Ruby Structs and floats required in place of Array in ruby-opengl

I can't think that I'm the only person that has encountered this, but neither have I found any references to the issue (or clues in the distribution).
I have recently been playing with ruby1.9-opengl bindings, and I have found the following issues:-

1. Ruby Strings are no longer accepted (to give window title), my solution is to replace String with an empty array anything else (including no entry) seems to be interpreted as a String (input needs to be a CString, ie an array of C chars or possibly pointer thereof).

2. Properties such as color and position, in the Red Book and other examples (included with the source download) are given as an Array. When I've tried to run these examples, I get error messages that a Struct is required not an Array (see below for my coding of Struct to replace Array the name of the Struct and symbols chosen for the Struct variable is unimportant). Parameter Arrays with single float item seem to require a float replacement.


#
# Copyright (c) Mark J. Kilgard, 1994.
#
# (c) Copyright 1993, Silicon Graphics, Inc.
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# any purpose and without fee is hereby granted, provided that the above
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# the name of Silicon Graphics, Inc. not be used in advertising
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# written prior permission.
#
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# AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
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# ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
# POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
#
# US Government Users Restricted Rights
# Use, duplication, or disclosure by the Government is subject to
# restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
# (c)(1)(ii) of the Rights in Technical Data and Computer Software
# clause at DFARS 252.227-7013 and/or in similar or successor
# clauses in the FAR or the DOD or NASA FAR Supplement.
# Unpublished-- rights reserved under the copyright laws of the
# United States.  Contractor/manufacturer is Silicon Graphics,
# Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
#
# OpenGL(TM) is a trademark of Silicon Graphics, Inc.
#
# material.c
# This program demonstrates the use of the GL lighting model.
# Several objects are drawn using different material characteristics.
# A single light source illuminates the objects.
require 'opengl'
include Gl,Glu,Glut

Properties = Struct.new("Properties", :a, :b, :c, :d)

# Initialize z-buffer, projection matrix, light source,
# and lighting model.  Do not specify a material property here.
def myinit
        ambient = Properties.new(0.0, 0.0, 0.0, 1.0 )
        diffuse = Properties.new(1.0, 1.0, 1.0, 1.0)
        position = Properties.new(0.0, 3.0, 2.0, 0.0)
        lmodel_ambient = Properties.new(0.4, 0.4, 0.4, 1.0)
        local_view = 0.0
  
        glEnable(GL_DEPTH_TEST)
        glDepthFunc(GL_LESS)
  
        glLight(GL_LIGHT0, GL_AMBIENT, ambient)
        glLight(GL_LIGHT0, GL_DIFFUSE, diffuse)
        glLight(GL_LIGHT0, GL_POSITION, position)
        glLightModel(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient)
        glLightModel(GL_LIGHT_MODEL_LOCAL_VIEWER, local_view)
  
        glEnable(GL_LIGHTING)
        glEnable(GL_LIGHT0)
  
        glClearColor(0.0, 0.1, 0.1, 0.0)
end

# Draw twelve spheres in 3 rows with 4 columns.  
# The spheres in the first row have materials with no ambient reflection.
# The second row has materials with significant ambient reflection.
# The third row has materials with colored ambient reflection.
#
# The first column has materials with blue, diffuse reflection only.
# The second column has blue diffuse reflection, as well as specular
# reflection with a low shininess exponent.
# The third column has blue diffuse reflection, as well as specular
# reflection with a high shininess exponent (a more concentrated highlight).
# The fourth column has materials which also include an emissive component.
#
# glTranslatef() is used to move spheres to their appropriate locations.
display = proc do
        no_mat = Properties.new( 0.0, 0.0, 0.0, 1.0)
        mat_ambient = Properties.new(0.7, 0.7, 0.7, 1.0)
        mat_ambient_color = Properties.new(0.8, 0.8, 0.2, 1.0)
        mat_diffuse = Properties.new(0.1, 0.5, 0.8, 1.0)
        mat_specular = Properties.new(1.0, 1.0, 1.0, 1.0)
        no_shininess = 0.0
        low_shininess = 5.0
        high_shininess = 100.0
        mat_emission = Properties.new(0.3, 0.2, 0.2, 0.0)
  
