Method and apparatus for sampling on a non-power-of-two pixel grid

摘要

The embodiments of the present invention are a method and apparatus to perform anti-aliasing using multi-sampling on a non-power-of-two pixel grid. Using the present invention with 6 sample multisampling gives the same visual antialiasing quality as 8 samples using a prior art technique but uses less memory. A non-power-of-two equally spaced sample from a conventional grid of size NxN, where N is 12 can be chosen using the present invention. A scan conversion to determine the set of pixels covered by a polygon is performed in two parts. According to one embodiment, the present invention can multiply and divide by "N" in order to multisample an image using samples per pixel chosen from a NxN sub-sample grid, where "N" is not necessarily a power of 2. The present invention performs the divide by "N" step, where the step is achieved using a quick divide by 3 or 12 technique.