Fix T100370: Depth choice for "Add Cube" tool always using Surface

As the surface normal is calculated along with the coordinates, the
surface depth was always being used when surface orientation was set.

Therefore, even calculated, ignore the surface depth when it is not
required.

Also promote an optimization when neither orientation nor depth is required.

1 files changed, 86 insertions, 61 deletions

diff --git a/source/blender/editors/space_view3d/view3d_cursor_snap.c b/source/blender/editors/space_view3d/view3d_cursor_snap.c
index 4a1bd6ba945..fb44797eded 100644
--- a/source/blender/editors/space_view3d/view3d_cursor_snap.c
+++ b/source/blender/editors/space_view3d/view3d_cursor_snap.c
@@ -495,6 +495,16 @@ static void v3d_cursor_eventstate_save_xy(SnapCursorDataIntern *cursor_snap,
 }
 
 #ifdef USE_SNAP_DETECT_FROM_KEYMAP_HACK
+static void v3d_cursor_eventstate_save_modifier(SnapCursorDataIntern *data_intern,
+                                                const wmWindowManager *wm)
+{
+  if (!wm || !wm->winactive) {
+    return;
+  }
+  const wmEvent *event = wm->winactive->eventstate;
+  data_intern->last_eventstate.modifier = event->modifier;
+}
+
 static bool v3d_cursor_is_snap_invert(SnapCursorDataIntern *data_intern, const wmWindowManager *wm)
 {
   if (!wm || !wm->winactive) {
@@ -582,10 +592,14 @@ static void v3d_cursor_snap_update(V3DSnapCursorState *state,
 {
   SnapCursorDataIntern *data_intern = &g_data_intern;
   V3DSnapCursorData *snap_data = &data_intern->snap_data;
-  v3d_cursor_snap_context_ensure(scene);
+
+  const bool use_surface_nor = state->plane_orient == V3D_PLACE_ORIENT_SURFACE;
+  const bool use_surface_co = state->plane_depth == V3D_PLACE_DEPTH_SURFACE;
+  const bool calc_plane_omat = v3d_cursor_snap_calc_plane();
 
   float co[3], no[3], face_nor[3], obmat[4][4], omat[3][3];
   eSnapMode snap_elem = SCE_SNAP_MODE_NONE;
+  eSnapMode snap_elements = v3d_cursor_snap_elements(state, scene);
   int snap_elem_index[3] = {-1, -1, -1};
   int index = -1;
 
@@ -594,77 +608,84 @@ static void v3d_cursor_snap_update(V3DSnapCursorState *state,
   zero_v3(face_nor);
   unit_m3(omat);
 
-  eSnapMode snap_elements = v3d_cursor_snap_elements(state, scene);
-  data_intern->snap_elem_hidden = SCE_SNAP_MODE_NONE;
-  const bool calc_plane_omat = v3d_cursor_snap_calc_plane();
-  if (calc_plane_omat && !(snap_elements & SCE_SNAP_MODE_FACE_RAYCAST)) {
-    data_intern->snap_elem_hidden = SCE_SNAP_MODE_FACE_RAYCAST;
-    snap_elements |= SCE_SNAP_MODE_FACE_RAYCAST;
-  }
+  if (use_surface_nor || use_surface_co) {
+    v3d_cursor_snap_context_ensure(scene);
+
+    data_intern->snap_elem_hidden = SCE_SNAP_MODE_NONE;
+    if (calc_plane_omat && !(snap_elements & SCE_SNAP_MODE_FACE_RAYCAST)) {
+      data_intern->snap_elem_hidden = SCE_SNAP_MODE_FACE_RAYCAST;
+      snap_elements |= SCE_SNAP_MODE_FACE_RAYCAST;
+    }
 
-  snap_data->is_enabled = true;
+    snap_data->is_enabled = true;
 #ifdef USE_SNAP_DETECT_FROM_KEYMAP_HACK
-  if (!(state->flag & V3D_SNAPCURSOR_TOGGLE_ALWAYS_TRUE)) {
-    snap_data->is_snap_invert = v3d_cursor_is_snap_invert(data_intern, wm);
-
-    const ToolSettings *ts = scene->toolsettings;
-    if (snap_data->is_snap_invert != !(ts->snap_flag & SCE_SNAP)) {
-      snap_data->is_enabled = false;
-      if (!calc_plane_omat) {
-        snap_data->snap_elem = SCE_SNAP_MODE_NONE;
-        return;
+    if (!(state->flag & V3D_SNAPCURSOR_TOGGLE_ALWAYS_TRUE)) {
+      snap_data->is_snap_invert = v3d_cursor_is_snap_invert(data_intern, wm);
+
+      const ToolSettings *ts = scene->toolsettings;
+      if (snap_data->is_snap_invert != !(ts->snap_flag & SCE_SNAP)) {
+        snap_data->is_enabled = false;
+        if (!calc_plane_omat) {
+          snap_data->snap_elem = SCE_SNAP_MODE_NONE;
+          return;
+        }
+        snap_elements = data_intern->snap_elem_hidden = SCE_SNAP_MODE_FACE_RAYCAST;
       }
-      snap_elements = data_intern->snap_elem_hidden = SCE_SNAP_MODE_FACE_RAYCAST;
     }
-  }
 #endif
 
