CustomData_has_math(&bm->ldata);
-  const int cd_loop_mdisp_offset = CustomData_get_offset(&bm->ldata, CD_MDISPS);
-
-  if ((t->settings->uvcalc_flag & UVCALC_TRANSFORM_CORRECT) &&
-      /* don't do this at all for non-basis shape keys, too easy to
-       * accidentally break uv maps or vertex colors then */
-      (bm->shapenr <= 1) && (has_layer_math || (cd_loop_mdisp_offset != -1))) {
-    sod->use_origfaces = true;
-    sod->cd_loop_mdisp_offset = cd_loop_mdisp_offset;
-  }
-  else {
-    sod->use_origfaces = false;
-    sod->cd_loop_mdisp_offset = -1;
-  }
-}
-
-static void slide_origdata_init_data(TransDataContainer *tc, SlideOrigData *sod)
-{
-  if (sod->use_origfaces) {
-    BMEditMesh *em = BKE_editmesh_from_object(tc->obedit);
-    BMesh *bm = em->bm;
-
-    sod->origfaces = BLI_ghash_ptr_new(__func__);
-    sod->bm_origfaces = BM_mesh_create(&bm_mesh_allocsize_default,
-                                       &((struct BMeshCreateParams){
-                                           .use_toolflags = false,
-                                       }));
-    /* we need to have matching customdata */
-    BM_mesh_copy_init_customdata(sod->bm_origfaces, bm, NULL);
-  }
-}
-
-static void slide_origdata_create_data_vert(BMesh *bm,
-                                            SlideOrigData *sod,
-                                            TransDataGenericSlideVert *sv)
-{
-  BMIter liter;
-  int j, l_num;
-  float *loop_weights;
-
-  /* copy face data */
-  // BM_ITER_ELEM (l, &liter, sv->v, BM_LOOPS_OF_VERT) {
-  BM_iter_init(&liter, bm, BM_LOOPS_OF_VERT, sv->v);
-  l_num = liter.count;
-  loop_weights = BLI_array_alloca(loop_weights, l_num);
-  for (j = 0; j < l_num; j++) {
-    BMLoop *l = BM_iter_step(&liter);
-    BMLoop *l_prev, *l_next;
-    void **val_p;
-    if (!BLI_ghash_ensure_p(sod->origfaces, l->f, &val_p)) {
-      BMFace *f_copy = BM_face_copy(sod->bm_origfaces, bm, l->f, true, true);
-      *val_p = f_copy;
-    }
-
-    if ((l_prev = BM_loop_find_prev_nodouble(l, l->next, FLT_EPSILON)) &&
-        (l_next = BM_loop_find_next_nodouble(l, l_prev, FLT_EPSILON))) {
-      loop_weights[j] = angle_v3v3v3(l_prev->v->co, l->v->co, l_next->v->co);
-    }
-    else {
-      loop_weights[j] = 0.0f;
-    }
-  }
-
-  /* store cd_loop_groups */
-  if (sod->layer_math_map_num && (l_num != 0)) {
-    sv->cd_loop_groups = BLI_memarena_alloc(sod->arena, sod->layer_math_map_num * sizeof(void *));
-    for (j = 0; j < sod->layer_math_map_num; j++) {
-      const int layer_nr = sod->layer_math_map[j];
-      sv->cd_loop_groups[j] = BM_vert_loop_groups_data_layer_create(
-          bm, sv->v, layer_nr, loop_weights, sod->arena);
-    }
-  }
-  else {
-    sv->cd_loop_groups = NULL;
-  }
-
-  BLI_ghash_insert(sod->origverts, sv->v, sv);
-}
-
-static void slide_origdata_create_data(TransDataContainer *tc,
-                                       SlideOrigData *sod,
-                                       TransDataGenericSlideVert *sv_array,
-                                       unsigned int v_stride,
-                                       unsigned int v_num)
-{
-  if (sod->use_origfaces) {
-    BMEditMesh *em = BKE_editmesh_from_object(tc->obedit);
-    BMesh *bm = em->bm;
-    unsigned int i;
-    TransDataGenericSlideVert *sv;
-
-    int layer_index_dst;
-    int j;
-
-    layer_index_dst = 0;
-
-    /* TODO: We don't need `sod->layer_math_map` when there are no loops linked
-     * to one of the sliding vertices. */
-    if (CustomData_has_math(&bm->ldata)) {
-      /* over alloc, only 'math' layers are indexed */
-      sod->layer_math_map = MEM_mallocN(bm->ldata.totlayer * sizeof(int), __func__);
-      for (j = 0; j < bm->ldata.totlayer; j++) {
-        if (CustomData_layer_has_math(&bm->ldata, j)) {
-          sod->layer_math_map[layer_index_dst++] = j;
-        }
-      }
-      BLI_assert(layer_index_dst != 0);
-    }
-
-    sod->layer_math_map_num = layer_index_dst;
-
-    sod->arena = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
-
-    sod->origverts = BLI_ghash_ptr_new_ex(__func__, v_num);
-
-    for (i = 0, sv = sv_array; i < v_num; i++, sv = POINTER_OFFSET(sv, v_stride)) {
-      slide_origdata_create_data_vert(bm, sod, sv);
-    }
-
-    if (tc->mirror.axis_flag) {
-      TransData *td = tc->data;
-      TransDataGenericSlideVert *sv_mirror;
-
-      sod->sv_mirror = MEM_callocN(sizeof(*sv_mirror) * tc->data_len, __func__);
-      sod->totsv_mirror = tc->data_len;
-
-      sv_mirror = sod->sv_mirror;
-
-      for (i = 0; i < tc->data_len; i++, td++) {
-        BMVert *eve = td->extra;
-        /* Check the vertex has been used since both sides
-         * of the mirror may be selected & sliding. */
-        if (eve && !BLI_ghash_haskey(sod->origverts, eve)) {
-          sv_mirror->v = eve;
-          copy_v3_v3(sv_mirror->co_orig_3d, eve->co);
-
-          slide_origdata_create_data_vert(bm, sod, sv_mirror);
-          sv_mirror++;
-        }
-        else {
-          sod->totsv_mirror--;
-        }
-      }
-
-      if (sod->totsv_mirror == 0) {
-        MEM_freeN(sod->sv_mirror);
-        sod->sv_mirror = NULL;
-      }
-    }
-  }
-}
-
-/**
- * If we're sliding the vert, return its original location, if not, the current location is good.
- */
-static const float *slide_origdata_orig_vert_co(SlideOrigData *sod, BMVert *v)
-{
-  TransDataGenericSlideVert *sv = BLI_ghash_lookup(sod->origverts, v);
-  return sv ? sv->co_orig_3d : v->co;
-}
-
-static void slide_origdata_interp_data_vert(SlideOrigData *sod,
-                                            BMesh *bm,
-                                            bool is_final,
-                                            TransDataGenericSlideVert *sv)
-{
-  BMIter liter;
-  int j, l_num;
-  float *loop_weights;
-  const bool is_moved = (len_squared_v3v3(sv->v->co, sv->co_orig_3d) > FLT_EPSILON);
-  const bool do_loop_weight = sod->layer_math_map_num && is_moved;
-  const bool do_loop_mdisps = is_final && is_moved && (sod->cd_loop_mdisp_offset != -1);
-  const float *v_proj_axis = sv->v->no;
-  /* original (l->prev, l, l->next) projections for each loop ('l' remains unchanged) */
-  float v_proj[3][3];
-
-  if (do_loop_weight || do_loop_mdisps) {
-    project_plane_normalized_v3_v3v3(v_proj[1], sv->co_orig_3d, v_proj_axis);
-  }
-
-  // BM_ITER_ELEM (l, &liter, sv->v, BM_LOOPS_OF_VERT)
-  BM_iter_init(&liter, bm, BM_LOOPS_OF_VERT, sv->v);
-  l_num = liter.count;
-  loop_weights = do_loop_weight ? BLI_array_alloca(loop_weights, l_num) : NULL;
-  for (j = 0; j < l_num; j++) {
-    BMFace *f_copy; /* the copy of 'f' */
-    BMLoop *l = BM_iter_step(&liter);
-
-    f_copy = BLI_ghash_lookup(sod->origfaces, l->f);
-
-    /* only loop data, no vertex data since that contains shape keys,
-     * and we do not want to mess up other shape keys */
-    BM_loop_interp_from_face(bm, l, f_copy, false, false);
-
-    /* make sure face-attributes are correct (e.g. #MLoopUV, #MLoopCol) */
-    BM_elem_attrs_copy_ex(sod->bm_origfaces, bm, f_copy, l->f, 0x0, CD_MASK_NORMAL);
-
-    /* weight the loop */
-    if (do_loop_weight) {
-      const float eps = 1.0e-8f;
-      const BMLoop *l_prev = l->prev;
-      const BMLoop *l_next = l->next;
-      const float *co_prev = slide_origdata_orig_vert_co(sod, l_prev->v);
-      const float *co_next = slide_origdata_orig_vert_co(sod, l_next->v);
-      bool co_prev_ok;
-      bool co_next_ok;
-
-      /* In the unlikely case that we're next to a zero length edge -
-       * walk around the to the next.
-       *
-       * Since we only need to check if the vertex is in this corner,
-       * its not important _which_ loop - as long as its not overlapping
-       * 'sv->co_orig_3d', see: T45096. */
-      project_plane_normalized_v3_v3v3(v_proj[0], co_prev, v_proj_axis);
-      while (UNLIKELY(((co_prev_ok = (len_squared_v3v3(v_proj[1], v_proj[0]) > eps)) == false) &&
-                      ((l_prev = l_prev->prev) != l->next))) {
-        co_prev = slide_origdata_orig_vert_co(sod, l_prev->v);
-        project_plane_normalized_v3_v3v3(v_proj[0], co_prev, v_proj_axis);
-      }
-      project_plane_normalized_v3_v3v3(v_proj[2], co_next, v_proj_axis);
-      while (UNLIKELY(((co_next_ok = (len_squared_v3v3(v_proj[1], v_proj[2]) > eps)) == false) &&
-                      ((l_next = l_next->next) != l->prev))) {
-        co_next = slide_origdata_orig_vert_co(sod, l_next->v);
-        project_plane_normalized_v3_v3v3(v_proj[2], co_next, v_proj_axis);
-      }
-
-      if (co_prev_ok && co_next_ok) {
-        const float dist = dist_signed_squared_to_corner_v3v3v3(
-            sv->v->co, UNPACK3(v_proj), v_proj_axis);
-
-        loop_weights[j] = (dist >= 0.0f) ? 1.0f : ((dist <= -eps) ? 0.0f : (1.0f + (dist / eps)));
-        if (UNLIKELY(!isfinite(loop_weights[j]))) {
-          loop_weights[j] = 0.0f;
-        }
-      }
-      else {
-        loop_weights[j] = 0.0f;
-      }
-    }
-  }
-
-  if (sod->layer_math_map_num && sv->cd_loop_groups) {
-    if (do_loop_weight) {
-      for (j = 0; j < sod->layer_math_map_num; j++) {
-        BM_vert_loop_groups_data_layer_merge_weights(
-            bm, sv->cd_loop_groups[j], sod->layer_math_map[j], loop_weights);
-      }
-    }
-    else {
-      for (j = 0; j < sod->layer_math_map_num; j++) {
-        BM_vert_loop_groups_data_layer_merge(bm, sv->cd_loop_groups[j], sod->layer_math_map[j]);
-      }
-    }
-  }
-
-  /* Special handling for multires
-   *
-   * Interpolate from every other loop (not ideal)
-   * However values will only be taken from loops which overlap other mdisps.
-   * */
-  if (do_loop_mdisps) {
-    float(*faces_center)[3] = BLI_array_alloca(faces_center, l_num);
-    BMLoop *l;
-
-    BM_ITER_ELEM_INDEX (l, &liter, sv->v, BM_LOOPS_OF_VERT, j) {
-      BM_face_calc_center_median(l->f, faces_center[j]);
-    }
-
-    BM_ITER_ELEM_INDEX (l, &liter, sv->v, BM_LOOPS_OF_VERT, j) {
-      BMFace *f_copy = BLI_ghash_lookup(sod->origfaces, l->f);
-      float f_copy_center[3];
-      BMIter liter_other;
-      BMLoop *l_other;
-      int j_other;
-
-      BM_face_calc_center_median(f_copy, f_copy_center);
-
-      BM_ITER_ELEM_INDEX (l_other, &liter_other, sv->v, BM_LOOPS_OF_VERT, j_other) {
-        BM_face_interp_multires_ex(bm,
-                                   l_other->f,
-                                   f_copy,
-                                   faces_center[j_other],
-                                   f_copy_center,
-                                   sod->cd_loop_mdisp_offset);
-      }
-    }
-  }
-}
-
-static void slide_origdata_interp_data(Object *obedit,
-                                       SlideOrigData *sod,
-                                       TransDataGenericSlideVert *sv,
-                                       unsigned int v_stride,
-                                       unsigned int v_num,
-                                       bool is_final)
-{
-  if (sod->use_origfaces) {
-    BMEditMesh *em = BKE_editmesh_from_object(obedit);
-    BMesh *bm = em->bm;
-    unsigned int i;
-    const bool has_mdisps = (sod->cd_loop_mdisp_offset != -1);
-
-    for (i = 0; i < v_num; i++, sv = POINTER_OFFSET(sv, v_stride)) {
-
-      if (sv->cd_loop_groups || has_mdisps) {
-        slide_origdata_interp_data_vert(sod, bm, is_final, sv);
-      }
-    }
-
-    if (sod->sv_mirror) {
-      sv = sod->sv_mirror;
-      for (i = 0; i < v_num; i++, sv++) {
-        if (sv->cd_loop_groups || has_mdisps) {
-          slide_origdata_interp_data_vert(sod, bm, is_final, sv);
-        }
-      }
-    }
-  }
-}
-
-static void slide_origdata_free_date(SlideOrigData *sod)
-{
-  if (sod->use_origfaces) {
-    if (sod->bm_origfaces) {
-      BM_mesh_free(sod->bm_origfaces);
-      sod->bm_origfaces = NULL;
-    }
-
-    if (sod->origfaces) {
-      BLI_ghash_free(sod->origfaces, NULL, NULL);
-      sod->origfaces = NULL;
-    }
-
-    if (sod->origverts) {
-      BLI_ghash_free(sod->origverts, NULL, NULL);
-      sod->origverts = NULL;
-    }
-
-    if (sod->arena) {
-      BLI_memarena_free(sod->arena);
-      sod->arena = NULL;
-    }
-
-    MEM_SAFE_FREE(sod->layer_math_map);
-
-    MEM_SAFE_FREE(sod->sv_mirror);
-  }
-}
-
-/** \} */
-
-/* -------------------------------------------------------------------- */
 /* Transform (Edge Slide) */
 
