208 lines
6.6 KiB
C
208 lines
6.6 KiB
C
/*
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* Copyright (c) 1993-1997, Silicon Graphics, Inc.
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* ALL RIGHTS RESERVED
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* Permission to use, copy, modify, and distribute this software for
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* any purpose and without fee is hereby granted, provided that the above
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* copyright notice appear in all copies and that both the copyright notice
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* and this permission notice appear in supporting documentation, and that
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* the name of Silicon Graphics, Inc. not be used in advertising
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* or publicity pertaining to distribution of the software without specific,
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* written prior permission.
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*
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* THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
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* AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
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* FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
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* GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
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* SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
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* KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
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* LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
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* THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN
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* ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
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* POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* US Government Users Restricted Rights
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* Use, duplication, or disclosure by the Government is subject to
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* restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
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* (c)(1)(ii) of the Rights in Technical Data and Computer Software
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* clause at DFARS 252.227-7013 and/or in similar or successor
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* clauses in the FAR or the DOD or NASA FAR Supplement.
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* Unpublished-- rights reserved under the copyright laws of the
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* United States. Contractor/manufacturer is Silicon Graphics,
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* Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311.
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*
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* OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
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*/
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/* texgen.c
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* This program draws a texture mapped teapot with
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* automatically generated texture coordinates. The
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* texture is rendered as stripes on the teapot.
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* Initially, the object is drawn with texture coordinates
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* based upon the object coordinates of the vertex
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* and distance from the plane x = 0. Pressing the 'e'
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* key changes the coordinate generation to eye coordinates
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* of the vertex. Pressing the 'o' key switches it back
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* to the object coordinates. Pressing the 's' key
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* changes the plane to a slanted one (x + y + z = 0).
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* Pressing the 'x' key switches it back to x = 0.
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*/
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#include <GL/glut.h>
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#include <stdlib.h>
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#include <stdio.h>
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#define stripeImageWidth 32
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GLubyte stripeImage[4*stripeImageWidth];
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#ifdef GL_VERSION_1_1
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static GLuint texName;
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#endif
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void makeStripeImage(void)
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{
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int j;
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for (j = 0; j < stripeImageWidth; j++) {
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stripeImage[4*j] = (GLubyte) ((j<=4) ? 255 : 0);
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stripeImage[4*j+1] = (GLubyte) ((j>4) ? 255 : 0);
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stripeImage[4*j+2] = (GLubyte) 0;
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stripeImage[4*j+3] = (GLubyte) 255;
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}
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}
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/* planes for texture coordinate generation */
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static GLfloat xequalzero[] = {1.0, 0.0, 0.0, 0.0};
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static GLfloat slanted[] = {1.0, 1.0, 1.0, 0.0};
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static GLfloat *currentCoeff;
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static GLenum currentPlane;
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static GLint currentGenMode;
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void init(void)
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{
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glClearColor (0.0, 0.0, 0.0, 0.0);
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glEnable(GL_DEPTH_TEST);
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glShadeModel(GL_SMOOTH);
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makeStripeImage();
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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#ifdef GL_VERSION_1_1
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glGenTextures(1, &texName);
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glBindTexture(GL_TEXTURE_1D, texName);
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#endif
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glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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#ifdef GL_VERSION_1_1
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glTexImage1D(GL_TEXTURE_1D, 0, GL_RGBA, stripeImageWidth, 0,
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GL_RGBA, GL_UNSIGNED_BYTE, stripeImage);
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#else
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glTexImage1D(GL_TEXTURE_1D, 0, 4, stripeImageWidth, 0,
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GL_RGBA, GL_UNSIGNED_BYTE, stripeImage);
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#endif
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glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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currentCoeff = xequalzero;
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currentGenMode = GL_OBJECT_LINEAR;
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currentPlane = GL_OBJECT_PLANE;
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glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, currentGenMode);
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glTexGenfv(GL_S, currentPlane, currentCoeff);
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glEnable(GL_TEXTURE_GEN_S);
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glEnable(GL_TEXTURE_1D);
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glEnable(GL_CULL_FACE);
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glEnable(GL_LIGHTING);
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glEnable(GL_LIGHT0);
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glEnable(GL_AUTO_NORMAL);
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glEnable(GL_NORMALIZE);
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glFrontFace(GL_CW);
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glCullFace(GL_BACK);
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glMaterialf (GL_FRONT, GL_SHININESS, 64.0);
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}
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void display(void)
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{
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glPushMatrix ();
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glRotatef(45.0, 0.0, 0.0, 1.0);
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#ifdef GL_VERSION_1_1
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glBindTexture(GL_TEXTURE_1D, texName);
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#endif
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glutSolidTeapot(2.0);
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glPopMatrix ();
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glFlush();
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}
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void reshape(int w, int h)
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{
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glViewport(0, 0, (GLsizei) w, (GLsizei) h);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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if (w <= h)
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glOrtho (-3.5, 3.5, -3.5*(GLfloat)h/(GLfloat)w,
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3.5*(GLfloat)h/(GLfloat)w, -3.5, 3.5);
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else
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glOrtho (-3.5*(GLfloat)w/(GLfloat)h,
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3.5*(GLfloat)w/(GLfloat)h, -3.5, 3.5, -3.5, 3.5);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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}
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/* ARGSUSED1 */
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void keyboard (unsigned char key, int x, int y)
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{
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switch (key) {
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case 'e':
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case 'E':
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currentGenMode = GL_EYE_LINEAR;
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currentPlane = GL_EYE_PLANE;
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glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, currentGenMode);
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glTexGenfv(GL_S, currentPlane, currentCoeff);
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glutPostRedisplay();
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break;
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case 'o':
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case 'O':
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currentGenMode = GL_OBJECT_LINEAR;
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currentPlane = GL_OBJECT_PLANE;
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glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, currentGenMode);
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glTexGenfv(GL_S, currentPlane, currentCoeff);
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glutPostRedisplay();
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break;
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case 's':
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case 'S':
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currentCoeff = slanted;
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glTexGenfv(GL_S, currentPlane, currentCoeff);
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glutPostRedisplay();
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break;
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case 'x':
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case 'X':
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currentCoeff = xequalzero;
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glTexGenfv(GL_S, currentPlane, currentCoeff);
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glutPostRedisplay();
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break;
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case 27:
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exit(0);
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break;
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default:
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break;
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}
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}
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int main(int argc, char** argv)
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{
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glutInit(&argc, argv);
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glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
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glutInitWindowSize(256, 256);
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glutInitWindowPosition(100, 100);
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glutCreateWindow (argv[0]);
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init ();
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glutDisplayFunc(display);
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glutReshapeFunc(reshape);
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glutKeyboardFunc(keyboard);
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glutMainLoop();
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return 0;
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}
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