1 files changed, 9 insertions, 0 deletions
diff --git a/src/common/backend.h b/src/common/backend.h
index c1d878b..c6691eb 100644
--- a/src/common/backend.h
+++ b/src/common/backend.h
@@ -7,12 +7,21 @@ struct yasl_backend_ops;
 
 struct yasl_display {
     const struct yasl_backend_ops *ops;
+    struct yasl_display_cbs callbacks;
 };
 
 struct yasl_surface {
     struct yasl_display *display;
+    struct yasl_surface_cbs callbacks;
+    uint64_t frame_generation;
 };
 
+static inline uint64_t yasl_frame_begin(struct yasl_surface *s)
+{
+    if (++s->frame_generation == 0) ++s->frame_generation;
+    return s->frame_generation;
+}
+
 struct yasl_backend_ops {
     enum yasl_backend type;
     struct yasl_display *(*display_open)(struct yasl_loop *loop, const struct yasl_display_spec *spec);