 /** \name Transform Edge Slide
@@ -7201,8 +6840,6 @@ static bool createEdgeSlideVerts_double_side(TransInfo *t, TransDataContainer *t
   View3D *v3d = NULL;
   RegionView3D *rv3d = NULL;
 
-  slide_origdata_init_flag(t, tc, &sld->orig_data);
-
   sld->curr_sv_index = 0;
 
   /*ensure valid selection*/
@@ -7533,18 +7170,10 @@ static bool createEdgeSlideVerts_double_side(TransInfo *t, TransDataContainer *t
 
   calcEdgeSlide_mval_range(t, tc, sld, sv_table, loop_nr, mval, use_occlude_geometry, true);
 
-  /* create copies of faces for customdata projection */
-  bmesh_edit_begin(bm, BMO_OPTYPE_FLAG_UNTAN_MULTIRES);
-  slide_origdata_init_data(tc, &sld->orig_data);
-  slide_origdata_create_data(
-      tc, &sld->orig_data, (TransDataGenericSlideVert *)sld->sv, sizeof(*sld->sv), sld->totsv);
-
   if (rv3d) {
     calcEdgeSlide_even(t, tc, sld, mval);
   }
 
-  sld->em = em;
-
   tc->custom.mode.data = sld;
 
   MEM_freeN(sv_table);
@@ -7578,8 +7207,6 @@ static bool createEdgeSlideVerts_single_side(TransInfo *t, TransDataContainer *t
     rv3d = t->ar ? t->ar->regiondata : NULL;
   }
 
-  slide_origdata_init_flag(t, tc, &sld->orig_data);
-
   sld->curr_sv_index = 0;
   /* ensure valid selection */
   {
@@ -7728,18 +7355,10 @@ static bool createEdgeSlideVerts_single_side(TransInfo *t, TransDataContainer *t
 
   calcEdgeSlide_mval_range(t, tc, sld, sv_table, loop_nr, mval, use_occlude_geometry, false);
 
-  /* create copies of faces for customdata projection */
-  bmesh_edit_begin(bm, BMO_OPTYPE_FLAG_UNTAN_MULTIRES);
-  slide_origdata_init_data(tc, &sld->orig_data);
-  slide_origdata_create_data(
-      tc, &sld->orig_data, (TransDataGenericSlideVert *)sld->sv, sizeof(*sld->sv), sld->totsv);
-
   if (rv3d) {
     calcEdgeSlide_even(t, tc, sld, mval);
   }
 
-  sld->em = em;
-
   tc->custom.mode.data = sld;
 
   MEM_freeN(sv_table);
@@ -7756,25 +7375,10 @@ void projectEdgeSlideData(TransInfo *t, bool is_final)
       continue;
     }
 
-    SlideOrigData *sod = &sld->orig_data;
-    if (sod->use_origfaces == false) {
-      continue;
-    }
-
-    slide_origdata_interp_data(tc->obedit,
-                               sod,
-                               (TransDataGenericSlideVert *)sld->sv,
-                               sizeof(*sld->sv),
-                               sld->totsv,
-                               is_final);
+    trans_mesh_customdata_correction_apply(tc, is_final);
   }
 }
 
