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#
# 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# Unpublished-- rights reserved under the copyright laws of the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.
#
# bezcurve.c
# This program uses evaluators to draw a Bezier curve.
require "opengl"
include Gl,Glu,Glut
$ctrlpoints = [
[-4.0,-4.0, 0.0],
[-2.0, 4.0, 0.0],
[ 2.0,-4.0, 0.0],
[ 4.0, 4.0, 0.0]
]
def init
glClearColor(0.0, 0.0, 0.0, 0.0)
glShadeModel(GL_FLAT)
glMap1d(GL_MAP1_VERTEX_3, 0.0, 1.0, 3, 4, $ctrlpoints.flatten)
glEnable(GL_MAP1_VERTEX_3)
end
display = proc do
glClear(GL_COLOR_BUFFER_BIT)
glColor(1.0, 1.0, 1.0)
glBegin(GL_LINE_STRIP)
for i in 0..30
glEvalCoord1d(i.to_f/30.0)
end
glEnd()
# The following code displays the control points as dots.
glPointSize(5.0)
glColor(1.0, 1.0, 0.0)
glBegin(GL_POINTS)
for i in 0...4
glVertex($ctrlpoints[i])
end
glEnd()
glutSwapBuffers()
end
reshape = proc do |w, h|
glViewport(0, 0, w, h)
glMatrixMode(GL_PROJECTION)
glLoadIdentity()
if (w <= h)
glOrtho(-5.0, 5.0, -5.0*h/w, 5.0*h/w, -5.0, 5.0)
else
glOrtho(-5.0*w/h, 5.0*w/h, -5.0, 5.0, -5.0, 5.0)
end
glMatrixMode(GL_MODELVIEW)
glLoadIdentity()
end
keyboard = proc 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()
init()
glutDisplayFunc(display)
glutReshapeFunc(reshape)
glutKeyboardFunc(keyboard)
glutMainLoop()
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