Fast spheres, shadows, textures, transparencies, and imgage enhancements in pixel-planes

Abstract

Pixel-planes is a logic-enhanced memory system for raster graphics and imaging. Although each pixel-memory is enhanced with a one-bit ALU, the system's real power comes from a tree of one-bit adders that can evaluate linear expressions Az + By + C for every pLxel (z, y) simultaneously, as fast as the ALUs and the memory circuits can accept the results. We and others have begun to develop a variety of algorithms that exploit this fast linear expression evaluation capability. In this paper we report some of those results. Illustrated in this paper is a sample image from a small working prototype of the Pixel-planes hardware and a variety of images from simulations of a full-scMe system. Timing estimates indicate that 30,000 smooth shaded triangles can be generated per second, or 21,000 smooth-shaded and shadowed triangles can be generated per second, or over 25,000 shaded spheres can be generated per second. Image-enhancement by adaptive histogram equalization can be performed within 4 seconds on a 512x512 image.

Computing shortest path maps with GPU shaders

“…Algorithms for rendering hard shadows in real time can be roughly sorted into three categories: shadow mapping [Williams 1978;Lauritzen et al 2011;Lloyd et al 2008], alias-free shadow maps [Aila and Laine 2004;Johnson et al 2005;Sintorn et al 2011], and shadow volumes [Fuchs et al 1985;Heidmann 1991]. Our work relies on the generation of shadow volumes with a variation of the z-fail approach [Carmack 2000;Bilodeau and Songy 1999;Everitt and Kilgard 2002].…”

Surface based anti-aliasing

“…In practice this can be done by either computing N color samples per pixel or by rendering the scene in multiple passes with different subpixel offsets and accumulating the result [Fuchs et al 1985;Deering et al 1988;Mammen 1989;Haeberli and Akeley 1990].…”

Embedded function composition

“…Alternatively, Pixel Planes was devised as a special purpose rasterizer which was later discovered to have hidden flexibility [Fuchs et al 1985]. Pixel Planes' core element was a parallel linear expression evaluator distributed throughout frame memory.…”