The PixelFlow Texture and Image Subsystem

Abstract

Texturing and imaging have become essential tasks for high­ speed, high-quality rendering systems. They make possible effects such as photo-textures, environment maps, decals, modulated transparency, shadows, environment maps, and bump maps, to name just a few.These operations all require high-speed access to a large "image" memory closely connected to the rasterizer hardware. The design of such memory systems is challenging because there are many competing constraints: memory bandwidth, memory size, flexibility, and, of course, cost PixelFlow is an experimental hardware architecture designed to support new levels of geometric complexity and to incorporate realistic rendering effects such as programmable shading. This required an extremely flexible and high-performance texture/image subsystem. This paper describes the PixelFlow texture/image subsystem, the design decisions behind it and its advantages and limitations. Future directions are also described.