Merge branch 'master' into retopo_transform

Differential Revision: https://developer.blender.org/D15546

release/scripts/startup/bl_ui/space_view3d.py

@@ -619,7 +619,11 @@ class VIEW3D_HT_header(Header):
         if show_snap:
             snap_items = bpy.types.ToolSettings.bl_rna.properties["snap_elements"].enum_items
             snap_elements = tool_settings.snap_elements
-            if len(snap_elements) == 1:
+            active_tool = context.workspace.tools.from_space_view3d_mode(context.mode, create=False)
+            if active_tool.idname.startswith('retopology'):
+                text = "Tool"
+                icon = 'NONE'
+            elif len(snap_elements) == 1:
                 text = ""
                 for elem in snap_elements:
                     icon = snap_items[elem].icon
@@ -632,6 +636,14 @@ class VIEW3D_HT_header(Header):
             row = layout.row(align=True)
             row.prop(tool_settings, "use_snap", text="")
 
+            if object_mode == 'EDIT' and obj.type == 'MESH':
+                row.prop(
+                    tool_settings,
+                    "use_snap_retopology_mode",
+                    text="",
+                    icon='MOD_MESHDEFORM',
+                )
+
             sub = row.row(align=True)
             sub.popover(
                 panel="VIEW3D_PT_snapping",
@@ -6808,73 +6820,106 @@ class VIEW3D_PT_snapping(Panel):
         tool_settings = context.tool_settings
         snap_elements = tool_settings.snap_elements
         obj = context.active_object
-        object_mode = 'OBJECT' if obj is None else obj.mode
+        object_mode = obj.mode if obj else 'OBJECT'
+        show_target_options = object_mode == 'EDIT' and obj.type not in {'LATTICE', 'META', 'FONT'}
+        multiple_objects = len(context.objects_in_mode) > 1
+        retopo_mode = object_mode == 'EDIT' and tool_settings.use_snap_retopology_mode
 
         layout = self.layout
         col = layout.column()
-        col.label(text="Snap To")
-        col.prop(tool_settings, "snap_elements", expand=True)
 
-        col.separator()
+        if show_target_options:
-        if 'INCREMENT' in snap_elements:
+            col.prop(
-            col.prop(tool_settings, "use_snap_grid_absolute")
+                tool_settings,
+                "use_snap_retopology_mode",
+                text="Retopology Mode",
+                # icon='MOD_MESHDEFORM',
+            )
+
+        if not retopo_mode:
+            col_snapto = col.column(align=True, heading="Snap To")
+            col_snapto.prop(tool_settings, "snap_elements", expand=True)
+        else:
+            col_snapto_edited = col.column(align=True, heading="Snap To Edited")
+            col_snapto_edited.prop_enum(tool_settings, "snap_elements", 'VERTEX')
+            col_snapto_edited.prop_enum(tool_settings, "snap_elements", 'EDGE')
+            col_snapto_edited.prop_enum(tool_settings, "snap_elements", 'EDGE_MIDPOINT')
+            col_snapto_edited.prop_enum(tool_settings, "snap_elements", 'EDGE_PERPENDICULAR')
+
+            col_snapto_nonedited = col.column(align=True, heading="Snap To Non-Edited")
+            col_snapto_nonedited.prop_enum(tool_settings, "snap_elements", 'FACE')
+            col_snapto_nonedited.prop_enum(tool_settings, "snap_elements", 'FACE_NEAREST')
+            # row = col_snapto_nonedited.row(align=True)
+            # row.enabled = False
+            # row.prop_enum(tool_settings, "snap_elements", 'FACE_NEAREST')
+
+        if not retopo_mode and snap_elements - {'INCREMENT', 'FACE_NEAREST'}:
+            col_snapwith = col.column(align=True)
+            col_snapwith.label(text='Snap With')
+            col_snapwith.row().prop(tool_settings, "snap_target", expand=True)
 
         if snap_elements != {'INCREMENT'}:
-            if snap_elements != {'FACE_NEAREST'}:
+            col_targetsel = col.column(align=True, heading="Target Selection")
-                col.label(text="Snap With")
+            if not retopo_mode and show_target_options:
-                row = col.row(align=True)
+                if not multiple_objects:
-                row.prop(tool_settings, "snap_target", expand=True)
+                    col_targetsel.prop(
-
+                        tool_settings,
-            if obj:
+                        'use_snap_self',
-                col.label(text="Target Selection")
+                        text="Include Edited",
-                col_targetsel = col.column(align=True)
+                        # description='Snap onto edited objects (Edit Mode Only)',
-                if object_mode == 'EDIT' and obj.type not in {'LATTICE', 'META', 'FONT'}:
+                        icon='EDITMODE_HLT',
+                    )
+                else:
                     col_targetsel.prop(
                         tool_settings,
                         "use_snap_self",
-                        text="Include Active",
+                        text="Include Active Edited",
+                        # description='Snap onto active edited object (Edit Mode Only)',
                         icon='EDITMODE_HLT',
                     )
                     col_targetsel.prop(
                         tool_settings,
                         "use_snap_edit",
-                        text="Include Edited",
+                        text="Include Other Edited",
+                        # description='Snap onto non-active edited object(s) (Edit Mode Only)',
                         icon='OUTLINER_DATA_MESH',
                     )
-                    col_targetsel.prop(
-                        tool_settings,
-                        "use_snap_nonedit",
-                        text="Include Non-Edited",
-                        icon='OUTLINER_OB_MESH',
-                    )
                 col_targetsel.prop(
                     tool_settings,
-                    "use_snap_selectable",
+                    "use_snap_nonedit",
-                    text="Exclude Non-Selectable",
+                    text="Include Non-Edited",
-                    icon='RESTRICT_SELECT_OFF',
+                    icon='OUTLINER_OB_MESH',
                 )
+            col_targetsel.prop(
+                tool_settings,
+                "use_snap_selectable_only",
+                text="Exclude Non-Selectable",
+                icon='RESTRICT_SELECT_OFF',
+            )
 
