bgfx_sys::BGFX_STATE_BLEND_FUNC_RT_x!

macro_rules! BGFX_STATE_BLEND_FUNC_RT_x {
    ($src:expr, $dst:expr) => (
        (($src >> bgfx_sys::BGFX_STATE_BLEND_SHIFT) as u32) | ((($dst >> bgfx_sys::BGFX_STATE_BLEND_SHIFT) as u32) << 4)
    );
}