Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site arizona.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!utah-cs!arizona!rogerh From: rogerh@arizona.UUCP (Roger Hayes) Newsgroups: net.graphics Subject: Dithering and a project Message-ID: <16648@arizona.UUCP> Date: Wed, 17-Oct-84 23:59:42 EDT Article-I.D.: arizona.16648 Posted: Wed Oct 17 23:59:42 1984 Date-Received: Fri, 19-Oct-84 01:52:19 EDT References: <1556@ucla-cs.ARPA> Organization: Dept of CS, U of Arizona, Tucson Lines: 21 On the 24-to-8 issue: dithering is quite simple and produces good results. The technique can be derived starting from the 2 pages in Foley and Van Dam. I usually dither to 3-3-2 bits (rgb) when I have an 8-bit frame buffer -- does anyone take the trouble to divide the target color space evenly? On another issue -- I need a pointer to literature on incremental (ie, generalized Bresenham) techniques for drawing quadratic curves. I have a raycaster working (arbitrary quadric shapes, boolean combinations), but it's deathly slow. To speed it up, I would like to use the information from one ray to determine the next; I need a quick way to determine the solution for z of A*z^2 + B*z*x + C*z + D*x^2 + E*x + F >= 0 at (x+1), given the solution at x. "Quick" means faster than substituting the new x value and solving directly. Roger Hayes University of Arizona rogerh%Arizona@csnet-relay.CSNET {ihnp4, decvax, ucbvax}!arizona!rogerh by UUCP