-                if object_mode in {'OBJECT', 'POSE', 'EDIT', 'WEIGHT_PAINT'}:
+        col_options = col.column(heading="Options")
-                    col.prop(tool_settings, "use_snap_align_rotation")
+        if 'INCREMENT' in snap_elements:
-
+            col_options.prop(tool_settings, "use_snap_grid_absolute")
-            col.prop(tool_settings, "use_snap_backface_culling")
+        if snap_elements != {'INCREMENT'}:
-
+            # TODO(@gfxcoder): Does WEIGHT_PAINT have any snapping?
-            if 'FACE' in snap_elements:
+            if object_mode in {'OBJECT', 'POSE', 'EDIT', 'WEIGHT_PAINT'}:
-                col.prop(tool_settings, "use_snap_project")
+                col_options.prop(tool_settings, "use_snap_align_rotation")
-
+            if snap_elements != {'FACE_NEAREST'}:
+                col_options.prop(tool_settings, "use_snap_backface_culling")
+            if 'FACE' in snap_elements and not retopo_mode:
+                col_options.prop(tool_settings, "use_snap_project")
             if 'FACE_NEAREST' in snap_elements:
-                col.prop(tool_settings, 'use_snap_to_same_target')
+                col_options.prop(tool_settings, 'use_snap_to_same_target')
                 if object_mode == 'EDIT':
-                    col.prop(tool_settings, 'snap_face_nearest_steps')
+                    col_options.prop(tool_settings, 'snap_face_nearest_steps')
-
             if 'VOLUME' in snap_elements:
-                col.prop(tool_settings, "use_snap_peel_object")
+                col_options.prop(tool_settings, "use_snap_peel_object")
 
-        col.label(text="Affect")
+        if not retopo_mode:
-        row = col.row(align=True)
+            row = col.row(align=True, heading="Affect")
-        row.prop(tool_settings, "use_snap_translate", text="Move", toggle=True)
+            row.prop(tool_settings, "use_snap_translate", text="Move", toggle=True)
-        row.prop(tool_settings, "use_snap_rotate", text="Rotate", toggle=True)
+            row.prop(tool_settings, "use_snap_rotate", text="Rotate", toggle=True)
-        row.prop(tool_settings, "use_snap_scale", text="Scale", toggle=True)
+            row.prop(tool_settings, "use_snap_scale", text="Scale", toggle=True)
 
 
 class VIEW3D_PT_proportional_edit(Panel):

source/blender/editors/include/ED_transform_snap_object_context.h

@@ -26,7 +26,6 @@ struct View3D;
 /* transform_snap_object.cc */
 
 /* ED_transform_snap_object_*** API */
-
 typedef enum eSnapEditType {
   SNAP_GEOM_FINAL = 0,
   SNAP_GEOM_CAGE = 1,

source/blender/editors/transform/transform_ops.c

@@ -655,6 +655,7 @@ void Transform_Properties(struct wmOperatorType *ot, int flags)
   }
 
   if (flags & P_SNAP) {
+    // TODO: rename `snap` to `use_snap`?
     prop = RNA_def_boolean(ot->srna, "snap", false, "Use Snapping Options", "");
     RNA_def_property_flag(prop, PROP_HIDDEN);
 
@@ -686,6 +687,12 @@ void Transform_Properties(struct wmOperatorType *ot, int flags)
       prop = RNA_def_boolean(
           ot->srna, "use_snap_selectable_only", false, "Target: Exclude Non-Selectable", "");
       RNA_def_property_flag(prop, PROP_HIDDEN);
+      prop = RNA_def_boolean(ot->srna,
+                             "use_snap_retopology_mode",
+                             true,
+                             "Target: Retopology Mode",
+                             "Optimize snapping options for retopology work");
+      RNA_def_property_flag(prop, PROP_HIDDEN);
 
       /* Face Nearest options */
       prop = RNA_def_boolean(

source/blender/editors/transform/transform_snap.c

@@ -128,11 +128,11 @@ bool activeSnap(const TransInfo *t)
 
 bool activeSnap_SnappingIndividual(const TransInfo *t)
 {
-  if (activeSnap(t) && t->tsnap.mode & SCE_SNAP_MODE_FACE_NEAREST) {
+  if (activeSnap(t) && (t->tsnap.mode & SCE_SNAP_MODE_FACE_NEAREST)) {
     return true;
   }
 