-void freeEdgeSlideTempFaces(EdgeSlideData *sld)
-{
-  slide_origdata_free_date(&sld->orig_data);
-}
-
 void freeEdgeSlideVerts(TransInfo *UNUSED(t),
                         TransDataContainer *UNUSED(tc),
                         TransCustomData *custom_data)
@@ -7785,10 +7389,6 @@ void freeEdgeSlideVerts(TransInfo *UNUSED(t),
     return;
   }
 
-  freeEdgeSlideTempFaces(sld);
-
-  bmesh_edit_end(sld->em->bm, BMO_OPTYPE_FLAG_UNTAN_MULTIRES);
-
   MEM_freeN(sld->sv);
   MEM_freeN(sld);
 
@@ -7847,6 +7447,8 @@ static void initEdgeSlide_ex(
     tc->custom.mode.free_cb = freeEdgeSlideVerts;
   }
 
+  trans_mesh_customdata_correction_init(t);
+
   /* set custom point first if you want value to be initialized by init */
   calcEdgeSlideCustomPoints(t);
   initMouseInputMode(t, &t->mouse, INPUT_CUSTOM_RATIO_FLIP);
@@ -8322,8 +7924,6 @@ static bool createVertSlideVerts(TransInfo *t, TransDataContainer *tc)
   VertSlideData *sld = MEM_callocN(sizeof(*sld), "sld");
   int j;
 
-  slide_origdata_init_flag(t, tc, &sld->orig_data);
-
   sld->curr_sv_index = 0;
 
   j = 0;
@@ -8387,13 +7987,6 @@ static bool createVertSlideVerts(TransInfo *t, TransDataContainer *tc)
   sld->sv = sv_array;
   sld->totsv = j;
 
-  bmesh_edit_begin(bm, BMO_OPTYPE_FLAG_UNTAN_MULTIRES);
-  slide_origdata_init_data(tc, &sld->orig_data);
-  slide_origdata_create_data(
-      tc, &sld->orig_data, (TransDataGenericSlideVert *)sld->sv, sizeof(*sld->sv), sld->totsv);
-
-  sld->em = em;
-
   tc->custom.mode.data = sld;
 
   /* most likely will be set below */
@@ -8423,23 +8016,10 @@ void projectVertSlideData(TransInfo *t, bool is_final)
 {
   FOREACH_TRANS_DATA_CONTAINER (t, tc) {
     VertSlideData *sld = tc->custom.mode.data;
-    SlideOrigData *sod = &sld->orig_data;
-    if (sod->use_origfaces == true) {
-      slide_origdata_interp_data(tc->obedit,
-                                 sod,
-                                 (TransDataGenericSlideVert *)sld->sv,
-                                 sizeof(*sld->sv),
-                                 sld->totsv,
-                                 is_final);
-    }
+    trans_mesh_customdata_correction_apply(tc, is_final);
   }
 }
 
-void freeVertSlideTempFaces(VertSlideData *sld)
-{
-  slide_origdata_free_date(&sld->orig_data);
-}
-
 void freeVertSlideVerts(TransInfo *UNUSED(t),
                         TransDataContainer *UNUSED(tc),
                         TransCustomData *custom_data)
@@ -8450,10 +8030,6 @@ void freeVertSlideVerts(TransInfo *UNUSED(t),
     return;
   }
 
-  freeVertSlideTempFaces(sld);
-
-  bmesh_edit_end(sld->em->bm, BMO_OPTYPE_FLAG_UNTAN_MULTIRES);
-
   if (sld->totsv > 0) {
     TransDataVertSlideVert *sv = sld->sv;
     int i = 0;
@@ -8503,6 +8079,8 @@ static void initVertSlide_ex(TransInfo *t, bool use_even, bool flipped, bool use
     return;
   }
 
+  trans_mesh_customdata_correction_init(t);
+
   /* set custom point first if you want value to be initialized by init */
   calcVertSlideCustomPoints(t);
   initMouseInputMode(t, &t->mouse, INPUT_CUSTOM_RATIO);
diff --git a/source/blender/editors/transform/transform.h b/source/blender/editors/transform/transform.h
index 92db32fa836..b90fff29a84 100644
--- a/source/blender/editors/transform/transform.h
+++ b/source/blender/editors/transform/transform.h
@@ -294,38 +294,11 @@ typedef struct TransDataEdgeSlideVert {
   int loop_nr;
 } TransDataEdgeSlideVert;
 
-/* store original data so we can correct UV's and similar when sliding */
-typedef struct SlideOrigData {
-  /** Set when #origfaces is initialized. */
-  bool use_origfaces;
-  int cd_loop_mdisp_offset;
-
-  /** map {BMVert: TransDataGenericSlideVert} */
-  struct GHash *origverts;
-  struct GHash *origfaces;
-  struct BMesh *bm_origfaces;
-
-  struct MemArena *arena;
-  /** Number of math BMLoop layers. */
-  int layer_math_map_num;
-  /** Array size of 'layer_math_map_num'
-   * maps TransDataVertSlideVert.cd_group index to absolute CustomData layer index */
-  int *layer_math_map;
-
-  /** Array of slide vert data especially for mirror verts. */
-  TransDataGenericSlideVert *sv_mirror;
-  int totsv_mirror;
-} SlideOrigData;
-
 typedef struct EdgeSlideData {
   TransDataEdgeSlideVert *sv;
   int totsv;
 
   int mval_start[2], mval_end[2];
-  struct BMEditMesh *em;
-
-  SlideOrigData orig_data;
-
   int curr_sv_index;
 
   /** when un-clamped - use this index: #TransDataEdgeSlideVert.dir_side */
@@ -354,11 +327,6 @@ typedef struct TransDataVertSlideVert {
 typedef struct VertSlideData {
   TransDataVertSlideVert *sv;
   int totsv;
-
-  struct BMEditMesh *em;
-
-  SlideOrigData orig_data;
-
   int curr_sv_index;
 
   /* result of ED_view3d_ob_project_mat_get */
@@ -449,6 +417,18 @@ typedef struct TransData {
   short protectflag;
 } TransData;
 
+typedef struct TransDataMirror {
+  /** location of mirrored reference data. */
+  const float *loc_src;
+  /** Location of the data to transform. */
+  float *loc_dst;
+  void *extra;
+  /* `sign` can be -2, -1, 0 or 1. */
+  int sign_x : 2;
+  int sign_y : 2;
+  int sign_z : 2;
+} TransDataMirror;
+
 typedef struct MouseInput {
   void (*apply)(struct TransInfo *t, struct MouseInput *mi, const double mval[2], float output[3]);
   void (*post)(struct TransInfo *t, float values[3]);
@@ -549,10 +529,18 @@ typedef struct TransDataContainer {
    * Mirror option
    */
   struct {
-    /* Currently for mesh X mirror only. */
-    int axis_flag;
-    /** Set to -1.0f or 1.0 when use_mirror is set. */
-    float sign;
+    union {
+      struct {
+        uint axis_x : 1;
+        uint axis_y : 1;
+        uint axis_z : 1;
+      };
+      /* For easy checking. */
+      char use_mirror_any;
+    };
+    /** Mirror data array. */
+    TransDataMirror *data;
+    int data_len;
   } mirror;
 
   TransCustomDataContainer custom;
@@ -860,16 +848,18 @@ enum {
   /** For Graph Editor - curves that can only have int-values
    * need their keyframes tagged with this. */
   TD_INTVALUES = 1 << 15,
-  /** For editmode mirror, clamp to x = 0 */
-  TD_MIRROR_EDGE = 1 << 16,
+  /** For editmode mirror, clamp axis to 0 */
+  TD_MIRROR_EDGE_X = 1 << 16,
+  TD_MIRROR_EDGE_Y = 1 << 17,
+  TD_MIRROR_EDGE_Z = 1 << 18,
   /** For fcurve handles, move them along with their keyframes */
-  TD_MOVEHANDLE1 = 1 << 17,
-  TD_MOVEHANDLE2 = 1 << 18,
+  TD_MOVEHANDLE1 = 1 << 19,
+  TD_MOVEHANDLE2 = 1 << 20,
   /** Exceptional case with pose bone rotating when a parent bone has 'Local Location'
    * option enabled and rotating also transforms it. */
-  TD_PBONE_LOCAL_MTX_P = 1 << 19,
+  TD_PBONE_LOCAL_MTX_P = 1 << 21,
   /** Same as above but for a child bone. */
-  TD_PBONE_LOCAL_MTX_C = 1 << 20,
+  TD_PBONE_LOCAL_MTX_C = 1 << 22,
 };
 
 /** #TransSnap.status */
@@ -1091,11 +1081,9 @@ int getTransformOrientation(const struct bContext *C, float normal[3], float pla
 
 void freeCustomNormalArray(TransInfo *t, TransDataContainer *tc, TransCustomData *custom_data);
 
