Editor Transform: New Snap Option Middle

Part of T66420

Reviewers: campbellbarton, brecht

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D5532

5 files changed, 71 insertions, 31 deletions

diff --git a/source/blender/editors/include/UI_icons.h b/source/blender/editors/include/UI_icons.h
index 03a49943ed3..bca0d8984c8 100644
--- a/source/blender/editors/include/UI_icons.h
+++ b/source/blender/editors/include/UI_icons.h
@@ -668,7 +668,7 @@ DEF_ICON(PARTICLE_PATH)
 DEF_ICON_BLANK(669)
 DEF_ICON_BLANK(670)
 DEF_ICON_BLANK(671)
-DEF_ICON_BLANK(672)
+DEF_ICON(SNAP_MIDPOINT)
 DEF_ICON(SNAP_OFF)
 DEF_ICON(SNAP_ON)
 DEF_ICON(SNAP_NORMAL)
diff --git a/source/blender/editors/transform/transform_snap.c b/source/blender/editors/transform/transform_snap.c
index dbcc6c1b04a..9d107527833 100644
--- a/source/blender/editors/transform/transform_snap.c
+++ b/source/blender/editors/transform/transform_snap.c
@@ -998,7 +998,8 @@ static void CalcSnapGeometry(TransInfo *t, float *UNUSED(vec))
     mval[0] = t->mval[0];
     mval[1] = t->mval[1];
 
-    if (t->tsnap.mode & (SCE_SNAP_MODE_VERTEX | SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_FACE)) {
+    if (t->tsnap.mode & (SCE_SNAP_MODE_VERTEX | SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_FACE |
+                         SCE_SNAP_MODE_EDGE_MIDPOINT)) {
       zero_v3(no); /* objects won't set this */
       found = snapObjectsTransform(t, mval, &dist_px, loc, no);
     }
diff --git a/source/blender/editors/transform/transform_snap_object.c b/source/blender/editors/transform/transform_snap_object.c
index 67bd107ab49..4943e538590 100644
--- a/source/blender/editors/transform/transform_snap_object.c
+++ b/source/blender/editors/transform/transform_snap_object.c
@@ -1260,7 +1260,7 @@ static short snap_mesh_polygon(SnapObjectContext *sctx,
 
     const MPoly *mp = &((SnapObjectData_Mesh *)sod)->poly[*r_index];
     const MLoop *ml = &treedata->loop[mp->loopstart];
-    if (snapdata->snap_to_flag & SCE_SNAP_MODE_EDGE) {
+    if (snapdata->snap_to_flag & (SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_EDGE_MIDPOINT)) {
       elem = SCE_SNAP_MODE_EDGE;
       BLI_assert(treedata->edge != NULL);
       for (int i = mp->totloop; i--; ml++) {
@@ -1297,7 +1297,7 @@ static short snap_mesh_polygon(SnapObjectContext *sctx,
     BMFace *f = BM_face_at_index(em->bm, *r_index);
     BMLoop *l_iter, *l_first;
     l_iter = l_first = BM_FACE_FIRST_LOOP(f);
-    if (snapdata->snap_to_flag & SCE_SNAP_MODE_EDGE) {
+    if (snapdata->snap_to_flag & (SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_EDGE_MIDPOINT)) {
       elem = SCE_SNAP_MODE_EDGE;
       BM_mesh_elem_index_ensure(em->bm, BM_EDGE);
       BM_mesh_elem_table_ensure(em->bm, BM_VERT | BM_EDGE);
@@ -1420,19 +1420,45 @@ static short snap_mesh_edge_verts_mixed(SnapObjectContext *sctx,
                         &lambda)) {
     /* do nothing */
   }
-  else if (lambda < 0.25f || 0.75f < lambda) {
-    int v_id = lambda < 0.5f ? 0 : 1;
+  else {
+    if (snapdata->snap_to_flag & SCE_SNAP_MODE_VERTEX) {
+      if (lambda < 0.25f || 0.75f < lambda) {
+        int v_id = lambda < 0.5f ? 0 : 1;
 