-  if (!t->tsnap.project) {
+  if ((t->tsnap.mode & SCE_SNAP_MODE_FACE_RAYCAST) && !t->tsnap.project) {
     return false;
   }
 
@@ -168,9 +168,22 @@ bool activeSnap_SnappingAsGroup(const TransInfo *t)
   return true;
 }
 
+static bool useSnapRetopoMode(const TransInfo *t)
+{
+  if (t->spacetype != SPACE_VIEW3D || t->obedit_type != OB_MESH) {
+    /* Not the correct context for retopology mode. */
+    return false;
+  }
+  return t->settings->snap_flag & SCE_SNAP_RETOPOLOGY_MODE;
+}
+
 bool transformModeUseSnap(const TransInfo *t)
 {
   ToolSettings *ts = t->settings;
+  if (useSnapRetopoMode(t)) {
+    /* Always use snap when retopology mode is enabled. */
+    return true;
+  }
   if (t->mode == TFM_TRANSLATION) {
     return (ts->snap_transform_mode_flag & SCE_SNAP_TRANSFORM_MODE_TRANSLATE) != 0;
   }
@@ -509,9 +522,13 @@ void applySnappingIndividual(TransInfo *t)
         continue;
       }
 
-      /* If both face ray-cast and face nearest methods are enabled, start with face ray-cast and
+      /* If both face raycast and face nearest methods are enabled, start with face raycast and
-       * fallback to face nearest ray-cast does not hit. */
+       * fallback to face nearest raycast does not hit. */
-      bool hit = applyFaceProject(t, tc, td);
+      bool hit = false;
+      if (t->tsnap.flag & SCE_SNAP_PROJECT) {
+        /* Only raycast in this function if projecting individual elements. */
+        hit = applyFaceProject(t, tc, td);
+      }
       if (!hit) {
         applyFaceNearest(t, tc, td);
       }
@@ -738,6 +755,7 @@ static eSnapTargetSelect snap_target_select_from_spacetype(TransInfo *t)
   bool use_snap_edit = (t->tsnap.target_select & SCE_SNAP_TARGET_NOT_EDITED) == 0;
   bool use_snap_nonedit = (t->tsnap.target_select & SCE_SNAP_TARGET_NOT_NONEDITED) == 0;
   bool use_snap_selectable_only = (t->tsnap.target_select & SCE_SNAP_TARGET_ONLY_SELECTABLE) != 0;
+  // bool use_retopology_mode = (t->tsnap.target_select & SCE_SNAP_TARGET_RETOPOLOGY_MODE) != 0;
 
   if (ELEM(t->spacetype, SPACE_VIEW3D, SPACE_IMAGE) && !(t->options & CTX_CAMERA)) {
     if (base_act && (base_act->object->mode & OB_MODE_PARTICLE_EDIT)) {
@@ -840,6 +858,25 @@ static void initSnappingMode(TransInfo *t)
   }
 }
 
+static void initSnappingRetopoMode(TransInfo *t)
+{
+  if (!useSnapRetopoMode(t)) {
+    /* Not using retopology mode. */
+    return;
+  }
+
+  /* Enable all possible targets.  The targets will be filtered based on snap method. */
+  t->tsnap.source_select = SCE_SNAP_SOURCE_ACTIVE;
+  t->tsnap.targetSnap = TargetSnapActive;
+  t->tsnap.target_select &= ~(SCE_SNAP_TARGET_NOT_ACTIVE | SCE_SNAP_TARGET_NOT_EDITED |
+                              SCE_SNAP_TARGET_NOT_NONEDITED);
+  t->tsnap.flag |= (SCE_SNAP_TO_INCLUDE_EDITED | SCE_SNAP_TO_INCLUDE_NONEDITED);
+  t->tsnap.flag &= ~(SCE_SNAP_NOT_TO_ACTIVE);
+  t->tsnap.mode &= ~(SCE_SNAP_MODE_INCREMENT | SCE_SNAP_MODE_GRID | SCE_SNAP_MODE_VOLUME);
+  t->tsnap.project = true;
+  t->tsnap.flag |= SCE_SNAP_PROJECT;
+}
+
 void initSnapping(TransInfo *t, wmOperator *op)
 {
   ToolSettings *ts = t->settings;
@@ -912,12 +949,19 @@ void initSnapping(TransInfo *t, wmOperator *op)
                            SCE_SNAP_TARGET_NOT_NONEDITED);
       }
 
-      if ((prop = RNA_struct_find_property(op->ptr, "use_snap_selectable")) &&
+      if ((prop = RNA_struct_find_property(op->ptr, "use_snap_selectable_only")) &&
           RNA_property_is_set(op->ptr, prop)) {
         SET_FLAG_FROM_TEST(t->tsnap.target_select,
                            RNA_property_boolean_get(op->ptr, prop),
                            SCE_SNAP_TARGET_ONLY_SELECTABLE);
       }
+
+      if ((prop = RNA_struct_find_property(op->ptr, "use_snap_retopology_mode")) &&
+          RNA_property_is_set(op->ptr, prop)) {
+        SET_FLAG_FROM_TEST(t->tsnap.target_select,
+                           RNA_property_boolean_get(op->ptr, prop),
+                           SCE_SNAP_TARGET_RETOPOLOGY_MODE);
+      }
     }
   }
   /* use scene defaults only when transform is modal */
@@ -926,9 +970,10 @@ void initSnapping(TransInfo *t, wmOperator *op)
       t->modifiers |= MOD_SNAP;
     }
 
