Use Ctrl Snap to seconds w/ play-head drag

D3056 by @alourenco

2 files changed, 12 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_scene.h b/source/blender/blenkernel/BKE_scene.h
index ae809641480..e85867fcbe7 100644
--- a/source/blender/blenkernel/BKE_scene.h
+++ b/source/blender/blenkernel/BKE_scene.h
@@ -114,6 +114,8 @@ int BKE_scene_camera_switch_update(struct Scene *scene);
 char *BKE_scene_find_marker_name(struct Scene *scene, int frame);
 char *BKE_scene_find_last_marker_name(struct Scene *scene, int frame);
 
+int BKE_scene_frame_snap_by_seconds(struct Scene *scene, double interval_in_seconds, int cfra);
+
 /* checks for cycle, returns 1 if it's all OK */
 bool BKE_scene_validate_setscene(struct Main *bmain, struct Scene *sce);
 
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index a1003910ca3..1eb65519596 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -1204,6 +1204,16 @@ char *BKE_scene_find_last_marker_name(Scene *scene, int frame)
 	return best_marker ? best_marker->name : NULL;
 }
 
+int BKE_scene_frame_snap_by_seconds(Scene *scene, double interval_in_seconds, int cfra)
+{
+	const int fps = round_db_to_int(FPS * interval_in_seconds);
+	const int second_prev = cfra - mod_i(cfra, fps);
+	const int second_next = second_prev + fps;
+	const int delta_prev = cfra - second_prev;
+	const int delta_next = second_next - cfra;
+	return (delta_prev < delta_next) ? second_prev : second_next;
+}
+
 
 Base *BKE_scene_base_add(Scene *sce, Object *ob)
 {