-void freeEdgeSlideTempFaces(EdgeSlideData *sld);
 void freeEdgeSlideVerts(TransInfo *t, TransDataContainer *tc, TransCustomData *custom_data);
 void projectEdgeSlideData(TransInfo *t, bool is_final);
 
-void freeVertSlideTempFaces(VertSlideData *sld);
 void freeVertSlideVerts(TransInfo *t, TransDataContainer *tc, TransCustomData *custom_data);
 void projectVertSlideData(TransInfo *t, bool is_final);
 
diff --git a/source/blender/editors/transform/transform_convert.c b/source/blender/editors/transform/transform_convert.c
index dfdd7b71332..1e783e0e7b8 100644
--- a/source/blender/editors/transform/transform_convert.c
+++ b/source/blender/editors/transform/transform_convert.c
@@ -1778,18 +1778,16 @@ static void special_aftertrans_update__mesh(bContext *UNUSED(C), TransInfo *t)
       char hflag;
       bool has_face_sel = (bm->totfacesel != 0);
 
-      if (tc->mirror.axis_flag) {
-        TransData *td;
+      if (tc->mirror.use_mirror_any) {
+        TransDataMirror *tdm;
         int i;
 
         /* Rather then adjusting the selection (which the user would notice)
          * tag all mirrored verts, then auto-merge those. */
         BM_mesh_elem_hflag_disable_all(bm, BM_VERT, BM_ELEM_TAG, false);
 
-        for (i = 0, td = tc->data; i < tc->data_len; i++, td++) {
-          if (td->extra) {
-            BM_elem_flag_enable((BMVert *)td->extra, BM_ELEM_TAG);
-          }
+        for (i = tc->mirror.data_len, tdm = tc->mirror.data; i--; tdm++) {
+          BM_elem_flag_enable((BMVert *)tdm->extra, BM_ELEM_TAG);
         }
 
         hflag = BM_ELEM_SELECT | BM_ELEM_TAG;
@@ -1850,26 +1848,10 @@ void special_aftertrans_update(bContext *C, TransInfo *t)
            * on transform completion since it's
            * really slow -joeedh */
           projectEdgeSlideData(t, true);
-
-          FOREACH_TRANS_DATA_CONTAINER (t, tc) {
-            EdgeSlideData *sld = tc->custom.mode.data;
-
-            if (sld == NULL) {
-              continue;
-            }
-
-            /* Free temporary faces to avoid auto-merging and deleting
-             * during cleanup - psy-fi. */
-            freeEdgeSlideTempFaces(sld);
-          }
         }
         else if (t->mode == TFM_VERT_SLIDE) {
           /* as above */
           projectVertSlideData(t, true);
-          FOREACH_TRANS_DATA_CONTAINER (t, tc) {
-            VertSlideData *sld = tc->custom.mode.data;
-            freeVertSlideTempFaces(sld);
-          }
         }
 
         if (t->obedit_type == OB_MESH) {
diff --git a/source/blender/editors/transform/transform_convert.h b/source/blender/editors/transform/transform_convert.h
index 02ad4688ab6..53ff9952d05 100644
--- a/source/blender/editors/transform/transform_convert.h
+++ b/source/blender/editors/transform/transform_convert.h
@@ -69,6 +69,8 @@ void flushTransGraphData(TransInfo *t);
 void flushTransMasking(TransInfo *t);
 /* transform_convert_mesh.c */
 void flushTransUVs(TransInfo *t);
+void trans_mesh_customdata_correction_init(TransInfo *t);
+void trans_mesh_customdata_correction_apply(struct TransDataContainer *tc, bool is_final);
 /* transform_convert_node.c */
 void flushTransNodes(TransInfo *t);
 /* transform_convert_object.c */
diff --git a/source/blender/editors/transform/transform_convert_mesh.c b/source/blender/editors/transform/transform_convert_mesh.c
index 98ae15ed2dc..32239dd0bd7 100644
--- a/source/blender/editors/transform/transform_convert_mesh.c
+++ b/source/blender/editors/transform/transform_convert_mesh.c
@@ -27,8 +27,10 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "BLI_alloca.h"
 #include "BLI_bitmap.h"
 #include "BLI_math.h"
+#include "BLI_memarena.h"
 #include "BLI_linklist_stack.h"
 
 #include "BKE_context.h"
@@ -52,6 +54,9 @@
 #include "transform_convert.h"
 #include "bmesh.h"
 
+/* Used for both mirror epsilon and TD_MIRROR_EDGE_ */
+#define TRANSFORM_MAXDIST_MIRROR 0.00002f
+
 /* when transforming islands */
 struct TransIslandData {
   float co[3];
@@ -395,6 +400,164 @@ static struct TransIslandData *editmesh_islands_info_calc(BMEditMesh *em,
   return trans_islands;
 }
 
+static bool is_in_quadrant_v3(const float co[3], const int quadrant[3], const float epsilon)
+{
+  if (quadrant[0] && ((co[0] * quadrant[0]) < -epsilon)) {
+    return false;
+  }
+  if (quadrant[1] && ((co[1] * quadrant[1]) < -epsilon)) {
+    return false;
+  }
+  if (quadrant[2] && ((co[2] * quadrant[2]) < -epsilon)) {
+    return false;
+  }
+  return true;
+}
+
+static TransDataMirror *editmesh_mirror_data_calc(BMEditMesh *em,
+                                                  bool use_select,
+                                                  const bool use_topology,
+                                                  const bool mirror_axis[3],
+                                                  int *r_mirror_data_len,
+                                                  BLI_bitmap **r_mirror_bitmap)
+{
+  BMesh *bm = em->bm;
+  int *index[3] = {NULL};
+  int i;
+
+  bool test_selected_only = use_select && (mirror_axis[0] + mirror_axis[1] + mirror_axis[2]) == 1;
+  for (i = 0; i < 3; i++) {
+    if (mirror_axis[i]) {
+      index[i] = MEM_mallocN(bm->totvert * sizeof(int), __func__);
+      EDBM_verts_mirror_cache_begin_ex(
+          em, i, false, test_selected_only, use_topology, TRANSFORM_MAXDIST_MIRROR, index[i]);
+    }
+  }
+
+  BMVert *eve;
+  BMIter iter;
+
+  int quadrant[3];
+  {
+    float select_sum[3] = {0};
+    BM_ITER_MESH (eve, &iter, bm, BM_VERTS_OF_MESH) {
+      if (BM_elem_flag_test(eve, BM_ELEM_HIDDEN)) {
+        continue;
+      }
+      if (BM_elem_flag_test(eve, BM_ELEM_SELECT)) {
+        add_v3_v3(select_sum, eve->co);
+      }
+    }
+
+    for (i = 0; i < 3; i++) {
+      if (mirror_axis[i]) {
+        quadrant[i] = select_sum[i] >= 0.0f ? 1 : -1;
+      }
+      else {
+        quadrant[i] = 0;
+      }
+    }
+  }
+
+  /* Tag only elements that will be transformed within the quadrant. */
+  BM_ITER_MESH_INDEX (eve, &iter, bm, BM_VERTS_OF_MESH, i) {
+    if (BM_elem_flag_test(eve, BM_ELEM_HIDDEN)) {
+      continue;
+    }
+    if ((!use_select || BM_elem_flag_test(eve, BM_ELEM_SELECT)) &&
+        is_in_quadrant_v3(eve->co, quadrant, TRANSFORM_MAXDIST_MIRROR)) {
+      BM_elem_flag_enable(eve, BM_ELEM_TAG);
+      BM_elem_index_set(eve, i);
+    }
+    else {
+      BM_elem_flag_disable(eve, BM_ELEM_TAG);
+      BM_elem_index_set(eve, -1);
+    }
+  }
+
+  for (int a = 0; a < 3; a++) {
+    int *index_iter = index[a];
+    if (index_iter == NULL) {
+      continue;
+    }
+    BM_ITER_MESH_INDEX (eve, &iter, bm, BM_VERTS_OF_MESH, i) {
+      if (BM_elem_flag_test(eve, BM_ELEM_HIDDEN)) {
+        continue;
+      }
+      if (test_selected_only && !BM_elem_flag_test(eve, BM_ELEM_SELECT)) {
+        continue;
+      }
+      int elem_index = BM_elem_index_get(eve);
+      if (elem_index != -1) {
+        int i_mirr = index_iter[i];
+        if (i_mirr >= 0) {
+          BMVert *vmir = BM_vert_at_index(bm, i_mirr);
+          BM_elem_index_set(vmir, elem_index);
+
+          /* The slot of this element in the index array no longer needs to be read.
+           * Use to set the mirror sign. */
+          if (index[0] && a > 0) {
+            index[0][i_mirr] = index[0][i];
+          }
+          if (index[1] && a > 1) {
+            index[1][i_mirr] = index[1][i];
+          }
+          /* Use -2 to differ from -1, but both can work. */
+          index_iter[i_mirr] = -2;
+        }
+      }
+    }
+  }
+
+  /* Count mirror elements. */
+  uint mirror_elem_len = 0;
+  BM_ITER_MESH_INDEX (eve, &iter, bm, BM_VERTS_OF_MESH, i) {
+    if (BM_elem_flag_test(eve, BM_ELEM_HIDDEN | BM_ELEM_TAG)) {
+      /* Not a mirror element. */
+      BM_elem_index_set(eve, -1);
+      continue;
+    }
+    int elem_index = BM_elem_index_get(eve);
+    if (elem_index != -1) {
+      mirror_elem_len++;
+    }
+  }
+
+  TransDataMirror *mirror_data_iter, *mirror_data = NULL;
+  if (mirror_elem_len != 0) {
+    mirror_data = MEM_mallocN(mirror_elem_len * sizeof(*mirror_data), __func__);
+    mirror_data_iter = &mirror_data[0];
+
+    *r_mirror_bitmap = BLI_BITMAP_NEW(bm->totvert, __func__);
+
+    BM_ITER_MESH_INDEX (eve, &iter, bm, BM_VERTS_OF_MESH, i) {
+      int elem_index = BM_elem_index_get(eve);
+      if (elem_index != -1) {
+        BMVert *v_src = BM_vert_at_index(bm, elem_index);
+
+        mirror_data_iter->loc_src = v_src->co;
+        mirror_data_iter->loc_dst = eve->co;
+        mirror_data_iter->sign_x = index[0] && index[0][i] == -2 ? -1 : 1;
+        mirror_data_iter->sign_y = index[1] && index[1][i] == -2 ? -1 : 1;
+        mirror_data_iter->sign_z = index[2] && index[2][i] == -2 ? -1 : 1;
+        mirror_data_iter->extra = eve;
+
+        mirror_data_iter++;
+
+        BLI_BITMAP_ENABLE(*r_mirror_bitmap, i);
+      }
+    }
+  }
+
+  MEM_SAFE_FREE(index[0]);
+  MEM_SAFE_FREE(index[1]);
+  MEM_SAFE_FREE(index[2]);
+
+  bm->elem_index_dirty |= BM_VERT;
+  *r_mirror_data_len = mirror_elem_len;
+  return mirror_data;
+}
+
 /* way to overwrite what data is edited with transform */
 static void VertsToTransData(TransInfo *t,
                              TransData *td,
@@ -448,7 +611,7 @@ static void VertsToTransData(TransInfo *t,
 