+    t->tsnap.target_select = SCE_SNAP_TARGET_ALL;
     t->tsnap.align = ((t->tsnap.flag & SCE_SNAP_ROTATE) != 0);
     t->tsnap.project = ((t->tsnap.flag & SCE_SNAP_PROJECT) != 0);
-    t->tsnap.peel = ((t->tsnap.flag & SCE_SNAP_PROJECT) != 0);
+    t->tsnap.peel = ((t->tsnap.flag & SCE_SNAP_PEEL_OBJECT) != 0);
     SET_FLAG_FROM_TEST(t->tsnap.target_select,
                        (ts->snap_flag & SCE_SNAP_NOT_TO_ACTIVE),
                        SCE_SNAP_TARGET_NOT_ACTIVE);
@@ -941,11 +986,15 @@ void initSnapping(TransInfo *t, wmOperator *op)
     SET_FLAG_FROM_TEST(t->tsnap.target_select,
                        (ts->snap_flag & SCE_SNAP_TO_ONLY_SELECTABLE),
                        SCE_SNAP_TARGET_ONLY_SELECTABLE);
+    SET_FLAG_FROM_TEST(t->tsnap.target_select,
+                       (t->settings->snap_flag & SCE_SNAP_RETOPOLOGY_MODE),
+                       SCE_SNAP_TARGET_RETOPOLOGY_MODE);
   }
 
   t->tsnap.source_select = snap_source;
 
   initSnappingMode(t);
+  initSnappingRetopoMode(t);
 }
 
 void freeSnapping(TransInfo *t)
@@ -1446,16 +1495,28 @@ eSnapMode snapObjectsTransform(
     TransInfo *t, const float mval[2], float *dist_px, float r_loc[3], float r_no[3])
 {
   float *target = (t->tsnap.status & TARGET_INIT) ? t->tsnap.snapTarget : t->center_global;
+
+  // filter mode to group snapping modes
+  eSnapMode mode = t->tsnap.mode;
+  mode &= ~(SCE_SNAP_MODE_FACE_NEAREST);
+  if (t->tsnap.flag & SCE_SNAP_PROJECT) {
+    mode &= ~(SCE_SNAP_MODE_FACE_RAYCAST);
+  }
+
+  const bool use_retopo_mode = (t->tsnap.target_select & SCE_SNAP_TARGET_RETOPOLOGY_MODE);
+  const bool face_raycast_only = t->settings->snap_mode == SCE_SNAP_MODE_FACE_RAYCAST;
+  const bool use_occlusion_test = use_retopo_mode || !face_raycast_only;
+
   return ED_transform_snap_object_project_view3d(
       t->tsnap.object_context,
       t->depsgraph,
       t->region,
       t->view,
-      t->tsnap.mode,
+      mode,
       &(const struct SnapObjectParams){
           .snap_target_select = t->tsnap.target_select,
           .edit_mode_type = (t->flag & T_EDIT) != 0 ? SNAP_GEOM_EDIT : SNAP_GEOM_FINAL,
-          .use_occlusion_test = t->settings->snap_mode != SCE_SNAP_MODE_FACE_RAYCAST,
+          .use_occlusion_test = use_occlusion_test,
           .use_backface_culling = t->tsnap.use_backface_culling,
       },
       NULL,

source/blender/editors/transform/transform_snap_object.cc

@@ -1025,6 +1025,12 @@ static void raycast_obj_fn(SnapObjectContext *sctx,
   /* read/write args */
   float *ray_depth = dt->ray_depth;
 
+  const bool use_retopo_mode = params->snap_target_select & SCE_SNAP_TARGET_RETOPOLOGY_MODE;
+  const bool is_object_edited = BKE_object_is_in_editmode(ob_eval);
+  if (use_retopo_mode && is_object_edited) {
+    return;
+  }
+
   bool retval = false;
   if (use_occlusion_test) {
     if (ELEM(ob_eval->dt, OB_BOUNDBOX, OB_WIRE)) {
@@ -1261,7 +1267,7 @@ static bool nearest_world_tree(SnapObjectContext *UNUSED(sctx),
 
   /* compute offset between init co and prev co in local space */
   float init_co_local[3], curr_co_local[3];
-  float delta_local[3];
+  float delta_local[3], delta_step[3];
   mul_v3_m4v3(init_co_local, imat, init_co);
   mul_v3_m4v3(curr_co_local, imat, curr_co);
   sub_v3_v3v3(delta_local, curr_co_local, init_co_local);
@@ -1273,8 +1279,8 @@ static bool nearest_world_tree(SnapObjectContext *UNUSED(sctx),
   }
   else {
     /* NOTE: when `params->face_nearest_steps == 1`, the return variables of function below contain
-     * the answer.  We could return immediately after updating r_loc, r_no, r_index, but that would
+     * the answer.  We could return immediately after updating 'r_loc', 'r_no', 'r_index', but that
-     * also complicate the code. Foregoing slight optimization for code clarity. */
+     * would also complicate the code. Foregoing slight optimization for code clarity. */
     nearest_world_tree_co(
         tree, nearest_cb, treedata, curr_co_local, nullptr, nullptr, nullptr, &dist_sq);
   }
@@ -1284,8 +1290,9 @@ static bool nearest_world_tree(SnapObjectContext *UNUSED(sctx),
   *r_dist_sq = dist_sq;
 
