if (shader_enabled)
{
    if (!surface_exists(surf_recolour))
        surf_recolour = surface_create(surface_get_width(application_surface), surface_get_height(application_surface));
    surface_set_target(surf_recolour);
    draw_clear_alpha(c_black, 1);
    gpu_set_colorwriteenable(true, true, true, false);
    if (global.darkzone != 1)
        draw_surface_ext(application_surface, 0, 0, 0.5, 0.5, 0, c_white, 1);
    else
        draw_surface_ext(application_surface, 0, 0, 1, 1, 0, c_white, 1);
    gpu_set_colorwriteenable(true, true, true, true);
    surface_reset_target();
    pal_swap_set(1493, 1);
    draw_surface(surf_recolour, camerax(), cameray());
    pal_swap_reset();
}