141 lines
4.7 KiB
C
141 lines
4.7 KiB
C
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/* Copyright (c) Mark J. Kilgard, 1994. */
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/*
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* (c) Copyright 1993, 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(TM) is a trademark of Silicon Graphics, Inc.
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*/
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/* checker.c
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* This program texture maps a checkerboard image onto
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* two rectangles. This program clamps the texture, if
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* the texture coordinates fall outside 0.0 and 1.0.
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*/
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#include <stdlib.h>
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#include <GL/glut.h>
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/* Create checkerboard texture */
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#define checkImageWidth 64
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#define checkImageHeight 64
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GLubyte checkImage[checkImageWidth][checkImageHeight][3];
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void makeCheckImage(void)
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{
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int i, j, c;
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for (i = 0; i < checkImageWidth; i++) {
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for (j = 0; j < checkImageHeight; j++) {
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c = ((((i&0x8)==0)^((j&0x8)==0)))*255;
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checkImage[i][j][0] = (GLubyte) c;
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checkImage[i][j][1] = (GLubyte) c;
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checkImage[i][j][2] = (GLubyte) c;
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}
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}
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}
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void myinit(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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glDepthFunc(GL_LESS);
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makeCheckImage();
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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glTexImage2D(GL_TEXTURE_2D, 0, 3, checkImageWidth,
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checkImageHeight, 0, GL_RGB, GL_UNSIGNED_BYTE,
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&checkImage[0][0][0]);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
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glEnable(GL_TEXTURE_2D);
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glShadeModel(GL_FLAT);
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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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glBegin(GL_QUADS);
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glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
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glTexCoord2f(0.0, 1.0); glVertex3f(-2.0, 1.0, 0.0);
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glTexCoord2f(1.0, 1.0); glVertex3f(0.0, 1.0, 0.0);
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glTexCoord2f(1.0, 0.0); glVertex3f(0.0, -1.0, 0.0);
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glTexCoord2f(0.0, 0.0); glVertex3f(1.0, -1.0, 0.0);
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glTexCoord2f(0.0, 1.0); glVertex3f(1.0, 1.0, 0.0);
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glTexCoord2f(1.0, 1.0); glVertex3f(2.41421, 1.0, -1.41421);
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glTexCoord2f(1.0, 0.0); glVertex3f(2.41421, -1.0, -1.41421);
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glEnd();
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glutSwapBuffers();
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}
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void myReshape(int w, int h)
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{
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glViewport(0, 0, w, h);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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gluPerspective(60.0, 1.0*(GLfloat)w/(GLfloat)h, 1.0, 30.0);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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glTranslatef(0.0, 0.0, -3.6);
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}
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static void
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key(unsigned char k, int x, int y)
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{
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switch (k) {
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case 27: /* Escape */
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exit(0);
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break;
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default:
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return;
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}
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glutPostRedisplay();
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}
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int
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main(int argc, char** argv)
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{
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glutInit(&argc, argv);
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glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
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glutCreateWindow("checker");
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myinit();
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glutReshapeFunc (myReshape);
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glutDisplayFunc(display);
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glutKeyboardFunc(key);
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glutMainLoop();
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return 0; /* ANSI C requires main to return int. */
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}
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