   /* scale to make `snap_face_nearest_steps` steps */
-  float step_scale_factor = 1.0f / max_ff(1.0f, (float)params->face_nearest_steps);
+  int steps = max_ii(1, params->face_nearest_steps);
-  mul_v3_fl(delta_local, step_scale_factor);
+  float factor = 1.0f / (float)steps;
+  mul_v3_v3fl(delta_step, delta_local, factor);
 
   float co_local[3];
   float no_local[3];
@@ -1293,8 +1300,8 @@ static bool nearest_world_tree(SnapObjectContext *UNUSED(sctx),
 
   copy_v3_v3(co_local, init_co_local);
 
-  for (int i = 0; i < params->face_nearest_steps; i++) {
+  for (int i = 0; i < steps; i++) {
-    add_v3_v3(co_local, delta_local);
+    add_v3_v3(co_local, delta_step);
     nearest_world_tree_co(
         tree, nearest_cb, treedata, co_local, co_local, no_local, &index, nullptr);
   }
@@ -1384,6 +1391,12 @@ static void nearest_world_object_fn(SnapObjectContext *sctx,
 {
   struct NearestWorldObjUserData *dt = static_cast<NearestWorldObjUserData *>(data);
 
+  const bool use_retopo_mode = params->snap_target_select & SCE_SNAP_TARGET_RETOPOLOGY_MODE;
+  const bool is_object_edited = BKE_object_is_in_editmode(ob_eval);
+  if (use_retopo_mode && is_object_edited) {
+    return;
+  }
+
   bool retval = false;
   switch (ob_eval->type) {
     case OB_MESH: {
@@ -3055,6 +3068,12 @@ static void snap_obj_fn(SnapObjectContext *sctx,
   SnapObjUserData *dt = static_cast<SnapObjUserData *>(data);
   eSnapMode retval = SCE_SNAP_MODE_NONE;
 
+  const bool use_retopo_mode = (params->snap_target_select & SCE_SNAP_TARGET_RETOPOLOGY_MODE);
+  const bool is_object_edited = BKE_object_is_in_editmode(ob_eval);
+  if (use_retopo_mode && !is_object_edited) {
+    return;
+  }
+
   switch (ob_eval->type) {
     case OB_MESH: {
       const eSnapEditType edit_mode_type = params->edit_mode_type;
@@ -3384,47 +3403,29 @@ static eSnapMode transform_snap_context_project_view3d_mixed_impl(SnapObjectCont
   sctx->runtime.region = region;
   sctx->runtime.v3d = v3d;
 
-  BLI_assert((snap_to_flag & SCE_SNAP_MODE_GEOM) != 0);
+  if ((snap_to_flag & SCE_SNAP_MODE_GEOM) == 0) {
+    return SCE_SNAP_MODE_NONE;
+  }
+
+  // BLI_assert((snap_to_flag & SCE_SNAP_MODE_GEOM) != 0);
 
   eSnapMode retval = SCE_SNAP_MODE_NONE;
 
   bool has_hit = false;
   Object *ob_eval = nullptr;
+  Object *ob_ray = nullptr;
   float loc[3];
   /* Not all snapping callbacks set the normal,
    * initialize this since any hit copies both the `loc` and `no`. */
   float no[3] = {0.0f, 0.0f, 0.0f};
   float obmat[4][4];
+  float obmat_ray[4][4];
   int index = -1;
 
   const RegionView3D *rv3d = static_cast<RegionView3D *>(region->regiondata);
 
-  bool use_occlusion_test = params->use_occlusion_test && !XRAY_ENABLED(v3d);
+  const bool use_retopo_mode = params->snap_target_select & SCE_SNAP_TARGET_RETOPOLOGY_MODE;
-
+  const bool use_occlusion_test = params->use_occlusion_test && !XRAY_ENABLED(v3d);
-  /* Note: if both face raycast and face nearest are enabled, first find result of nearest, then
-   * override with raycast. */
-  if ((snap_to_flag & SCE_SNAP_MODE_FACE_NEAREST) && !has_hit) {
-    has_hit = nearestWorldObjects(
-        sctx, params, init_co, prev_co, loc, no, &index, &ob_eval, obmat);
-
-    if (has_hit) {
-      retval = SCE_SNAP_MODE_FACE_NEAREST;
-
-      copy_v3_v3(r_loc, loc);
-      if (r_no) {
-        copy_v3_v3(r_no, no);
-      }
-      if (r_ob) {
-        *r_ob = ob_eval;
-      }
-      if (r_obmat) {
-        copy_m4_m4(r_obmat, obmat);
-      }
-      if (r_index) {
-        *r_index = index;
-      }
-    }
-  }
 
