procedure sbcpln

This subroutine plots a diffusively-lit, semi-transparent, coloured plane through a unit cell. 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 all the lattice-vertices should be negative; the viewing-screen is fixed at z=0.

Syntax
sbcpln EYE,LATICE,IC1,IC2,LIGHT,SLNORM,APOINT,ICEDGE,ITRANS

Arguments
ARGUMENT    TYPE I/O DIMENSION DESCRIPTION
EYE:   R*4 I 3 (x,y,z) coordinate of eye-position.
LATICE:   R*4 I 3 x 4 (x,y,z) coordinates of the origin
   and the a, b & C lattice-vertices.
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.
SLNORM:   R*4 I 3 (x,y,z) direction of normal to plane.
APONIT:   R*4 I 3 (x,y,z) coordinate of a point within
   the plane.
ICEDGE:   I*4 I - If >=0, it's the colour-index for
   the boundary of the plane.
ITRANS:   I*4 I - Level of transparency:
   0 = 0%; 1 = 25%; 2 = 50%; 3 = 75%.