Fix 3D smooth-view ignoring lens when exiting camera view

Add NULL checks for `sview->ofs`, while it's currently never NULL
when a camera is set. The API allows for each member
to be set independently.

3 files changed, 15 insertions, 5 deletions

diff --git a/source/blender/editors/space_view3d/view3d_edit.c b/source/blender/editors/space_view3d/view3d_edit.c
index 83a2254e811..7ec6bddd6a3 100644
--- a/source/blender/editors/space_view3d/view3d_edit.c
+++ b/source/blender/editors/space_view3d/view3d_edit.c
@@ -3910,6 +3910,7 @@ static void axis_set_view(bContext *C,
                           region,
                           smooth_viewtx,
                           &(const V3D_SmoothParams){
+                              .camera_old = camera_eval,
                               .ofs = ofs,
                               .quat = quat,
                               .dist = &dist,
diff --git a/source/blender/editors/space_view3d/view3d_intern.h b/source/blender/editors/space_view3d/view3d_intern.h
index 87a971f1ca3..b23b9db3211 100644
--- a/source/blender/editors/space_view3d/view3d_intern.h
+++ b/source/blender/editors/space_view3d/view3d_intern.h
@@ -170,10 +170,16 @@ bool ED_view3d_boundbox_clip_ex(const RegionView3D *rv3d,
                                 float obmat[4][4]);
 bool ED_view3d_boundbox_clip(RegionView3D *rv3d, const struct BoundBox *bb);
 
+/**
+ * Parameters for setting the new view-port state.
+ *
+ * Each of the struct members may be NULL to signify they aren't to be adjusted.
+ */
 typedef struct V3D_SmoothParams {
   struct Object *camera_old, *camera;
   const float *ofs, *quat, *dist, *lens;
-  /* alternate rotation center (ofs = must be NULL) */
+
+  /** Alternate rotation center, when set `ofs` must be NULL. */
   const float *dyn_ofs;
 } V3D_SmoothParams;
 
diff --git a/source/blender/editors/space_view3d/view3d_view.c b/source/blender/editors/space_view3d/view3d_view.c
index 0f0a710a82a..a24f59019f0 100644
--- a/source/blender/editors/space_view3d/view3d_view.c
+++ b/source/blender/editors/space_view3d/view3d_view.c
@@ -192,8 +192,10 @@ void ED_view3d_smooth_view_ex(
 
   if (sview->camera) {
     Object *ob_camera_eval = DEG_get_evaluated_object(depsgraph, sview->camera);
-    sms.dst.dist = ED_view3d_offset_distance(
-        ob_camera_eval->obmat, sview->ofs, VIEW3D_DIST_FALLBACK);
+    if (sview->ofs != NULL) {
+      sms.dst.dist = ED_view3d_offset_distance(
+          ob_camera_eval->obmat, sview->ofs, VIEW3D_DIST_FALLBACK);
+    }
     ED_view3d_from_object(ob_camera_eval, sms.dst.ofs, sms.dst.quat, &sms.dst.dist, &sms.dst.lens);
     sms.to_camera = true; /* restore view3d values in end */
   }
@@ -224,8 +226,9 @@ void ED_view3d_smooth_view_ex(
       /* original values */
       if (sview->camera_old) {
         Object *ob_camera_old_eval = DEG_get_evaluated_object(depsgraph, sview->camera_old);
-        sms.src.dist = ED_view3d_offset_distance(ob_camera_old_eval->obmat, rv3d->ofs, 0.0f);
-        /* this */
+        if (sview->ofs != NULL) {
+          sms.src.dist = ED_view3d_offset_distance(ob_camera_old_eval->obmat, sview->ofs, 0.0f);
+        }
         ED_view3d_from_object(
             ob_camera_old_eval, sms.src.ofs, sms.src.quat, &sms.src.dist, &sms.src.lens);
       }