-  if (snap_elements & SCE_SNAP_MODE_GEOM) {
-    float prev_co[3] = {0.0f};
-    if (state->prevpoint) {
-      copy_v3_v3(prev_co, state->prevpoint);
-    }
-    else {
-      snap_elements &= ~SCE_SNAP_MODE_EDGE_PERPENDICULAR;
-    }
+    if (snap_elements & SCE_SNAP_MODE_GEOM) {
+      float prev_co[3] = {0.0f};
+      if (state->prevpoint) {
+        copy_v3_v3(prev_co, state->prevpoint);
+      }
+      else {
+        snap_elements &= ~SCE_SNAP_MODE_EDGE_PERPENDICULAR;
+      }
 
-    eSnapEditType edit_mode_type = (state->flag & V3D_SNAPCURSOR_SNAP_EDIT_GEOM_FINAL) ?
-                                       SNAP_GEOM_FINAL :
-                                   (state->flag & V3D_SNAPCURSOR_SNAP_EDIT_GEOM_CAGE) ?
-                                       SNAP_GEOM_CAGE :
-                                       SNAP_GEOM_EDIT;
-
-    bool use_occlusion_test = (state->flag & V3D_SNAPCURSOR_OCCLUSION_ALWAYS_TRUE) ? false : true;
-
-    float dist_px = 12.0f * U.pixelsize;
-
-    snap_elem = ED_transform_snap_object_project_view3d_ex(
-        data_intern->snap_context_v3d,
-        depsgraph,
-        region,
-        v3d,
-        snap_elements,
-        &(const struct SnapObjectParams){
-            .snap_target_select = SCE_SNAP_TARGET_ALL,
-            .edit_mode_type = edit_mode_type,
-            .use_occlusion_test = use_occlusion_test,
-        },
-        NULL,
-        mval_fl,
-        prev_co,
-        &dist_px,
-        co,
-        no,
-        &index,
-        NULL,
-        obmat,
-        face_nor);
+      eSnapEditType edit_mode_type = (state->flag & V3D_SNAPCURSOR_SNAP_EDIT_GEOM_FINAL) ?
+                                         SNAP_GEOM_FINAL :
+                                     (state->flag & V3D_SNAPCURSOR_SNAP_EDIT_GEOM_CAGE) ?
+                                         SNAP_GEOM_CAGE :
+                                         SNAP_GEOM_EDIT;
+
+      bool use_occlusion_test = (state->flag & V3D_SNAPCURSOR_OCCLUSION_ALWAYS_TRUE) ? false :
+                                                                                       true;
+
+      float dist_px = 12.0f * U.pixelsize;
+
+      snap_elem = ED_transform_snap_object_project_view3d_ex(
+          data_intern->snap_context_v3d,
+          depsgraph,
+          region,
+          v3d,
+          snap_elements,
+          &(const struct SnapObjectParams){
+              .snap_target_select = SCE_SNAP_TARGET_ALL,
+              .edit_mode_type = edit_mode_type,
+              .use_occlusion_test = use_occlusion_test,
+          },
+          NULL,
+          mval_fl,
+          prev_co,
+          &dist_px,
+          co,
+          no,
+          &index,
+          NULL,
+          obmat,
+          face_nor);
+    }
+  }
+#ifdef USE_SNAP_DETECT_FROM_KEYMAP_HACK
+  else {
+    v3d_cursor_eventstate_save_modifier(data_intern, wm);
   }
+#endif
 
   if (calc_plane_omat) {
     RegionView3D *rv3d = region->regiondata;
-    bool orient_surface = (snap_elem != SCE_SNAP_MODE_NONE) &&
-                          (state->plane_orient == V3D_PLACE_ORIENT_SURFACE);
+    bool orient_surface = use_surface_nor && (snap_elem != SCE_SNAP_MODE_NONE);
     if (orient_surface) {
       copy_m3_m4(omat, obmat);
     }
@@ -715,6 +736,10 @@ static void v3d_cursor_snap_update(V3DSnapCursorState *state,
     }
   }
 
+  if (!use_surface_co) {
+    snap_elem = SCE_SNAP_MODE_NONE;
+  }
+
   float *co_depth = (snap_elem != SCE_SNAP_MODE_NONE) ? co : scene->cursor.location;
   snap_elem &= ~data_intern->snap_elem_hidden;
   if (snap_elem == SCE_SNAP_MODE_NONE) {