procedure sbcone

This subroutine plots a diffusively-shaded coloured right-angular cone. All (x,y,z) values are taken to be given in world coordinates. The z-component of the eye-poisition should be positive and that of the base and appex of the cone should be negative (< -radius); the viewing-screen is fixed at z=0.

Syntax
sbcone EYE,BASE,APEX,RADIUS,IC1,IC2,LIGHT,NSIDES

Arguments

ARGUMENT    TYPE I/O DIMENSION DESCRIPTION

EYE:   R*4 I 3 (x,y,z) coordinate of eye-position.

BASE:   R*4 I 3 (x,y,z) coordinate of the centre of

   the base of the cone.

APEX:   R*4 I 3 (x,y,z) coordinate of the apex.

RADIUS:   R*4 I - Radius of the base of the cone.

IC1,IC2:   I*4 I - Lowest & highest colour-index to be

   used for the shading.

LIGHT:   R*4 I 3 (x,y,z) direction of flood-light.

NSIDES:   I*4 I - The order of the polygon to be used

   for the cross-section of the cone.

ARGUMENT	TYPE I/O DIMENSION DESCRIPTION
EYE:	R*4 I 3 (x,y,z) coordinate of eye-position.
BASE:	R*4 I 3 (x,y,z) coordinate of the centre of
	the base of the cone.
APEX:	R*4 I 3 (x,y,z) coordinate of the apex.
RADIUS:	R*4 I - Radius of the base of the cone.
IC1,IC2:	I*4 I - Lowest & highest colour-index to be
	used for the shading.
LIGHT:	R*4 I 3 (x,y,z) direction of flood-light.
NSIDES:	I*4 I - The order of the polygon to be used
	for the cross-section of the cone.