init

pub fn init(self: *RenderFrontToBack) void {
        const cw = dvui.currentWindow();
        self.* = .{
            .prev_rendering = renderingSet(false),
            .prev_dr_cmds = cw.defer_render_cmds,
            .prev_dr_cmds_after = cw.defer_render_cmds_after,
        };
        cw.defer_render_cmds = &self.render_cmds;
        cw.defer_render_cmds_after = &self.render_cmds_after;
    }