   if (snap_to_flag & SCE_SNAP_MODE_FACE_RAYCAST || use_occlusion_test) {
     float ray_start[3], ray_normal[3];
@@ -3443,8 +3444,8 @@ static eSnapMode transform_snap_context_project_view3d_mixed_impl(SnapObjectCont
                              loc,
                              no,
                              &index,
-                             &ob_eval,
+                             &ob_ray,    // &ob_eval,
-                             obmat,
+                             obmat_ray,  // obmat,
                              nullptr);
 
     if (has_hit) {
@@ -3453,6 +3454,7 @@ static eSnapMode transform_snap_context_project_view3d_mixed_impl(SnapObjectCont
       }
 
       if ((snap_to_flag & SCE_SNAP_MODE_FACE_RAYCAST)) {
+        /* Record snap results only if face raycast snapping mode is enabled. */
         retval = SCE_SNAP_MODE_FACE_RAYCAST;
 
         copy_v3_v3(r_loc, loc);
@@ -3460,15 +3462,19 @@ static eSnapMode transform_snap_context_project_view3d_mixed_impl(SnapObjectCont
           copy_v3_v3(r_no, no);
         }
         if (r_ob) {
-          *r_ob = ob_eval;
+          *r_ob = ob_ray;  // ob_eval;
         }
         if (r_obmat) {
-          copy_m4_m4(r_obmat, obmat);
+          copy_m4_m4(r_obmat, obmat_ray);  // obmat
         }
         if (r_index) {
           *r_index = index;
         }
       }
+      if (use_occlusion_test && !use_retopo_mode) {
+        ob_eval = ob_ray;
+        copy_m4_m4(obmat, obmat_ray);
+      }
     }
   }
 
@@ -3503,7 +3509,7 @@ static eSnapMode transform_snap_context_project_view3d_mixed_impl(SnapObjectCont
     sctx->runtime.has_occlusion_plane = false;
 
     /* By convention we only snap to the original elements of a curve. */
-    if (has_hit && ob_eval->type != OB_CURVES_LEGACY) {
+    if (has_hit && ob_ray->type != OB_CURVES_LEGACY) {
       /* Compute the new clip_pane but do not add it yet. */
       float new_clipplane[4];
       BLI_ASSERT_UNIT_V3(no);
@@ -3517,8 +3523,9 @@ static eSnapMode transform_snap_context_project_view3d_mixed_impl(SnapObjectCont
       new_clipplane[3] += 0.01f;
 
       /* Try to snap only to the polygon. */
-      elem_test = snap_mesh_polygon(sctx, params, ob_eval, obmat, &dist_px_tmp, loc, no, &index);
+      elem_test = snap_mesh_polygon(
-      if (elem_test) {
+          sctx, params, ob_ray, obmat_ray, &dist_px_tmp, loc, no, &index);
+      if (elem_test && !use_retopo_mode) {
         elem = elem_test;
       }
 
@@ -3565,6 +3572,31 @@ static eSnapMode transform_snap_context_project_view3d_mixed_impl(SnapObjectCont
     }
   }
 
+  /* Note: if both face raycast and face nearest are enabled, first find result of nearest, then
+   * override with raycast. */
+  if ((snap_to_flag & SCE_SNAP_MODE_FACE_NEAREST) && !has_hit) {
+    has_hit = nearestWorldObjects(
+        sctx, params, init_co, prev_co, loc, no, &index, &ob_eval, obmat);
+
+    if (has_hit) {
+      retval = SCE_SNAP_MODE_FACE_NEAREST;
+
+      copy_v3_v3(r_loc, loc);
+      if (r_no) {
+        copy_v3_v3(r_no, no);
+      }
+      if (r_ob) {
+        *r_ob = ob_eval;
+      }
+      if (r_obmat) {
+        copy_m4_m4(r_obmat, obmat);
+      }
+      if (r_index) {
+        *r_index = index;
+      }
+    }
+  }
+
   return retval;
 }
 

source/blender/makesdna/DNA_scene_types.h

@@ -2095,6 +2095,7 @@ typedef enum eSnapFlag {
   SCE_SNAP_TO_INCLUDE_EDITED = (1 << 8),
   SCE_SNAP_TO_INCLUDE_NONEDITED = (1 << 9),
   SCE_SNAP_TO_ONLY_SELECTABLE = (1 << 10),
+  SCE_SNAP_RETOPOLOGY_MODE = (1 << 11),
 } eSnapFlag;
 /* Due to dependency conflicts with Cycles, header cannot directly include `BLI_utildefines.h`. */
 /* TODO: move this macro to a more general place. */
@@ -2119,6 +2120,7 @@ typedef enum eSnapTargetSelect {
   SCE_SNAP_TARGET_NOT_EDITED = (1 << 2),
   SCE_SNAP_TARGET_ONLY_SELECTABLE = (1 << 3),
   SCE_SNAP_TARGET_NOT_NONEDITED = (1 << 4),
+  SCE_SNAP_TARGET_RETOPOLOGY_MODE = (1 << 5),
 } eSnapTargetSelect;
 