-    if (test_projected_vert_dist(&neasrest_precalc,
-                                 NULL,
-                                 0,
-                                 nearest2d.is_persp,
-                                 v_pair[v_id],
-                                 &nearest.dist_sq,
-                                 nearest.co)) {
-      nearest.index = vindex[v_id];
-      nearest2d.copy_vert_no(vindex[v_id], nearest.no, nearest2d.userdata);
-      elem = SCE_SNAP_MODE_VERTEX;
+        if (test_projected_vert_dist(&neasrest_precalc,
+                                     NULL,
+                                     0,
+                                     nearest2d.is_persp,
+                                     v_pair[v_id],
+                                     &nearest.dist_sq,
+                                     nearest.co)) {
+          nearest.index = vindex[v_id];
+          nearest2d.copy_vert_no(vindex[v_id], nearest.no, nearest2d.userdata);
+          elem = SCE_SNAP_MODE_VERTEX;
+        }
+      }
+    }
+
+    if (snapdata->snap_to_flag & SCE_SNAP_MODE_EDGE_MIDPOINT) {
+      if (0.375f < lambda && lambda < 0.625f) {
+        float vmid[3];
+        mid_v3_v3v3(vmid, v_pair[0], v_pair[1]);
+
+        if (test_projected_vert_dist(&neasrest_precalc,
+                                     NULL,
+                                     0,
+                                     nearest2d.is_persp,
+                                     vmid,
+                                     &nearest.dist_sq,
+                                     nearest.co)) {
+          float v_nor[2][3];
+          nearest2d.copy_vert_no(vindex[0], v_nor[0], nearest2d.userdata);
+          nearest2d.copy_vert_no(vindex[1], v_nor[1], nearest2d.userdata);
+          mid_v3_v3v3(nearest.no, v_nor[0], v_nor[1]);
+          nearest.index = *r_index;
+          elem = SCE_SNAP_MODE_EDGE_MIDPOINT;
+        }
+      }
     }
   }
 
@@ -1926,13 +1952,13 @@ static short snapMesh(SnapObjectContext *sctx,
 {
   BLI_assert(snapdata->snap_to_flag != SCE_SNAP_MODE_FACE);
 
-  if ((snapdata->snap_to_flag & ~SCE_SNAP_MODE_FACE) == SCE_SNAP_MODE_EDGE) {
-    if (me->totedge == 0) {
+  if ((snapdata->snap_to_flag & ~SCE_SNAP_MODE_FACE) == SCE_SNAP_MODE_VERTEX) {
+    if (me->totvert == 0) {
       return 0;
     }
   }
   else {
-    if (me->totvert == 0) {
+    if (me->totedge == 0) {
       return 0;
     }
   }
@@ -2066,7 +2092,7 @@ static short snapMesh(SnapObjectContext *sctx,
     last_index = nearest.index;
   }
 
-  if (snapdata->snap_to_flag & SCE_SNAP_MODE_EDGE) {
+  if (snapdata->snap_to_flag & (SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_EDGE_MIDPOINT)) {
     if (bvhtree[0]) {
       /* snap to loose edges */
       BLI_bvhtree_find_nearest_projected(bvhtree[0],
@@ -2164,13 +2190,13 @@ static short snapEditMesh(SnapObjectContext *sctx,
 {
   BLI_assert(snapdata->snap_to_flag != SCE_SNAP_MODE_FACE);
 
-  if ((snapdata->snap_to_flag & ~SCE_SNAP_MODE_FACE) == SCE_SNAP_MODE_EDGE) {
-    if (em->bm->totedge == 0) {
+  if ((snapdata->snap_to_flag & ~SCE_SNAP_MODE_FACE) == SCE_SNAP_MODE_VERTEX) {
+    if (em->bm->totvert == 0) {
       return 0;
     }
   }
   else {
-    if (em->bm->totvert == 0) {
+    if (em->bm->totedge == 0) {
       return 0;
     }
   }
@@ -2232,7 +2258,7 @@ static short snapEditMesh(SnapObjectContext *sctx,
     }
   }
 
-  if (snapdata->snap_to_flag & SCE_SNAP_MODE_EDGE) {
+  if (snapdata->snap_to_flag & (SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_EDGE_MIDPOINT)) {
     if (sod->bvh_trees[1] == NULL) {
       sod->bvh_trees[1] = BLI_memarena_calloc(sctx->cache.mem_arena, sizeof(**sod->bvh_trees));
     }
@@ -2304,7 +2330,8 @@ static short snapEditMesh(SnapObjectContext *sctx,
     last_index = nearest.index;
   }
 
