A system to apply a smoothing filter during anti-aliasing at a post-rendering stage. An embodiment of the system includes a three-dimensional renderer, an edge detector, and a smoothing filter. The three-dimensional renderer is configured to render a three-dimensional scene. The edge detector is coupled to the three-dimensional renderer. The edge detector is configured to read values of a depth buffer and to apply edge detection criteria to the values of the depth buffer in order to detect an object edge within the three -dimensional scene. The smoothing filter coupled to the edge detector. The smoothing filter is configured to read values of a color buffer and to apply a smoothing coefficient to the values of the color buffer. The values of the color buffer include a pixel sample at the detected object edge.