Fix fullscreen menu flash when we do a context reset/fullscreen toggle

Author: LibretroAdmin

command.c

@@ -2529,6 +2529,59 @@ void command_event_reinit(const int flags)
       video_st->frame_cache_width  = cached_snapshot_w;
       video_st->frame_cache_height = cached_snapshot_h;
       video_st->frame_cache_pitch  = cached_snapshot_p;
+
+#ifdef HAVE_MENU
+      /* If the menu is alive across the reinit, the runloop's
+       * pre-frame menu work (driver_ctx->render +
+       * set_texture_enable) doesn't get a chance to run before
+       * the cached_frame() replay below.  Two consequences if we
+       * don't reproduce that work here:
+       *
+       * 1. The new video driver instance starts with its
+       *    menu-texture flag (D3D11_ST_FLAG_MENU_ENABLE,
+       *    GL2_FLAG_MENU_TEXTURE_ENABLE, etc.) cleared, so the
+       *    replay frame falls into the driver's "else if
+       *    (statistics_show)" branch and draws OSD stats on the
+       *    bare core framebuffer instead of the menu overlay.
+       *
+       * 2. Menu drivers like ozone cache layout/font dimensions
+       *    keyed on the previous viewport size and only
+       *    recompute them when their render() callback notices a
+       *    width/height change.  If we replay before render()
+       *    runs, the menu draws at the old (windowed) scale into
+       *    the new (fullscreen) viewport, so fonts and widgets
+       *    appear undersized for one frame until the next
+       *    runloop iteration corrects them.
+       *
+       * Mirroring the runloop's pre-frame menu sequence here --
+       * render with the new dimensions, then raise the
+       * texture-enable flag -- keeps the snapshot replay
+       * visually consistent with subsequent frames.
+       *
+       * Gated on a valid snapshot: without one we won't be
+       * pushing a replay frame anyway, and calling render() on a
+       * freshly-(re)initialised menu driver before the runloop
+       * has had a chance to populate it can leave it in a
+       * partially-computed state for the next real frame
+       * (e.g. ozone clears OZONE_FLAG_NEED_COMPUTE after a
+       * premature render). */
+      if (menu_st->flags & MENU_ST_FLAG_ALIVE)
+      {
+         if (     menu_st->driver_ctx
+               && menu_st->driver_ctx->render)
+            menu_st->driver_ctx->render(
+                  menu_st->userdata,
+                  video_st->width,
+                  video_st->height,
+                  false);
+
+         if (     video_st->poke
+               && video_st->poke->set_texture_enable)
+            video_st->poke->set_texture_enable(video_st->data,
+                  true, false);
+      }
+#endif
+
       video_driver_cached_frame();
    }