   td->ext = NULL;
   td->val = NULL;
-  td->extra = NULL;
+  td->extra = eve;
   if (t->mode == TFM_BWEIGHT) {
     td->val = bweight;
     td->ival = *bweight;
@@ -487,9 +650,7 @@ void createTransEditVerts(TransInfo *t)
     float *dists = NULL;
     int a;
     const int prop_mode = (t->flag & T_PROP_EDIT) ? (t->flag & T_PROP_EDIT_ALL) : 0;
-    int mirror = 0;
     int cd_vert_bweight_offset = -1;
-    bool use_topology = (me->editflag & ME_EDIT_MIRROR_TOPO) != 0;
 
     struct TransIslandData *island_info = NULL;
     int island_info_tot;
@@ -510,11 +671,6 @@ void createTransEditVerts(TransInfo *t)
      * Optional, allocate if needed. */
     int *dists_index = NULL;
 
-    if (tc->mirror.axis_flag) {
-      EDBM_verts_mirror_cache_begin(em, 0, false, (t->flag & T_PROP_EDIT) == 0, use_topology);
-      mirror = 1;
-    }
-
     /**
      * Quick check if we can transform.
      *
@@ -531,16 +687,23 @@ void createTransEditVerts(TransInfo *t)
       cd_vert_bweight_offset = CustomData_get_offset(&bm->vdata, CD_BWEIGHT);
     }
 
+    BLI_bitmap *mirror_bitmap = NULL;
+    if (tc->mirror.use_mirror_any) {
+      bool use_topology = (me->editflag & ME_EDIT_MIRROR_TOPO) != 0;
+      bool use_select = (t->flag & T_PROP_EDIT) == 0;
+      bool mirror_axis[3] = {tc->mirror.axis_x, tc->mirror.axis_y, tc->mirror.axis_z};
+      tc->mirror.data = editmesh_mirror_data_calc(
+          em, use_select, use_topology, mirror_axis, &tc->mirror.data_len, &mirror_bitmap);
+    }
+
+    int data_len = 0;
     if (prop_mode) {
-      unsigned int count = 0;
       BM_ITER_MESH (eve, &iter, bm, BM_VERTS_OF_MESH) {
         if (!BM_elem_flag_test(eve, BM_ELEM_HIDDEN)) {
-          count++;
+          data_len++;
         }
       }
 
-      tc->data_len = count;
-
       /* allocating scratch arrays */
       if (prop_mode & T_PROP_CONNECTED) {
         dists = MEM_mallocN(em->bm->totvert * sizeof(float), __func__);
@@ -550,10 +713,23 @@ void createTransEditVerts(TransInfo *t)
       }
     }
     else {
-      tc->data_len = bm->totvertsel;
+      data_len = bm->totvertsel;
+    }
+
+    if (mirror_bitmap) {
+      BM_ITER_MESH_INDEX (eve, &iter, bm, BM_VERTS_OF_MESH, a) {
+        if (prop_mode || BM_elem_flag_test(eve, BM_ELEM_SELECT)) {
+          if (BLI_BITMAP_TEST(mirror_bitmap, a)) {
+            data_len--;
+          }
+        }
+      }
     }
 
-    tob = tc->data = MEM_callocN(tc->data_len * sizeof(TransData), "TransObData(Mesh EditMode)");
+    BLI_assert(data_len != 0);
+
+    tc->data_len = data_len;
+    tc->data = tob = MEM_callocN(data_len * sizeof(TransData), "TransObData(Mesh EditMode)");
     if (ELEM(t->mode, TFM_SKIN_RESIZE, TFM_SHRINKFATTEN)) {
       /* warning, this is overkill, we only need 2 extra floats,
        * but this stores loads of extra stuff, for TFM_SHRINKFATTEN its even more overkill
@@ -622,95 +798,91 @@ void createTransEditVerts(TransInfo *t)
       }
     }
 
-    /* find out which half we do */
-    if (mirror) {
-      BM_ITER_MESH (eve, &iter, bm, BM_VERTS_OF_MESH) {
-        if (BM_elem_flag_test(eve, BM_ELEM_SELECT) && eve->co[0] != 0.0f) {
-          if (eve->co[0] < 0.0f) {
-            tc->mirror.sign = -1.0f;
-            mirror = -1;
-          }
-          break;
-        }
+    BM_ITER_MESH_INDEX (eve, &iter, bm, BM_VERTS_OF_MESH, a) {
+      if (BM_elem_flag_test(eve, BM_ELEM_HIDDEN)) {
+        continue;
       }
-    }
+      if (mirror_bitmap && BLI_BITMAP_TEST(mirror_bitmap, a)) {
+        continue;
+      }
+      if (prop_mode || BM_elem_flag_test(eve, BM_ELEM_SELECT)) {
+        struct TransIslandData *v_island = NULL;
+        float *bweight = (cd_vert_bweight_offset != -1) ?
+                             BM_ELEM_CD_GET_VOID_P(eve, cd_vert_bweight_offset) :
+                             NULL;
+
+        if (island_info) {
+          const int connected_index = (dists_index && dists_index[a] != -1) ? dists_index[a] : a;
+          v_island = (island_vert_map[connected_index] != -1) ?
+                         &island_info[island_vert_map[connected_index]] :
+                         NULL;
+        }
 
-    BM_ITER_MESH_INDEX (eve, &iter, bm, BM_VERTS_OF_MESH, a) {
-      if (!BM_elem_flag_test(eve, BM_ELEM_HIDDEN)) {
-        if (prop_mode || BM_elem_flag_test(eve, BM_ELEM_SELECT)) {
-          struct TransIslandData *v_island = NULL;
-          float *bweight = (cd_vert_bweight_offset != -1) ?
-                               BM_ELEM_CD_GET_VOID_P(eve, cd_vert_bweight_offset) :
-                               NULL;
-
-          if (island_info) {
-            const int connected_index = (dists_index && dists_index[a] != -1) ? dists_index[a] : a;
-            v_island = (island_vert_map[connected_index] != -1) ?
-                           &island_info[island_vert_map[connected_index]] :
-                           NULL;
-          }
+        /* Do not use the island center in case we are using islands
+         * only to get axis for snap/rotate to normal... */
+        VertsToTransData(t, tob, tx, em, eve, bweight, v_island, is_snap_rotate);
+        if (tx) {
+          tx++;
+        }
 
-          /* Do not use the island center in case we are using islands
-           * only to get axis for snap/rotate to normal... */
-          VertsToTransData(t, tob, tx, em, eve, bweight, v_island, is_snap_rotate);
-          if (tx) {
-            tx++;
-          }
+        /* selected */
+        if (BM_elem_flag_test(eve, BM_ELEM_SELECT)) {
+          tob->flag |= TD_SELECTED;
+        }
 
