A directionally adaptive edge anti-aliasing filter

Figure 1: Steps of the Directionally Adaptive Edge Anti-Aliasing Filter algorithm. The left frame shows geometry edge pixels in the scene determined from the hardware MSAA samples. The center frame represents the gradients at the pixels to be filtered. The right frame is the final image where filtered colors for the pixels in the center image are derived using MSAA samples from a neighborhood of 3x3 pixels and 72 subsample values. (Images generated from Futuremark 3DMark03.) The latest generation of graphics hardware provides direct access to multisample anti-aliasing (MSAA) rendering data. By taking advantage of these existing pixel subsample values, an intelligent reconstruction filter can be computed using programmable GPU shader units. This paper describes an adaptive anti-aliasing (AA) filter for real-time rendering on the GPU. Improved quality is achieved by using information from neighboring pixel samples to compute both an approximation of the gradient of primitive edges and the final pixel color.