_________________________ESDEMO by ERIC SCHMIDT__________October.1.1996______
_____________________________________________________________________________


INTRODUCTION:

     The purpose of this demo is to present a cross-section of my graphics
     and animation programming skills.  I have applied many of today's
     standard rendering techniques as well as my artistic ability and design.

     The graphics library used to create this demo was hand crafted from
     scratch over the months of July-September 1996 using C/C++.



REQUIREMENTS:

     * Pentium-586 133MHz or better recommended.  A 486 will do.

     * VGA mode 0013h (320x200x256) compatibility and
       VESA VBE v1.2 mode 0112h (640x480x16.7M) compatibility

     * 4MB of free RAM

     * 3MB of free hard disk space

     * MS-DOS 6.2 or higher or Windows95

     * DPMI host
      (ESDEMO.EXE will demonstrate optimal performance under MS-DOS.
       If you do not have a DPMI server installed in DOS, the demo will
       function under Windows95 which has built-in DPMI.  ESDEMO.PIF is
       provided to force a full screen upon execution in Windows95.)



TO RUN:

     ESCHMIDT.ZIP =
      { ESDEMO.EXE , ESDEMO.PIF , ESDEMO.DAT , README.TXT(this file) }

     Unzip the contents of ESCHMIDT.ZIP into a directory on a hard
     disk.  Then simply enter ESDEMO at the DOS prompt while inside
     that directory -or- double click the ESDEMO application icon
     in Windows95.



TECHNIQUES USED IN THE DEMO:

  ANIMATED PHONG-SHADED TEXTURE-MAPPED TORUS

     The first phase of the demo features an animated torus.  As with
     all of the animation in this demo, Hermite cubic polynomials are
     used for interpolating object location and B-spline-interpolated
     quaternion numbers are used for object rotation.

     The torus is more than just texture mapped -- it is 'light sourced'
     using the Phong reflectance model with Phong interpolation.  Since
     this is done with only 256 colors, special care is needed to
     construct a suitable color-map.

     Here, a single "Warn's spotlight" light source is used.

     The actual texture used here is derived from the following...


  2D GRAPHIC ART, HAND-DRAWN PIXEL BY PIXEL

     A standard 'paint' program was used to draw this image into the
     computer.  It was from a drawing on textured board that I did in
     1993.  No Scanners were used!  The process of converting my art
     to a pixmap took approximately 40 hours of mouse clicking.


  ANIMATED TRILINEAR-INTERPOLATED PERSPECTIVE-CORRECTED MIP-MAPPED CUBE

     The above mentioned 24-bit pixmap is decomposed by the demo and
     converted into an 8-bit texture with a suitable 256-colormap.
     Prefiltered mip mapping arrays are then calculated.

     The cube is made up of six "large" polygons.  At any given time, at
     least three of them are 'back facing' and are therefore ignored by the
     scanning routine.  The front facing polygons are scanned using
     trilinear interpolated mip mapping with perspective correction.

     My perspective correcting routine uses hyperbolic interpolation to
     display large texture-mapped polygons accurately.  (i.e. No 'fake-it'
     methods are used.)


  RAY-TRACED SCENE NUMBER ONE

     The 24-bit image makes another appearance -- This time it tiles the
     XY-plane.  Actually, 24-bit trilinear-interpolated mip map arrays of
     the image were used to reduce the aliasing that can arise at the
     horizon.  Another technique to reduce aliasing in general was used:
     super-sampling.  For each screen pixel, 16 distributed rays were
     shot into the scene from the center of projection and their average
     returned intensity was computed.

     For each ray shot into the scene, if it makes contact with an object,
     a reflected ray is computed and then recursively traced.  "Shadow
     feelers" are also shot out from an intersection point to each of the
     two "Warn's spotlights" to see if the intersection point lies in some
     object's shadow.

     If the object intersected is transparent, a transmitted ray is
     calculated and recursively traced as well. For the transparent
     cube in the scene, I used a refractive index of 1.15.


  ANIMATED GOURAUD-SHADED TORUS AND TWIST

     The torus and an interesting shape I call the 'twist' are animated
     and rendered using the Phong reflectance model with Gouraud
     interpolation.

     There are two "Warn's spotlight" light sources in this animation.

     Z-buffering is demonstrated here also.


  RAY-TRACED SCENE NUMBER TWO

     The purpose of this scene is to demonstrate transparency in objects
     that are more complex than the cube.  Both the torus and the twist
     were given refractive indexes of 1.15.  The surface of the glass twist
     is made up of 360 distinct triangles.


_____________________________________________________________________________
_____________________________________________________________________________

                                Eric Schmidt
                            18571 Westbrook Drive
                           Livonia, Michigan 48152

                               (810) 615 0030

                            eschmidt@oeonline.com
_____________________________________________________________________________
_____________________________________________________________________________