------------------------------------------------------------------------------
LIGHTS:
------------------------------------------------------------------------------
lgtobj = Nnew_light  /*returns handle to new light or -1 if all lights have
		      already been used */

/* set light attributes */
<lgtobj> set_ambient r g b
	set_color r g b
	set_position x y z local
        switch on|off

/* turn ALL lights on/off */
Nlights on|off


------------------------------------------------------------------------------
DRAWING:
------------------------------------------------------------------------------
/*clear screen with background color 'color' or default bg color*/
Nclear [color]     
Nset_draw front|back|both /*buffers*/
Ndraw_model               /*draw lighting sphere */
Ndraw_X x y               /* x &y floats in real world coords */
Ndraw_line_on_surf  x1 y1 x2 y2    /* x1, y1, x2, y2 floats in world coords */
Ndraw_wire id

Nquick_draw      /* draw all surfaces in wireframe */
Nsurf_draw_all
Nvect_draw_all
Nsite_draw_all

write_rgb filename	  /* write current contents of drawing win to file */
Nset_background

------------------------------------------------------------------------------
MAP OBJECTS:
------------------------------------------------------------------------------
note: type = surf|site|vect
      att = topo|color|mask|transp|shine|emit
map_obj = Nnew_map_obj type [filename] /*returns handle to new object of type 'type' */
n = Nnum_map_obj type /* how many of type 'type'? */

<map_obj> delete   /* delete map_obj */
	draw     /* draw map_obj with current draw modes & color */
	NOTE: xtrans, ytrans, ztrans in map units
	get_trans    /* returns: {xtrans ytrans ztrans} */
	set_trans xtrans ytrans ztrans

	/*the following options are only appropriate if map_obj is type surf */

	get_exag_guess /* returns: guess (approx exag for init value)*/
	set_exag       /* sets exag value for this map_obj *?
	set_drawmode poly|wire|wire_poly
	get_res  wire|poly|both  /*returns {xres yres [xres2 yres2]} */
	set_res  wire|poly|both   xres yres [xres2 yres2]
	set_wirecolor 0xaabbggrr
	set_att att 'constant'|filename [value]
	unset_att att
        set_nozero att 0|1  /* att = color or topo */

	/*the following are only appropriate if map_obj is type vect or site*/

	/*select/unselect surface with which vect or site is associated */
	select_surf sfid
	surf_is_selected sfid
	unselect_surf  sfid

	/* color & width for either vect or site, last 4 site only */
	/* useatt = z|color|0 where attribute value of site file is used  */
	/* either as height or color of marker or not at all. 0 is default */
	set_mode color width [size marker useatt] 


is_masked x y /* returns 0|1 */
------------------------------------------------------------------------------
MOVEMENT & LOCATION:
------------------------------------------------------------------------------

{x y z} = get_to
{x y z} = get_from
look_here sx sy  /* set focus to where screen x & y point */
set_focus_map [id] /* if no id sets no focus */
moveto x y z       /* change viewer position */

set_fov fov

{n s e w} = get_region

/* given screen x & y, returns point & surfaceto which mouse is pointing */
{x y z id} = get_pt_on_surf sx sy 

dim = get_longdim /* XYrange: used to compute appropriate default height */
{min max} = get_zrange [doexag] [nz]
{min max mid} = get_zextents id /* zrange for a single map */

/* global exageration */
exag = get_exag
set_exag exag 


------------------------------------------------------------------------------
CUTTING PLANES:
------------------------------------------------------------------------------
plane_obj = Nnew_cutplane_obj id_num /* up to six */
plane_obj draw [surf1 surf2] /* if surfs specified only draws btwn s1 & s2 */
      	on
      	off
	set_rot dx dy dz
	set_trans dx dy dz

-----------------------------------------------------------------------
COMPOSITE (i.e. tcl procs for widget callbacks)
-----------------------------------------------------------------------
set_persp persp
set_xy x y    	/*viewer position */
set_height hgt  /*viewer position */

draw_all

/* window is resized or exposed */
resize
expose