Exploring Tile-Based Rasterization Alternatives for Mobile Devices

Tile-based rasterization was recently proposed as a solution for en-abling three dimensional computer graphics on low-power mobile devices. In tile-based rasterization the screen is decomposed into independent parts, called tiles, that are processed sequentially by a simple embedded graphics accelerator. By keeping these tiles small, on-chip memory can be used to store intermediate rasterization val-ues. This reduces a major source of power dissipation when com-pared to a conventional graphics pipeline, the external traffic be-tween the rasterization hardware and the framebuffer. In the GRAphics AcceLerator (GRAAL) project a tile-based raster-ization solution utilizing a scenebuffer resident in external memory was proposed. The scenebuffer contains the rasterization instruc-tions needed to process all the screen tiles and is reused for the ras-terization of every tile. Several sorting algorithms were introduced to prevent unnecessary accesses to the graphics accelerator