THIS IS A DESCRIPTION OF THE PARAMETERS TO THE ROUTINE SHADE.
------------------------------------------------------------

illum_parm_td illum;     
	         the illumination parameter structure for the current object
lght_parm_td  *light;
	         The light parameter structure light[i] is for object i
viewport_td   view_p;
		 The viewport structure (vb,vt,vr,vl)
tran_mat_td   inv_view
	         The inverse of the viewing transformation (takes you back to
	 	 world space
tran_mat_td   inv_tm;
	         The inverse of all the transformations - takes you back to
		 object space.
double        z, y_coord 
		 The z and y coordinates of this pixel in perspectedd image
	         space  (-1.0 to 1.0)
long          x; 
        	 The x location of the pixel in screen space.
int           l_interp
		 Interpolate light vectors per pixel ?
int            numlights 
		 the number of lights for the scene
int            face
		 The face number of the polygon covering this pixel
		 that is being processed
c_t_illum_td  cooke;
		 Cooke-Torrence illumination structure.
txt_u_td      *u_map;
txt_v_td      *v_map;   
		 Some texture inverse mapping values - NOT USED for 782
xyz_td        **face_ptr2
                 A structure containing the points in object space
	         face_ptr[face][0,1,2,3] are the points you will need for
	         texturing.
xyz_td         norm_p 
		 The normal in world space - used for illumination
		 calculation
xyzw_td       **wld_sp;
		 The structure containig the points in world space -
		 used for environmental mapping and "bump" mapping.
rgb_td        color_buffer
		The color value currently in the color buffer for this
		pixel - used for transparency calculations.


THIS IS A DESCRIPTION OF THE LOCAL VARIABLES OF THE ROUTINE SHADE.
------------------------------------------------------------------

double         xt;
 		 A temporary variable used for getting the x location
		 of the pixel in perspected image space.
xyz_td         pnt_img,
		 The location of the point in image space.
xyz_td         pnt_obj,
                 The location of the current pixel in object space.
xyz_td         pert_norm,
                 The normal in world space used for illum. calcs
xyz_td         reflect;
		 A reflection vector for env. mapping
xyzw_td        pnt_objw;
                 Temp variable used to get the point in object space.
rgb_td         final_color, diffuse, specular, temp, env_spec;
		 Color values used in calculating the color of the
		 pixel.

Note: When doing color texturing, you can put the value from the color
texture map in illum.color[face], since nothing is stored in this when
the object is color textured.

David
-----