1. A method for rendering, comprising the steps of: testing each pixel in a set of pixels to determine if each said pixel is part of an object to be displayed; changing at least one bit of each of said pixel to indicate the result of said testing step for that pixel; performing a filtering operation on each pixel according to said result; removing at least some of said pixels from said set of pixels according to the result of said filtering operation; blending said set of pixels with an image data; wherein said changing step includes setting an alpha value of each pixel that fails said testing step to zero.