TKTrace Raytracer version 0.001 Alpha 21/06
	
	                 Copyright (C) 1993, Tom Kooij.
	
	                        June 21th, 1993.











	
	1. Introduction

	TKTrace is a raytracer designed innitialy to explore the ins and
	outs of writing a raytracer. I've decided to release this program
	under the GNU public license to allow other people to start
	writing raytracers and/or testing new idea's. 
	
	TKTrace is a 'free' program, please see the license agreement in
	"license.doc" (and "copying") for futher details.
	
	As stated in the license TKTrace you are allowed to use it
	without paying a registration fee to me first. I would, however,
	love to recieve your opinion on this raytracer. And if you signi-
	fically enhance it, I would like to see the results. Just a quick
	email telling how you are, what you do and what you think about
	TKTrace is enough. Postcards are also *very* appreciated. 
	
	Have Fun!
	
	Tom Kooij,
	Schielaan 38b,
	3043 HD Rotterdam,
	The Netherlands.
	
	tomk@interfhq.hacktic.nl
	
	Fidonet: 2:285/800.6 2:285/508.10
	
	2. Things you should know before using TKTrace.
	
	- This raytracer is still under development. Al lot of features
	will have to be added. New primitives (polygons, cones etc) and
	things like solid texturing for example...
	
	- The shader is not complete either (no refraction etc). Coming
	up real soon. (Probably including some exciting idea's by Lex van
	der Sluijs, just wait and see!) 
	
	- Antialiasing has not been implemented yet. (althought the -a
	option appears on the command-line.)
	
	- The parser is terrible. I know. If you can do a better job,
	please go ahead and make us all happy.
	
	3. Using TKTrace

	This is were the real work starts. I haven't had the time to
	write this section *yet* (In fact, if I'd had the time, I would
	have used it to improve the raytracer, not the docs :-) )
	
	3.1 Coordinate System
	
	TKTrace uses the right-handed coordinate system; this means that
	the positive-x-axis points to the right, the positive-y-axis
	points into the screen and the positive-z-axis points upwards. 
	
	3.2 Scene description format
	
	The scene description was originally derived from the NFF-format
	by Eric Haines

	3.2.1 Viewpoint

	viewpoint                /* no particular order */
	     {
	     from x y z          /* look from */
	     at x y z            /* look at */
	     up x y z            /* up vector */
	     angle a             /* view-angle */
	     aspect a            /* aspect-ratio of image */
	     resolution x y      /* resolution of image */ 
	     background r g b    /* background color */
	     }
	
	3.2.2 Lights
	
	light 
	     { 
	     x y z     /* location */
	     r g b     /* color (brightness) */
	     } 
	
	3.2.2 Surfaces
	
	surface 
	     {
	     r g b     /* ambient lighting */
	     r g b     /* diffuse reflection */
	     r g b     /* specular reflection */
	     s         /* phong highlight */
	     }
	
	3.2.3 Spheres
	
	sphere
	     {
	     x y z     /* location */
	     r         /* radius */
	     }
	
	3.2.4 Planes
	
	plane
	     {
	     dx dy dz  /* direction vector */
	     d         /* distance from normal */
	     }
	
	3.2.5 Quadrics
	
	quadric
	     { 
	     a b c     /* ax^2 + by^2 + cz^2 +        */
	     d e f     /* dxy  + exz  + fyz  +        */
	     g h i j   /* gx   + hy   + iz   +  j = 0 */
	     }
	
	3.2.6 Abbreviations
	
	background     b
	light          l
	plane          p
	quadric        q
	sphere         s
	viewpoint      v
	surface        f
	
	
	4. If you want to enhance TKTrace
	
	 - Join the dutch fidonet 'FRACTAL.028' echo, if you can.
	 - e-mail/netmail me.
	 - try to obtain the latest version.
	
	I'll try to coordinate development. Please get in touch with me
	before you start hacking.
	
	
	5. Credits & Bibliography
	
	TKTrace was modeled closely after the MTV-raytracer by Mark
	VandeWettering.
	
	The following books have been helpful during the development of
	TKTrace:
	
	     An Introduction to Raytracing
	     Edited by Andrew S. Glassner
	     Academic Press 
	     1989
	
	     Computer Graphics: Principles and Practice. 2nd Edition
	     James D. Foley et al
	     Addison-Wesley
	     1990
	
	     Photorealism and Ray Tracing in C
	     Christopher D. Watkins et al
	     M&T
	     1992