 /** #ToolSettings.snap_mode */

source/blender/makesrna/intern/rna_scene.c

@@ -151,6 +151,16 @@ const EnumPropertyItem rna_enum_snap_element_items[] = {
      "Snap to increments of grid"},
     {SCE_SNAP_MODE_VERTEX, "VERTEX", ICON_SNAP_VERTEX, "Vertex", "Snap to vertices"},
     {SCE_SNAP_MODE_EDGE, "EDGE", ICON_SNAP_EDGE, "Edge", "Snap to edges"},
+    {SCE_SNAP_MODE_EDGE_MIDPOINT,
+     "EDGE_MIDPOINT",
+     ICON_SNAP_MIDPOINT,
+     "Edge Center",
+     "Snap to the middle of edges"},
+    {SCE_SNAP_MODE_EDGE_PERPENDICULAR,
+     "EDGE_PERPENDICULAR",
+     ICON_SNAP_PERPENDICULAR,
+     "Edge Perpendicular",
+     "Snap to the nearest point on an edge"},
     {SCE_SNAP_MODE_FACE_RAYCAST,
      "FACE", /* TODO(@gfxcoder): replace with "FACE_RAYCAST" as "FACE" is not descriptive. */
      ICON_SNAP_FACE,
@@ -162,16 +172,6 @@ const EnumPropertyItem rna_enum_snap_element_items[] = {
      "Face Nearest",
      "Snap to nearest point on 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"},
-    {SCE_SNAP_MODE_EDGE_PERPENDICULAR,
-     "EDGE_PERPENDICULAR",
-     ICON_SNAP_PERPENDICULAR,
-     "Edge Perpendicular",
-     "Snap to the nearest point on an edge"},
     {0, NULL, 0, NULL, NULL},
 };
 
@@ -3313,10 +3313,10 @@ static void rna_def_tool_settings(BlenderRNA *brna)
   prop = RNA_def_property(srna, "snap_face_nearest_steps", PROP_INT, PROP_FACTOR);
   RNA_def_property_int_sdna(prop, NULL, "snap_face_nearest_steps");
   RNA_def_property_range(prop, 1, 100);
-  RNA_def_property_ui_text(
+  RNA_def_property_ui_text(prop,
-      prop,
+                           "Face Nearest Steps",
-      "Face Nearest Steps",
+                           "Increase precision and smooth large changes by dividing "
-      "Number of steps to break transformation into for face nearest snapping");
+                           "transformation into smaller steps (Face Nearest Only)");
 
   prop = RNA_def_property(srna, "use_snap_to_same_target", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "snap_flag", SCE_SNAP_KEEP_ON_SAME_OBJECT);
@@ -3379,13 +3379,13 @@ static void rna_def_tool_settings(BlenderRNA *brna)
   prop = RNA_def_property(srna, "use_snap_self", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_negative_sdna(prop, NULL, "snap_flag", SCE_SNAP_NOT_TO_ACTIVE);
   RNA_def_property_ui_text(
-      prop, "Snap onto Active", "Snap onto itself only if enabled (Edit Mode Only)");
+      prop, "Snap onto Active", "Snap onto active edited object (Edit Mode Only)");
   RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL); /* header redraw */
 
   prop = RNA_def_property(srna, "use_snap_edit", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "snap_flag", SCE_SNAP_TO_INCLUDE_EDITED);
   RNA_def_property_ui_text(
-      prop, "Snap onto Edited", "Snap onto non-active objects in Edit Mode (Edit Mode Only)");
+      prop, "Snap onto Edited", "Snap onto non-active edited objects (Edit Mode Only)");
   RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL); /* header redraw */
 
   prop = RNA_def_property(srna, "use_snap_nonedit", PROP_BOOLEAN, PROP_NONE);
@@ -3394,12 +3394,18 @@ static void rna_def_tool_settings(BlenderRNA *brna)
       prop, "Snap onto Non-edited", "Snap onto objects not in Edit Mode (Edit Mode Only)");
   RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL); /* header redraw */
 
-  prop = RNA_def_property(srna, "use_snap_selectable", PROP_BOOLEAN, PROP_NONE);
+  prop = RNA_def_property(srna, "use_snap_selectable_only", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "snap_flag", SCE_SNAP_TO_ONLY_SELECTABLE);
   RNA_def_property_ui_text(
       prop, "Snap onto Selectable Only", "Snap only onto objects that are selectable");
   RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL); /* header redraw */
 
+  prop = RNA_def_property(srna, "use_snap_retopology_mode", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "snap_flag", SCE_SNAP_RETOPOLOGY_MODE);
+  RNA_def_property_ui_text(
+      prop, "Retopology Snapping Mode", "Optimize snapping options for retopology work");
+  RNA_def_property_update(prop, NC_SCENE | ND_TOOLSETTINGS, NULL); /* header redraw */
+
   prop = RNA_def_property(srna, "use_snap_translate", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(
       prop, NULL, "snap_transform_mode_flag", SCE_SNAP_TRANSFORM_MODE_TRANSLATE);

source/blender/makesrna/intern/rna_wm_api.c

@@ -714,6 +714,11 @@ void RNA_api_window(StructRNA *srna)
   FunctionRNA *func;
   PropertyRNA *parm;
 
