#
# Copyright (c) 1993-1997, Silicon Graphics, Inc.
# ALL RIGHTS RESERVED
# Permission to use, copy, modify, and distribute this software for
# any purpose and without fee is hereby granted, provided that the above
# copyright notice appear in all copies and that both the copyright notice
# and this permission notice appear in supporting documentation, and that
# the name of Silicon Graphics, Inc. not be used in advertising
# or publicity pertaining to distribution of the software without specific,
# written prior permission.
#
# THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
# AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
# INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
# FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
# GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
# SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
# KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
# LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
# THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
# ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
# 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# Unpublished-- rights reserved under the copyright laws of the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(R) is a registered trademark of Silicon Graphics, Inc.
#
# smooth.c
# This program demonstrates smooth shading.
# A smooth shaded polygon is drawn in a 2-D projection.

require 'opengl'
require 'glu'
require 'glut'
include Gl,Glu,Glut

def init
  glClearColor(0,0,0,0)
  glShadeModel(GL_SMOOTH)
end

def triangle
  glBegin(GL_TRIANGLES)
  glColor3f(1.0, 0.0, 0.0)
  glVertex2f(5, 5)
  glColor3f(0.0, 1.0, 0.0)
  glVertex2f(25, 5)
  glColor3f(0.0, 0.0, 1.0)
  glVertex2f(5, 25)
  glEnd()
end


display = Proc.new do
  glClear(GL_COLOR_BUFFER_BIT)
  triangle
  glutSwapBuffers()
end

reshape = Proc.new do |w, h|
  glViewport(0, 0, w, h)
  glMatrixMode(GL_PROJECTION)
  glLoadIdentity
  if w<=h
    gluOrtho2D(0,30,0, 30 * h/w)
  else
    gluOrtho2D(0,30 * w/h, 0,30)
  end
  glMatrixMode(GL_MODELVIEW)
end

keyboard = lambda do |key, x, y|
  case(key)
  when ?\e
    exit(0)
  end
end

glutInit()
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB)
glutInitWindowSize(500, 500)
glutInitWindowPosition(100, 100)
glutCreateWindow($0)
init()
glutDisplayFunc(display)
glutReshapeFunc(reshape)
glutKeyboardFunc(keyboard)
glutMainLoop()
