1. A method for displaying graphical images, the method comprising: receiving first vertices defining a first triangle; (a) computing a first octant identifier word for a first edge of the first triangle (b) computing a second octant identifier word for a second edge of the first triangle; (c) determining a first orientation for the first triangle using the first octant identifier word and the second octant identifier word; (d) performing rendering computations on the first triangle in response to the first orientation equaling a rendering orientation value, wherein results of said rendering computations are usable to form an image on a display device.