-          /* selected */
-          if (BM_elem_flag_test(eve, BM_ELEM_SELECT)) {
-            tob->flag |= TD_SELECTED;
+        if (prop_mode) {
+          if (prop_mode & T_PROP_CONNECTED) {
+            tob->dist = dists[a];
           }
-
-          if (prop_mode) {
-            if (prop_mode & T_PROP_CONNECTED) {
-              tob->dist = dists[a];
-            }
-            else {
-              tob->flag |= TD_NOTCONNECTED;
-              tob->dist = FLT_MAX;
-            }
+          else {
+            tob->flag |= TD_NOTCONNECTED;
+            tob->dist = FLT_MAX;
           }
+        }
 
-          /* CrazySpace */
-          const bool use_quats = quats && BM_elem_flag_test(eve, BM_ELEM_TAG);
-          if (use_quats || defmats) {
-            float mat[3][3], qmat[3][3], imat[3][3];
+        /* CrazySpace */
+        const bool use_quats = quats && BM_elem_flag_test(eve, BM_ELEM_TAG);
+        if (use_quats || defmats) {
+          float mat[3][3], qmat[3][3], imat[3][3];
 
-            /* Use both or either quat and defmat correction. */
-            if (use_quats) {
-              quat_to_mat3(qmat, quats[BM_elem_index_get(eve)]);
+          /* Use both or either quat and defmat correction. */
+          if (use_quats) {
+            quat_to_mat3(qmat, quats[BM_elem_index_get(eve)]);
 
-              if (defmats) {
-                mul_m3_series(mat, defmats[a], qmat, mtx);
-              }
-              else {
-                mul_m3_m3m3(mat, mtx, qmat);
-              }
+            if (defmats) {
+              mul_m3_series(mat, defmats[a], qmat, mtx);
             }
             else {
-              mul_m3_m3m3(mat, mtx, defmats[a]);
+              mul_m3_m3m3(mat, mtx, qmat);
             }
-
-            invert_m3_m3(imat, mat);
-
-            copy_m3_m3(tob->smtx, imat);
-            copy_m3_m3(tob->mtx, mat);
           }
           else {
-            copy_m3_m3(tob->smtx, smtx);
-            copy_m3_m3(tob->mtx, mtx);
+            mul_m3_m3m3(mat, mtx, defmats[a]);
           }
 
-          /* Mirror? */
-          if ((mirror > 0 && tob->iloc[0] > 0.0f) || (mirror < 0 && tob->iloc[0] < 0.0f)) {
-            BMVert *vmir = EDBM_verts_mirror_get(em, eve);  // t->obedit, em, eve, tob->iloc, a);
-            if (vmir && vmir != eve) {
-              tob->extra = vmir;
-            }
+          invert_m3_m3(imat, mat);
+
+          copy_m3_m3(tob->smtx, imat);
+          copy_m3_m3(tob->mtx, mat);
+        }
+        else {
+          copy_m3_m3(tob->smtx, smtx);
+          copy_m3_m3(tob->mtx, mtx);
+        }
+
+        if (tc->mirror.use_mirror_any) {
+          if (tc->mirror.axis_x && fabsf(tob->loc[0]) < TRANSFORM_MAXDIST_MIRROR) {
+            tob->flag |= TD_MIRROR_EDGE_X;
+          }
+          if (tc->mirror.axis_y && fabsf(tob->loc[1]) < TRANSFORM_MAXDIST_MIRROR) {
+            tob->flag |= TD_MIRROR_EDGE_Y;
+          }
+          if (tc->mirror.axis_z && fabsf(tob->loc[2]) < TRANSFORM_MAXDIST_MIRROR) {
+            tob->flag |= TD_MIRROR_EDGE_Z;
           }
-          tob++;
         }
+
+        tob++;
       }
     }
 
@@ -719,15 +891,6 @@ void createTransEditVerts(TransInfo *t)
       MEM_freeN(island_vert_map);
     }
 
