Introduction to XRay
                                 Version 1.0

                                  Written by
                Christian Schnell     and     Max Vogelbusch
              lulli@cs.tu-berlin.de         max@cs.tu-berlin.de

             WWW: http://www.cs.tu-berlin.de/~lulli/xray/xray.html



                             About this document
                             ~~~~~~~~~~~~~~~~~~~
This is just a small introduction to XRay, but this should be enough to get 
started, check out the sample-scenes if you have trouble, they should cover 
all of it.
Try to access the WWW-Homepage of XRay, there will be the latest update 
and infos.

NOTE: Expressions with a leading '->' are defined in this document.


                                 Installation
                                 ~~~~~~~~~~~~
All you need additionaly to xray.zip ist CTL3D.DLL, you can get it at many 
ftp-sites but almost everybody should have it installed already. 
Just copy the binaries to some directory and that is it !


                                     Usage
                                     ~~~~~
The Dos-Version prints out its parameters when you start it without
parameters, there should not be a problem for you to understand how it works.

In Windows, you have access to a whole lot of parameters, here is a brief 
description of every window and its parameters:

The Main Window:
~~~~~~~~~~~~~~~~
The Main Window is just a bar with a simple menu:

Project: To create, open, save and delete a scene.
Editor : Opens a new ->Editor window
Tracer : Opens a new ->Tracer window
Exit   : Quit XRay

The Editor Window:
~~~~~~~~~~~~~~~~~~
The menu:
Object : Insert:           Insert a sphere, plane, quadric, tube or light.
         Delete/Load/Save: Object
         Parameter:        Set object-specific parameters
         Texture:          Set object-texture
         Boolean:          Boolean functions, caution: bugs.
Options: Perspective:      XY, ZY and XZ are standard-perspectives.
                           Z Division off means parallel projection.
         
Select and drag objects with the left mousebutton, use the right one for 
a popup-version of the Objects-Menu.

The Tracer Window:
~~~~~~~~~~~~~~~~~~
The Tracer Window holds the output of the tracer. 
The menu:
Trace:   Start the tracing process
Stop:    Stop it
Save:    Save Picture
Close:   Close Tracer Window

The Texture Window:
~~~~~~~~~~~~~~~~~~~
To generate a texture, select a ->Function, a ->Colortable and set the 
parameters. The ->Function is the solid texture-function which is used to 
determine the 'strength' of a given (x,y,z). This strenght is then used as 
an index into the ->Colortable. Additionaly, ->Distortion will distorte your
selected ->Function using Noise or Turbulence.

Modifies - Color / Normal              Not implemented
Colortable Button                      Opens an ->Colortable Window
Function                               Solid Texture Function
Reflection                             Yeah
Refraction                             not yet
Distortion                             Opens an ->Distortion Window
Ambient                                General illumination
Difuse                                 Illumination from lightsource
Wideness                               Determines the the maximum angle for
                                       relevant lightsource-rays.
Phong                                  Hilight on object
Ph-Wide                                ->Wideness information for Phong

The Colortable Window:
~~~~~~~~~~~~~~~~~~~~~~
A Colortable sets the color for a texture ->Function. 

This is what the Colortable Window roughly looks like:

      +---------------------------------------+
      | +-------------------+     RED   (h)   |
      | | (a) Coloritems    |     GREEN (i)   |
      | +-------------------+     BLUE  (j)   |
      | +-------------------+     ALPHA (k)   |
      | | (b) Transparency  |                 |
      | +-------------------+                 |
      | +-----+ +------------+                |
      | |Color| | MOVE   (e) |   MIX      NEW |
      | | (c) | | INSERT (f) |   LOAD    SAVE |
      | |     | | DELETE (g) |   CANCEL    OK |
      | +-----+ +------------+                |
      +---------------------------------------+

A colortable is made up out of a couple of coloritems.

In (a) you have the general overwiev of your colortable. The small bar under 
(a) (not shown in the scheme above !) shows the position of the coloritems, 
this is also where you move a coloritem if (e) is selected. To add a new 
coloritem, select (f) and click in the small bar under (a) to set the 
position for the new item. To delete an item, select (g) and then select the 
item which you want to delete.

Each coloritem has a red, green, blue and alpha portion (alpha is 
transparency). Set the color either by hand in (h), (i), (j) and (k) or 
klick on the MIX-Button to get the standart Windows-Color-Requester. 
Use the small bar under (b) to set alpha with the mouse.

The Distortion Window
~~~~~~~~~~~~~~~~~~~~~
The Distortion Window is to set the parameters for additional distortion of 
your selected ->Texture-Function. This can either be Noise or Turbulence, 
Play with the distortion option, you can produce wild effects with this one.
The wood texture for example makes sense only in combination with distortion.