-  if (treedata_edge && snapdata->snap_to_flag & SCE_SNAP_MODE_EDGE) {
+  if (treedata_edge &&
+      snapdata->snap_to_flag & (SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_EDGE_MIDPOINT)) {
     BM_mesh_elem_table_ensure(em->bm, BM_EDGE | BM_VERT);
     BLI_bvhtree_find_nearest_projected(treedata_edge->tree,
                                        lpmat,
@@ -2707,8 +2734,8 @@ static short transform_snap_context_project_view3d_mixed_impl(
     Object **r_ob,
     float r_obmat[4][4])
 {
-  BLI_assert((snap_to_flag & (SCE_SNAP_MODE_VERTEX | SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_FACE)) !=
-             0);
+  BLI_assert((snap_to_flag & (SCE_SNAP_MODE_VERTEX | SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_FACE |
+                              SCE_SNAP_MODE_EDGE_MIDPOINT)) != 0);
 
   short retval = 0;
   bool has_hit = false;
@@ -2733,7 +2760,7 @@ static short transform_snap_context_project_view3d_mixed_impl(
                                          ray_normal,
                                          ray_start,
                                          true)) {
-      return false;
+      return 0;
     }
 
     float dummy_ray_depth = BVH_RAYCAST_DIST_MAX;
@@ -2746,7 +2773,7 @@ static short transform_snap_context_project_view3d_mixed_impl(
     }
   }
 
-  if (snap_to_flag & (SCE_SNAP_MODE_VERTEX | SCE_SNAP_MODE_EDGE)) {
+  if (snap_to_flag & (SCE_SNAP_MODE_VERTEX | SCE_SNAP_MODE_EDGE | SCE_SNAP_MODE_EDGE_MIDPOINT)) {
     short elem;
     float dist_px_tmp = *dist_px;
 
@@ -2799,11 +2826,17 @@ static short transform_snap_context_project_view3d_mixed_impl(
       retval = elem;
     }
 
-    if ((retval == SCE_SNAP_MODE_EDGE) && (snapdata.snap_to_flag & SCE_SNAP_MODE_VERTEX)) {
-      retval = snap_mesh_edge_verts_mixed(
+    if ((retval == SCE_SNAP_MODE_EDGE) &&
+        (snap_to_flag & (SCE_SNAP_MODE_VERTEX | SCE_SNAP_MODE_EDGE_MIDPOINT))) {
+      elem = snap_mesh_edge_verts_mixed(
           sctx, &snapdata, ob, obmat, *dist_px, &dist_px_tmp, loc, no, &index);
     }
 
+    if (elem) {
+      retval = elem;
+    }
+
+    retval &= snap_to_flag;
     *dist_px = dist_px_tmp;
   }
 
diff --git a/source/blender/makesdna/DNA_scene_types.h b/source/blender/makesdna/DNA_scene_types.h
index 45159af306c..8cf7b82e1ca 100644
--- a/source/blender/makesdna/DNA_scene_types.h
+++ b/source/blender/makesdna/DNA_scene_types.h
@@ -2047,6 +2047,7 @@ enum {
 #define SCE_SNAP_MODE_FACE (1 << 2)
 #define SCE_SNAP_MODE_VOLUME (1 << 3)
 #define SCE_SNAP_MODE_INCREMENT (1 << 4)
+#define SCE_SNAP_MODE_EDGE_MIDPOINT (1 << 5)
 
 /* ToolSettings.snap_node_mode */
 #define SCE_SNAP_MODE_GRID (1 << 5)
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index 45614668475..0da96a895a9 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -167,6 +167,11 @@ const EnumPropertyItem rna_enum_snap_element_items[] = {
     {SCE_SNAP_MODE_EDGE, "EDGE", ICON_SNAP_EDGE, "Edge", "Snap to edges"},
     {SCE_SNAP_MODE_FACE, "FACE", ICON_SNAP_FACE, "Face", "Snap to faces"},
     {SCE_SNAP_MODE_VOLUME, "VOLUME", ICON_SNAP_VOLUME, "Volume", "Snap to volume"},
+    {SCE_SNAP_MODE_EDGE_MIDPOINT,
+     "EDGE_MIDPOINT",
+     ICON_SNAP_MIDPOINT,
+     "Edge Center",
+     "Snap to the middle of edges"},
     {0, NULL, 0, NULL, NULL},
 };