[clutter] Does it work vertex shader in clutter actor?

Hello. I tried to apply vertex shader with ClutterShader api, but it seems it doesn't draw anything. And I found there is no sample code for vertex shader in tests/interactive/test_shader.c source file, there is only fragment shader test. I'll attach a simple source code for applying vertex

[clutter] VBLANK feature on offscreen

Hi. guys. I have a question about GL vblank syncing mechanism when GL context is offscreen. If composite manager is run, drawing timing is depended by composite manager, so it have no need to wait drawing complete, IMHO There are some implementation about vblank syncing mechanisms in clutter.