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
  
        # draw sphere in first row, first column
        # diffuse reflection only no ambient or specular  
        glPushMatrix()
        glTranslate(-3.75, 3.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, no_mat)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, no_mat)
        glMaterial(GL_FRONT, GL_SHININESS, no_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in first row, second column
        # diffuse and specular reflection low shininess no ambient
        glPushMatrix()
        glTranslate(-1.25, 3.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, no_mat)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, mat_specular)
        glMaterial(GL_FRONT, GL_SHININESS, low_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in first row, third column
        # diffuse and specular reflection high shininess no ambient
        glPushMatrix()
        glTranslate(1.25, 3.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, no_mat)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, mat_specular)
        glMaterial(GL_FRONT, GL_SHININESS, high_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in first row, fourth column
        # diffuse reflection emission no ambient or specular reflection
        glPushMatrix()
        glTranslate(3.75, 3.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, no_mat)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, no_mat)
        glMaterial(GL_FRONT, GL_SHININESS, no_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, mat_emission)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in second row, first column
        # ambient and diffuse reflection no specular  
        glPushMatrix()
        glTranslate(-3.75, 0.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, mat_ambient)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, no_mat)
        glMaterial(GL_FRONT, GL_SHININESS, no_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in second row, second column
        # ambient, diffuse and specular reflection low shininess
        glPushMatrix()
        glTranslate(-1.25, 0.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, mat_ambient)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, mat_specular)
        glMaterial(GL_FRONT, GL_SHININESS, low_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in second row, third column
        # ambient, diffuse and specular reflection high shininess
        glPushMatrix()
        glTranslate(1.25, 0.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, mat_ambient)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, mat_specular)
        glMaterial(GL_FRONT, GL_SHININESS, high_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in second row, fourth column
        # ambient and diffuse reflection emission no specular
        glPushMatrix()
        glTranslate(3.75, 0.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, mat_ambient)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, no_mat)
        glMaterial(GL_FRONT, GL_SHININESS, no_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, mat_emission)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in third row, first column
        # colored ambient and diffuse reflection no specular  
        glPushMatrix()
        glTranslate(-3.75, -3.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, mat_ambient_color)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, no_mat)
        glMaterial(GL_FRONT, GL_SHININESS, no_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in third row, second column
        # colored ambient, diffuse and specular reflection low shininess
        glPushMatrix()
        glTranslate(-1.25, -3.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, mat_ambient_color)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, mat_specular)
        glMaterial(GL_FRONT, GL_SHININESS, low_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in third row, third column
        # colored ambient, diffuse and specular reflection high shininess
        glPushMatrix()
        glTranslate(1.25, -3.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, mat_ambient_color)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, mat_specular)
        glMaterial(GL_FRONT, GL_SHININESS, high_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, no_mat)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        # draw sphere in third row, fourth column
        # colored ambient and diffuse reflection emission no specular
        glPushMatrix()
        glTranslate(3.75, -3.0, 0.0)
        glMaterial(GL_FRONT, GL_AMBIENT, mat_ambient_color)
        glMaterial(GL_FRONT, GL_DIFFUSE, mat_diffuse)
        glMaterial(GL_FRONT, GL_SPECULAR, no_mat)
        glMaterial(GL_FRONT, GL_SHININESS, no_shininess)
        glMaterial(GL_FRONT, GL_EMISSION, mat_emission)
        glutSolidSphere(1.0, 16, 16)
        glPopMatrix()
  
        glutSwapBuffers()
end

myReshape = proc do |w, h|
        glViewport(0, 0, w, h)
        glMatrixMode(GL_PROJECTION)
        glLoadIdentity()
        if (w <= (h * 2))
                glOrtho(-6.0, 6.0, -3.0*(h.to_f*2)/w,   3.0*(h.to_f*2)/w, -10.0, 10.0)
        else
                glOrtho(-6.0*w.to_f/(h*2), 6.0*w.to_f/(h*2), -3.0, 3.0, -10.0, 10.0)
        end
        glMatrixMode(GL_MODELVIEW)
end

keyboard = Proc.new do |key, x, y|
        case (key)
                when ?\e
                exit(0);
        end
end

# Main Loop
# Open window with initial window size, title bar,
# RGBA display mode, and handle input events.
glutInit()
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH)
glutInitWindowSize(600, 600)
glutInitWindowPosition(100, 100)
glutCreateWindow([])
myinit()
glutReshapeFunc(myReshape)
glutDisplayFunc(display)
glutKeyboardFunc(keyboard)
glutMainLoop()