+  func = RNA_def_function(srna, "is_operator_modal", "WM_active_modal_operator_test");
+  RNA_def_function_ui_description(func, "Test if an operator is actively running modal.");
+  parm = RNA_def_boolean(func, "result", 0, "", "Operator running modal");
+  RNA_def_function_return(func, parm);
+
   func = RNA_def_function(srna, "cursor_warp", "WM_cursor_warp");
   parm = RNA_def_int(func, "x", 0, INT_MIN, INT_MAX, "", "", INT_MIN, INT_MAX);
   RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
@@ -721,6 +726,13 @@ void RNA_api_window(StructRNA *srna)
   RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
   RNA_def_function_ui_description(func, "Set the cursor position");
 
+  func = RNA_def_function(srna, "cursor_warp_relative", "WM_cursor_warp_relative");
+  parm = RNA_def_int(func, "x", 0, INT_MIN, INT_MAX, "", "Offset of x", INT_MIN, INT_MAX);
+  RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+  parm = RNA_def_int(func, "y", 0, INT_MIN, INT_MAX, "", "Offset of y", INT_MIN, INT_MAX);
+  RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+  RNA_def_function_ui_description(func, "Offset the cursor position");
+
   func = RNA_def_function(srna, "cursor_set", "WM_cursor_set");
   parm = RNA_def_property(func, "cursor", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_items(parm, rna_enum_window_cursor_items);

source/blender/windowmanager/WM_api.h

@@ -310,10 +310,20 @@ void WM_paint_cursor_remove_by_type(struct wmWindowManager *wm,
                                     void (*free)(void *));
 void WM_paint_cursor_tag_redraw(struct wmWindow *win, struct ARegion *region);
 
+/**
+ * Determines whether an operator is actively running modal.
+ */
+bool WM_active_modal_operator_test(struct wmWindow *win);
+
 /**
  * This function requires access to the GHOST_SystemHandle (g_system).
  */
 void WM_cursor_warp(struct wmWindow *win, int x, int y);
+void WM_cursor_warp_relative(struct wmWindow *win, int x, int y);
+/**
+ * Set x, y to values we can actually position the cursor to.
+ */
+void WM_cursor_compatible_xy(wmWindow *win, int *x, int *y);
 
 /* Handlers. */
 

source/blender/windowmanager/intern/wm_cursors.c

@@ -278,14 +278,6 @@ void WM_cursor_grab_disable(wmWindow *win, const int mouse_ungrab_xy[2])
   }
 }
 
-static void wm_cursor_warp_relative(wmWindow *win, int x, int y)
-{
-  /* NOTE: don't use wmEvent coords because of continuous grab T36409. */
-  int cx, cy;
-  wm_cursor_position_get(win, &cx, &cy);
-  WM_cursor_warp(win, cx + x, cy + y);
-}
-
 bool wm_cursor_arrow_move(wmWindow *win, const wmEvent *event)
 {
   /* TODO: give it a modal keymap? Hard coded for now */
@@ -295,19 +287,19 @@ bool wm_cursor_arrow_move(wmWindow *win, const wmEvent *event)
     float fac = GHOST_GetNativePixelSize(win->ghostwin);
 
     if (event->type == EVT_UPARROWKEY) {
-      wm_cursor_warp_relative(win, 0, fac);
+      WM_cursor_warp_relative(win, 0, fac);
       return 1;
     }
     if (event->type == EVT_DOWNARROWKEY) {
-      wm_cursor_warp_relative(win, 0, -fac);
+      WM_cursor_warp_relative(win, 0, -fac);
       return 1;
     }
     if (event->type == EVT_LEFTARROWKEY) {
-      wm_cursor_warp_relative(win, -fac, 0);
+      WM_cursor_warp_relative(win, -fac, 0);
       return 1;
     }
     if (event->type == EVT_RIGHTARROWKEY) {
-      wm_cursor_warp_relative(win, fac, 0);
+      WM_cursor_warp_relative(win, fac, 0);
       return 1;
     }
   }

source/blender/windowmanager/intern/wm_window.c

@@ -2000,6 +2000,22 @@ void WM_init_native_pixels(bool do_it)
 
 /** \} */
 
+/* -------------------------------------------------------------------- */
+/** \name Operator API
+ * \{ */
+
+bool WM_active_modal_operator_test(struct wmWindow *win)
+{
+  LISTBASE_FOREACH (wmEventHandler *, handler_base, &win->modalhandlers) {
+    if (handler_base->type == WM_HANDLER_TYPE_OP) {
+      return true;
+    }
+  }
+  return false;
+}
+
+/** \} */
+
 /* -------------------------------------------------------------------- */
 /** \name Cursor API
  * \{ */
@@ -2038,6 +2054,25 @@ void WM_cursor_warp(wmWindow *win, int x, int y)
   }
 }
 
+void WM_cursor_warp_relative(wmWindow *win, int x, int y)
+{
+  if (win && win->ghostwin) {
+    /* NOTE: don't use wmEvent coords because of continuous grab T36409. */
+    int cx, cy;
+    wm_cursor_position_get(win, &cx, &cy);
+    WM_cursor_warp(win, cx + x, cy + y);
+  }
+}
+
+void WM_cursor_compatible_xy(wmWindow *win, int *x, int *y)
+{
+  float f = GHOST_GetNativePixelSize(win->ghostwin);
+  if (f != 1.0f) {
+    *x = (int)(*x / f) * f;
+    *y = (int)(*y / f) * f;
+  }
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */