Demo of Height-Field Terrain Rendering
                 ======================================

     What This Is
     ~~~~~~~~~~~~
     HEIGHT.ZIP is a demonstration of the height-field rendering graphics
     "engine" I have been working on for the past few months.  For the most
     part I have used it as a test harness to explore the visual results of
     various "speed-up" techniques.  It is not a game (yet), but intended
     to be used in one.

     System Requirements
     ~~~~~~~~~~~~~~~~~~~
        - 386 or 486
        - VGA
        - 5M memory

     Running The Program
     ~~~~~~~~~~~~~~~~~~~
     Use the + and - keys (on the keypad) to increase/decrease speed, and
     the arrow keys to steer.  In addition, the first six Function keys
     have the following actions:

        F1 - Toggle step size (1,2,4).  The "engine" employs a basic
             "ray-casting" algorithm.  Step size is how far to jump between
             locations inspected.

        F2 - Toggle pixel size (1,2,4).  Using ModeX alter the width of the
             pixels being plotted.  The wider the pixel, the fewer columns 
             that have to be plotted.

        F3 - Toggle between maximum distances checked (300,600,900).  Tells
             the program when it can stop "stepping" along the ray.

        F4 - Drawing method (DDA or Fixed-Point).  I originally started
             with a DDA algorithm for calculating each step.  This method
             introduces some distortion, so I tried using a fixed-point
             math technique and was surprized to find that it was almost as
             fast.

        F5 - Toggle between screen layouts (views).  The "engine" is quite
             flexible w.r.t. viewport size and location.

        F6 - Toggle "overhead" map on and between resolutions (1x,2x,4x).

     Status
     ~~~~~~
     The upper left corner of the landscape viewport has the current status
     of the above "toggles" and an indication of the frame rate the engine
     is achieving.

     Landscapes
     ~~~~~~~~~~
     The landscape data included was generated by me.  Height-field data
     (heights.pcx) was created with a home grown fractal technique.  These
     values were then imported into Vista Pro 3.0 where the colour-field
     (colours.pcx) was generated.


     Mike Gardi
     Useful Software

          Voice: (519) 746-2931
            FAX: (519) 746-5972
       Internet: megardi@watserv1.uwaterloo.ca
     CompuServe: 70242,3102
          GEnie: M.Gardi