-    if (mirror != 0) {
-      tob = tc->data;
-      for (a = 0; a < tc->data_len; a++, tob++) {
-        if (ABS(tob->loc[0]) <= 0.00001f) {
-          tob->flag |= TD_MIRROR_EDGE;
-        }
-      }
-    }
-
   cleanup:
     /* crazy space free */
     if (quats) {
@@ -742,9 +905,374 @@ void createTransEditVerts(TransInfo *t)
     if (dists_index) {
       MEM_freeN(dists_index);
     }
+    if (mirror_bitmap) {
+      MEM_freeN(mirror_bitmap);
+    }
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name CustomData Layer Correction (for meshes)
+ *
+ * \{ */
+
+struct TransCustomDataLayerVert {
+  BMVert *v;
+  float co_orig_3d[3];
+  struct LinkNode **cd_loop_groups;
+};
+
+struct TransCustomDataLayer {
+  BMesh *bm;
+
+  int cd_loop_mdisp_offset;
+
+  /** map {BMVert: TransCustomDataLayerVert} */
+  struct GHash *origverts;
+  struct GHash *origfaces;
+  struct BMesh *bm_origfaces;
+
+  struct MemArena *arena;
+  /** Number of math BMLoop layers. */
+  int layer_math_map_num;
+  /** Array size of 'layer_math_map_num'
+   * maps TransCustomDataLayerVert.cd_group index to absolute CustomData layer index */
+  int *layer_math_map;
+
+  /* Array with all elements transformed. */
+  struct TransCustomDataLayerVert *data;
+  int data_len;
+};
+
+static void trans_mesh_customdata_free_cb(struct TransInfo *t,
+                                          struct TransDataContainer *tc,
+                                          struct TransCustomData *custom_data)
+{
+  struct TransCustomDataLayer *tcld = custom_data->data;
+  bmesh_edit_end(tcld->bm, BMO_OPTYPE_FLAG_UNTAN_MULTIRES);
+
+  if (tcld->bm_origfaces) {
+    BM_mesh_free(tcld->bm_origfaces);
+  }
+  if (tcld->origfaces) {
+    BLI_ghash_free(tcld->origfaces, NULL, NULL);
+  }
+  if (tcld->origverts) {
+    BLI_ghash_free(tcld->origverts, NULL, NULL);
+  }
+  if (tcld->arena) {
+    BLI_memarena_free(tcld->arena);
+  }
+  if (tcld->layer_math_map) {
+    MEM_freeN(tcld->layer_math_map);
+  }
+
+  MEM_freeN(tcld);
+  custom_data->data = NULL;
+}
+
+static void create_trans_vert_customdata_layer(BMVert *v,
+                                               struct TransCustomDataLayer *tcld,
+                                               struct TransCustomDataLayerVert *r_tcld_vert)
+{
+  BMesh *bm = tcld->bm;
+  BMIter liter;
+  int j, l_num;
+  float *loop_weights;
+
+  /* copy face data */
+  // BM_ITER_ELEM (l, &liter, sv->v, BM_LOOPS_OF_VERT) {
+  BM_iter_init(&liter, bm, BM_LOOPS_OF_VERT, v);
+  l_num = liter.count;
+  loop_weights = BLI_array_alloca(loop_weights, l_num);
+  for (j = 0; j < l_num; j++) {
+    BMLoop *l = BM_iter_step(&liter);
+    BMLoop *l_prev, *l_next;
+    void **val_p;
+    if (!BLI_ghash_ensure_p(tcld->origfaces, l->f, &val_p)) {
+      BMFace *f_copy = BM_face_copy(tcld->bm_origfaces, bm, l->f, true, true);
+      *val_p = f_copy;
+    }
+
+    if ((l_prev = BM_loop_find_prev_nodouble(l, l->next, FLT_EPSILON)) &&
+        (l_next = BM_loop_find_next_nodouble(l, l_prev, FLT_EPSILON))) {
+      loop_weights[j] = angle_v3v3v3(l_prev->v->co, l->v->co, l_next->v->co);
+    }
+    else {
+      loop_weights[j] = 0.0f;
+    }
+  }
+
+  /* store cd_loop_groups */
+  if (tcld->layer_math_map_num && (l_num != 0)) {
+    r_tcld_vert->cd_loop_groups = BLI_memarena_alloc(tcld->arena,
+                                                     tcld->layer_math_map_num * sizeof(void *));
+    for (j = 0; j < tcld->layer_math_map_num; j++) {
+      const int layer_nr = tcld->layer_math_map[j];
+      r_tcld_vert->cd_loop_groups[j] = BM_vert_loop_groups_data_layer_create(
+          bm, v, layer_nr, loop_weights, tcld->arena);
+    }
+  }
+  else {
+    r_tcld_vert->cd_loop_groups = NULL;
+  }
+
+  r_tcld_vert->v = v;
+  copy_v3_v3(r_tcld_vert->co_orig_3d, v->co);
+  BLI_ghash_insert(tcld->origverts, v, r_tcld_vert);
+}
+
+void trans_mesh_customdata_correction_init(TransInfo *t)
+{
+  FOREACH_TRANS_DATA_CONTAINER (t, tc) {
+    BLI_assert(tc->custom.type.data == NULL);
+    int i;
+
+    BMEditMesh *em = BKE_editmesh_from_object(tc->obedit);
+    BMesh *bm = em->bm;
+
+    bool use_origfaces;
+    int cd_loop_mdisp_offset;
+    {
+      const bool has_layer_math = CustomData_has_math(&bm->ldata);
+      cd_loop_mdisp_offset = CustomData_get_offset(&bm->ldata, CD_MDISPS);
+      if ((t->settings->uvcalc_flag & UVCALC_TRANSFORM_CORRECT) &&
+          /* don't do this at all for non-basis shape keys, too easy to
+           * accidentally break uv maps or vertex colors then */
+          (bm->shapenr <= 1) && (has_layer_math || (cd_loop_mdisp_offset != -1))) {
+        use_origfaces = true;
+        cd_loop_mdisp_offset = cd_loop_mdisp_offset;
+      }
+      else {
+        use_origfaces = false;
+        cd_loop_mdisp_offset = -1;
+      }
+    }
+
+    if (use_origfaces) {
+      /* create copies of faces for customdata projection */
+      bmesh_edit_begin(bm, BMO_OPTYPE_FLAG_UNTAN_MULTIRES);
+
+      struct GHash *origfaces = BLI_ghash_ptr_new(__func__);
+      struct BMesh *bm_origfaces = BM_mesh_create(&bm_mesh_allocsize_default,
+                                                  &((struct BMeshCreateParams){
+                                                      .use_toolflags = false,
+                                                  }));
+
+      /* we need to have matching customdata */
+      BM_mesh_copy_init_customdata(bm_origfaces, bm, NULL);
+
+      int *layer_math_map = NULL;
+      int layer_index_dst = 0;
+      {
+        /* TODO: We don't need `sod->layer_math_map` when there are no loops linked
+         * to one of the sliding vertices. */
+        if (CustomData_has_math(&bm->ldata)) {
+          /* over alloc, only 'math' layers are indexed */
+          layer_math_map = MEM_mallocN(bm->ldata.totlayer * sizeof(int), __func__);
+          for (i = 0; i < bm->ldata.totlayer; i++) {
+            if (CustomData_layer_has_math(&bm->ldata, i)) {
+              layer_math_map[layer_index_dst++] = i;
+            }
+          }
+          BLI_assert(layer_index_dst != 0);
+        }
+      }
+
+      struct TransCustomDataLayer *tcld;
+      tc->custom.type.data = tcld = MEM_mallocN(sizeof(*tcld), __func__);
+      tc->custom.type.free_cb = trans_mesh_customdata_free_cb;
+
+      tcld->bm = bm;
+      tcld->origfaces = origfaces;
+      tcld->bm_origfaces = bm_origfaces;
+      tcld->cd_loop_mdisp_offset = cd_loop_mdisp_offset;
+      tcld->layer_math_map = layer_math_map;
+      tcld->layer_math_map_num = layer_index_dst;
+      tcld->arena = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__);
+
+      int data_len = tc->data_len + tc->mirror.data_len;
+      struct GHash *origverts = BLI_ghash_ptr_new_ex(__func__, data_len);
+      tcld->origverts = origverts;
+
+      struct TransCustomDataLayerVert *tcld_vert, *tcld_vert_iter;
+      tcld_vert = BLI_memarena_alloc(tcld->arena, data_len * sizeof(*tcld_vert));
+      tcld_vert_iter = &tcld_vert[0];
+
+      TransData *tob;
+      for (i = tc->data_len, tob = tc->data; i--; tob++, tcld_vert_iter++) {
+        BMVert *v = tob->extra;
+        create_trans_vert_customdata_layer(v, tcld, tcld_vert_iter);
+      }
+
+      TransDataMirror *tdm;
+      for (i = tc->mirror.data_len, tdm = tc->mirror.data; i--; tdm++, tcld_vert_iter++) {
+        BMVert *v = tdm->extra;
+        create_trans_vert_customdata_layer(v, tcld, tcld_vert_iter);
+      }
+
+      tcld->data = tcld_vert;
+      tcld->data_len = data_len;
+    }
+  }
+}
+
+/**
+ * If we're sliding the vert, return its original location, if not, the current location is good.
+ */
+static const float *trans_vert_orig_co_get(struct TransCustomDataLayer *tcld, BMVert *v)
+{
+  struct TransCustomDataLayerVert *tcld_vert = BLI_ghash_lookup(tcld->origverts, v);
+  return tcld_vert ? tcld_vert->co_orig_3d : v->co;
+}
+
+static void trans_mesh_customdata_correction_apply_vert(struct TransCustomDataLayer *tcld,
+                                                        struct TransCustomDataLayerVert *tcld_vert,
+                                                        bool is_final)
+{
+  BMesh *bm = tcld->bm;
+  BMVert *v = tcld_vert->v;
+  const float *co_orig_3d = tcld_vert->co_orig_3d;
+  struct LinkNode **cd_loop_groups = tcld_vert->cd_loop_groups;
+
+  BMIter liter;
+  int j, l_num;
+  float *loop_weights;
+  const bool is_moved = (len_squared_v3v3(v->co, co_orig_3d) > FLT_EPSILON);
+  const bool do_loop_weight = tcld->layer_math_map_num && is_moved;
+  const bool do_loop_mdisps = is_final && is_moved && (tcld->cd_loop_mdisp_offset != -1);
+  const float *v_proj_axis = v->no;
+  /* original (l->prev, l, l->next) projections for each loop ('l' remains unchanged) */
+  float v_proj[3][3];
+
+  if (do_loop_weight || do_loop_mdisps) {
+    project_plane_normalized_v3_v3v3(v_proj[1], co_orig_3d, v_proj_axis);
+  }
+
+  // BM_ITER_ELEM (l, &liter, sv->v, BM_LOOPS_OF_VERT)
+  BM_iter_init(&liter, bm, BM_LOOPS_OF_VERT, v);
+  l_num = liter.count;
+  loop_weights = do_loop_weight ? BLI_array_alloca(loop_weights, l_num) : NULL;
+  for (j = 0; j < l_num; j++) {
+    BMFace *f_copy; /* the copy of 'f' */
+    BMLoop *l = BM_iter_step(&liter);
+
+    f_copy = BLI_ghash_lookup(tcld->origfaces, l->f);
+
+    /* only loop data, no vertex data since that contains shape keys,
+     * and we do not want to mess up other shape keys */
+    BM_loop_interp_from_face(bm, l, f_copy, false, false);
+
+    /* make sure face-attributes are correct (e.g. #MLoopUV, #MLoopCol) */
+    BM_elem_attrs_copy_ex(tcld->bm_origfaces, bm, f_copy, l->f, 0x0, CD_MASK_NORMAL);
+
+    /* weight the loop */
+    if (do_loop_weight) {
+      const float eps = 1.0e-8f;
+      const BMLoop *l_prev = l->prev;
+      const BMLoop *l_next = l->next;
+      const float *co_prev = trans_vert_orig_co_get(tcld, l_prev->v);
+      const float *co_next = trans_vert_orig_co_get(tcld, l_next->v);
+      bool co_prev_ok;
+      bool co_next_ok;
+
+      /* In the unlikely case that we're next to a zero length edge -
+       * walk around the to the next.
+       *
+       * Since we only need to check if the vertex is in this corner,
+       * its not important _which_ loop - as long as its not overlapping
+       * 'sv->co_orig_3d', see: T45096. */
+      project_plane_normalized_v3_v3v3(v_proj[0], co_prev, v_proj_axis);
+      while (UNLIKELY(((co_prev_ok = (len_squared_v3v3(v_proj[1], v_proj[0]) > eps)) == false) &&
+                      ((l_prev = l_prev->prev) != l->next))) {
+        co_prev = trans_vert_orig_co_get(tcld, l_prev->v);
+        project_plane_normalized_v3_v3v3(v_proj[0], co_prev, v_proj_axis);
+      }
+      project_plane_normalized_v3_v3v3(v_proj[2], co_next, v_proj_axis);
+      while (UNLIKELY(((co_next_ok = (len_squared_v3v3(v_proj[1], v_proj[2]) > eps)) == false) &&
+                      ((l_next = l_next->next) != l->prev))) {
+        co_next = trans_vert_orig_co_get(tcld, l_next->v);
+        project_plane_normalized_v3_v3v3(v_proj[2], co_next, v_proj_axis);
+      }
+
+      if (co_prev_ok && co_next_ok) {
+        const float dist = dist_signed_squared_to_corner_v3v3v3(
+            v->co, UNPACK3(v_proj), v_proj_axis);
+
+        loop_weights[j] = (dist >= 0.0f) ? 1.0f : ((dist <= -eps) ? 0.0f : (1.0f + (dist / eps)));
+        if (UNLIKELY(!isfinite(loop_weights[j]))) {
+          loop_weights[j] = 0.0f;
+        }
+      }
+      else {
+        loop_weights[j] = 0.0f;
+      }
+    }
+  }
+
+  if (tcld->layer_math_map_num && cd_loop_groups) {
+    if (do_loop_weight) {
+      for (j = 0; j < tcld->layer_math_map_num; j++) {
+        BM_vert_loop_groups_data_layer_merge_weights(
+            bm, cd_loop_groups[j], tcld->layer_math_map[j], loop_weights);
+      }
+    }
+    else {
+      for (j = 0; j < tcld->layer_math_map_num; j++) {
+        BM_vert_loop_groups_data_layer_merge(bm, cd_loop_groups[j], tcld->layer_math_map[j]);
+      }
+    }
+  }
+
+  /* Special handling for multires
+   *
+   * Interpolate from every other loop (not ideal)
+   * However values will only be taken from loops which overlap other mdisps.
+   * */
+  if (do_loop_mdisps) {
+    float(*faces_center)[3] = BLI_array_alloca(faces_center, l_num);
+    BMLoop *l;
+
+    BM_ITER_ELEM_INDEX (l, &liter, v, BM_LOOPS_OF_VERT, j) {
+      BM_face_calc_center_median(l->f, faces_center[j]);
+    }
+
+    BM_ITER_ELEM_INDEX (l, &liter, v, BM_LOOPS_OF_VERT, j) {
+      BMFace *f_copy = BLI_ghash_lookup(tcld->origfaces, l->f);
+      float f_copy_center[3];
+      BMIter liter_other;
+      BMLoop *l_other;
+      int j_other;
+
+      BM_face_calc_center_median(f_copy, f_copy_center);
+
+      BM_ITER_ELEM_INDEX (l_other, &liter_other, v, BM_LOOPS_OF_VERT, j_other) {
+        BM_face_interp_multires_ex(bm,
+                                   l_other->f,
+                                   f_copy,
+                                   faces_center[j_other],
+                                   f_copy_center,
+                                   tcld->cd_loop_mdisp_offset);
+      }
+    }
+  }
+}
+
+void trans_mesh_customdata_correction_apply(struct TransDataContainer *tc, bool is_final)
+{
+  struct TransCustomDataLayer *tcld = tc->custom.type.data;
+  if (!tcld) {
+    return;
+  }
+
+  const bool has_mdisps = (tcld->cd_loop_mdisp_offset != -1);
+  struct TransCustomDataLayerVert *tcld_vert_iter = &tcld->data[0];
 
