1. A method for reducing the number of sample points tested for rendering a screen space tile of an image, the method comprising: constructing a trajectory of a primitive extending within an image which is to be rendered, the screen space tile including a plurality of sample points distributed thereover; determining low and high bounds in a non-screen space dimension for the screen space tile of the image which is to be rendered by using points of the trajectory of the primitive; constructing a bounding volume for the screen space tile of the image by using the low and high bounds in the non-screen space dimension for the screen space tile, wherein the bounding volume includes a first dimension that extends between the low and high bounds in the non-screen space dimension that are defined as a function of the trajectory of the primitive, and wherein the bounding volume overlaps a portion of the screen space tile; and excluding from testing, one or more sample points which are located within the screen space tile, and which are not overlapped by the bounding volume.