I'm incorporating a day/night cycle in my game. The way I have it set up is that, when it's sunset, a black rectangle at .75 opacity starts to move across the screen from the left until it covers the entire room, like how sunlight would work in an actual sunset. Think of it like a wall of darkness closing in. This is cool and all, but in order for it to be more realistic, the rectangle shouldn't all be one shade. The closer to the light it is, the lighter the shadow, right? So, what I'm wanting is to have the rectangle blend from an opacity of 0 right where the light touches to an opacity of .75 deep inside the shadow. Is this possible? I am using draw_set_alpha. EDIT: The rectangle is being drawn. It is not an object.