-    if (tc->mirror.axis_flag) {
-      EDBM_verts_mirror_cache_end(em);
+  for (int i = tcld->data_len; i--; tcld_vert_iter++) {
+    if (tcld_vert_iter->cd_loop_groups || has_mdisps) {
+      trans_mesh_customdata_correction_apply_vert(tcld, tcld_vert_iter, is_final);
     }
   }
 }
diff --git a/source/blender/editors/transform/transform_generics.c b/source/blender/editors/transform/transform_generics.c
index 32d8c7381e7..e4d3c9abceb 100644
--- a/source/blender/editors/transform/transform_generics.c
+++ b/source/blender/editors/transform/transform_generics.c
@@ -224,35 +224,31 @@ static void clipMirrorModifier(TransInfo *t)
 }
 
 /* assumes obedit set to mesh object */
-static void editbmesh_apply_to_mirror(TransInfo *t)
+static void transform_apply_to_mirror(TransInfo *t)
 {
   FOREACH_TRANS_DATA_CONTAINER (t, tc) {
-    if (tc->mirror.axis_flag) {
-      TransData *td = tc->data;
-      BMVert *eve;
+    if (tc->mirror.use_mirror_any) {
       int i;
-
-      for (i = 0; i < tc->data_len; i++, td++) {
-        if (td->flag & TD_NOACTION) {
-          break;
-        }
-        if (td->loc == NULL) {
-          break;
-        }
-        if (td->flag & TD_SKIP) {
-          continue;
-        }
-
-        eve = td->extra;
-        if (eve) {
-          eve->co[0] = -td->loc[0];
-          eve->co[1] = td->loc[1];
-          eve->co[2] = td->loc[2];
+      TransData *td;
+      for (i = 0, td = tc->data; i < tc->data_len; i++, td++) {
+        if (td->flag & (TD_MIRROR_EDGE_X | TD_MIRROR_EDGE_Y | TD_MIRROR_EDGE_Z)) {
+          if (td->flag & TD_MIRROR_EDGE_X) {
+            td->loc[0] = 0.0f;
+          }
+          if (td->flag & TD_MIRROR_EDGE_Y) {
+            td->loc[1] = 0.0f;
+          }
+          if (td->flag & TD_MIRROR_EDGE_Z) {
+            td->loc[2] = 0.0f;
+          }
         }
+      }
 
-        if (td->flag & TD_MIRROR_EDGE) {
-          td->loc[0] = 0;
-        }
+      TransDataMirror *tdm;
+      for (i = 0, tdm = tc->mirror.data; i < tc->mirror.data_len; i++, tdm++) {
+        tdm->loc_dst[0] = tdm->loc_src[0] * tdm->sign_x;
+        tdm->loc_dst[1] = tdm->loc_src[1] * tdm->sign_y;
+        tdm->loc_dst[2] = tdm->loc_src[2] * tdm->sign_z;
       }
     }
   }
@@ -889,7 +885,7 @@ static void recalcData_objects(TransInfo *t)
         clipMirrorModifier(t);
       }
       if ((t->flag & T_NO_MIRROR) == 0 && (t->options & CTX_NO_MIRROR) == 0) {
-        editbmesh_apply_to_mirror(t);
+        transform_apply_to_mirror(t);
       }
 
       if (t->mode == TFM_EDGE_SLIDE) {
@@ -1361,11 +1357,12 @@ void initTransDataContainers_FromObjectData(TransInfo *t,
 
     for (int i = 0; i < objects_len; i++) {
       TransDataContainer *tc = &t->data_container[i];
-      /* TODO, multiple axes. */
-      tc->mirror.axis_flag = (((t->flag & T_NO_MIRROR) == 0) &&
-                              ((t->options & CTX_NO_MIRROR) == 0) &&
-                              (objects[i]->type == OB_MESH) &&
-                              (((Mesh *)objects[i]->data)->editflag & ME_EDIT_MIRROR_X) != 0);
+      if (((t->flag & T_NO_MIRROR) == 0) && ((t->options & CTX_NO_MIRROR) == 0) &&
+          (objects[i]->type == OB_MESH)) {
+        tc->mirror.axis_x = (((Mesh *)objects[i]->data)->editflag & ME_EDIT_MIRROR_X) != 0;
+        tc->mirror.axis_y = (((Mesh *)objects[i]->data)->editflag & ME_EDIT_MIRROR_Y) != 0;
+        tc->mirror.axis_z = (((Mesh *)objects[i]->data)->editflag & ME_EDIT_MIRROR_Z) != 0;
+      }
 
       if (object_mode & OB_MODE_EDIT) {
         tc->obedit = objects[i];
@@ -1902,6 +1899,7 @@ void postTrans(bContext *C, TransInfo *t)
 
       MEM_SAFE_FREE(tc->data_ext);
       MEM_SAFE_FREE(tc->data_2d);
+      MEM_SAFE_FREE(tc->mirror.data);
     }
   }
 
@@ -2349,11 +2347,6 @@ void calculatePropRatio(TransInfo *t)
         if (td->flag & TD_SELECTED) {
           td->factor = 1.0f;
         }
-        else if (tc->mirror.axis_flag && (td->loc[0] * tc->mirror.sign) < -0.00001f) {
-          td->flag |= TD_SKIP;
-          td->factor = 0.0f;
-          restoreElement(td);
-        }
         else if ((connected && (td->flag & TD_NOTCONNECTED || td->dist > t->prop_size)) ||
                  (connected == 0 && td->rdist > t->prop_size)) {
           /*
diff --git a/source/blender/makesrna/intern/rna_mesh.c b/source/blender/makesrna/intern/rna_mesh.c
index f7e0990aa88..be3fa5679e2 100644
--- a/source/blender/makesrna/intern/rna_mesh.c
+++ b/source/blender/makesrna/intern/rna_mesh.c
@@ -3088,7 +3088,6 @@ static void rna_def_mesh(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "X Mirror", "X Axis mirror editing");
   RNA_def_property_update(prop, 0, "rna_Mesh_update_draw");
 
-#  if 0
   prop = RNA_def_property(srna, "use_mirror_y", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "editflag", ME_EDIT_MIRROR_Y);
   RNA_def_property_ui_text(prop, "Y Mirror", "Y Axis mirror editing");
@@ -3096,7 +3095,6 @@ static void rna_def_mesh(BlenderRNA *brna)
   prop = RNA_def_property(srna, "use_mirror_z", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "editflag", ME_EDIT_MIRROR_Z);
   RNA_def_property_ui_text(prop, "Z Mirror", "Z Axis mirror editing");
-#  endif
 
   prop = RNA_def_property(srna, "use_mirror_topology", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "editflag", ME_EDIT_MIRROR_TOPO);