SPARP: a single pass antialiased rasterization processor

Abstract

We present a rasterization processor architecture named SPARP (single-pass antialiased rasterization processor), which exploits antialiased rendering in a single pass. Our architecture is basically based on the A-buffer (Carpenter, Computer graphics 1985;19:69–78) algorithm. We have modified the A-buffer algorithm to enhance the efficiency of hardware implementation and quality of the image rendered, such as the data structure of pixel storage elements, the merging scheme of partial-coverage pixels, and the blending of partial-coverage or non-opaque pixels. For the scan conversion and generation of subpixel masks, we use the representation of edges that was proposed by Schilling (Computer graphics 1991;25:131–41). We represent partial-coverage pixels for a pixel location by a front-to-back sorted list as in the A-buffer and dynamically manage the list storage. We have devised a dynamic memory management scheme that extremely simplifies the memory managing overheads so that we can build it by hard-wired logic circuitry. In our architecture we can render an antialiased scene with the same rendering context of Z-buffer method. Depending on the scene complexity, proposed architecture requires rasterization time 1.4–1.7 times as much as a Z-buffer rasterizer does. The buffer memory requirements can vary depending on the scene complexity; the average storage requirement is 2.75 times that of the Z-buffer for our example scenes. Our architecture can be used with most rendering algorithms to produce high-quality antialiased images at the minimally increased rendering time and buffer memory cost, but due to the improvements in semiconductor technology we can expect that antialiased rasterization processors will be widely adopted in the near future.