I was wondering if it is possible to modify Gamemaker's general shader to use a z variable in addition to the already-present x and y variables. If so, how would this be done? Through the pixel or vertex shader? What shader code would have to be written? Would it automatically use the z var, or would that have to be done in another shader? What would that other shader or script look like? Could I also have the shader automatically render shadows? I use Gamemaker Studio 1.4, or whatever version the original is at.