o This program is based on Eric Chen's code in Graphics Gems II
  (http://www1.acm.org/pubs/tog/GraphicsGems/gemsii/radiosity/).
  The following changes have been made:

1. Form factor calculation is moved to a new file ffactors.c.
2. OpenGL code is added to draw.c
3. TView::near and far are changed to nearP and farP.
4. Room.h is created to make roomPolys[] accessible to the
   other modules, especially rad.c, in order to interpolate
   the colors of elements.

CHANGES RELATED TO THE MESHING ARTIFACTS
----------------------------------------
The original version display the elements as flat-shaded polygons.  That is good
for visualizing the meshes, but not very visually pleasing.

In order to remove those meshing artifacts, we need to assign different color to
each vertice of elements and display the elements as smooth shaded polygons.  That
requires at least the following changes:

draw.c:
	RunApp(): change to glShadeModel(GL_SMOOTH).
	Add DrawShadedPolygon()

room.c:
	We must make the following accessible by the other modules:
	(This is why I added room.h.)
		typedef TQuad
		#define numberOfPolys
		roomPolys[]

rad.c:
	We must associate a color to each element vertex.  Its color may be
	interpolated from the neighboring 1, 2, or 4 elements.
