Spróbuj może z tym:
GML
draw_set_blend_mode(bm_subtract);
{
with(oLight)
{
if( visible ) // +
draw_sprite_ext(spr, 0, x-view_xview[0], y-view_yview[0], sclX, sclY, dir, make_color_rgb(alpha*255, alpha*255, alpha*255), 1);
}
}
draw_set_blend_mode(bm_normal);