progs/redbook/texsub.c

   1 /*
   2  * Copyright (c) 1993-1997, Silicon Graphics, Inc.
   3  * ALL RIGHTS RESERVED
   4  * Permission to use, copy, modify, and distribute this software for
   5  * any purpose and without fee is hereby granted, provided that the above
   6  * copyright notice appear in all copies and that both the copyright notice
   7  * and this permission notice appear in supporting documentation, and that
   8  * the name of Silicon Graphics, Inc. not be used in advertising
   9  * or publicity pertaining to distribution of the software without specific,
  10  * written prior permission.
  11  *
  12  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
  13  * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  14  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  15  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  16  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  17  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
  18  * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
  19  * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
  20  * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
  21  * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
  22  * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
  23  * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
  24  *
  25  * US Government Users Restricted Rights
  26  * Use, duplication, or disclosure by the Government is subject to
  27  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  28  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  29  * clause at DFARS 252.227-7013 and/or in similar or successor
  30  * clauses in the FAR or the DOD or NASA FAR Supplement.
  31  * Unpublished-- rights reserved under the copyright laws of the
  32  * United States.  Contractor/manufacturer is Silicon Graphics,
  33  * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
  34  *
  35  * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
  36  */
  37
  38 /*  texsub.c
  39  *  This program texture maps a checkerboard image onto
  40  *  two rectangles.  This program clamps the texture, if
  41  *  the texture coordinates fall outside 0.0 and 1.0.
  42  *  If the s key is pressed, a texture subimage is used to
  43  *  alter the original texture.  If the r key is pressed,
  44  *  the original texture is restored.
  45  */
  46 #include <GL/glut.h>
  47 #include <stdlib.h>
  48 #include <stdio.h>
  49
  50 #ifdef GL_VERSION_1_1
  51 /*  Create checkerboard textures  */
  52 #define checkImageWidth 64
  53 #define checkImageHeight 64
  54 #define subImageWidth 16
  55 #define subImageHeight 16
  56 static GLubyte checkImage[checkImageHeight][checkImageWidth][4];
  57 static GLubyte subImage[subImageHeight][subImageWidth][4];
  58
  59 static GLuint texName;
  60
  61 static void makeCheckImages(void)
  62 {
  63    int i, j, c;
  64
  65    for (i = 0; i < checkImageHeight; i++) {
  66       for (j = 0; j < checkImageWidth; j++) {
  67          c = ((((i&0x8)==0)^((j&0x8)==0)))*255;
  68          checkImage[i][j][0] = (GLubyte) c;
  69          checkImage[i][j][1] = (GLubyte) c;
  70          checkImage[i][j][2] = (GLubyte) c;
  71          checkImage[i][j][3] = (GLubyte) 255;
  72       }
  73    }
  74    for (i = 0; i < subImageHeight; i++) {
  75       for (j = 0; j < subImageWidth; j++) {
  76          c = ((((i&0x4)==0)^((j&0x4)==0)))*255;
  77          subImage[i][j][0] = (GLubyte) c;
  78          subImage[i][j][1] = (GLubyte) 0;
  79          subImage[i][j][2] = (GLubyte) 0;
  80          subImage[i][j][3] = (GLubyte) 255;
  81       }
  82    }
  83 }
  84
  85 static void init(void)
  86 {
  87    glClearColor (0.0, 0.0, 0.0, 0.0);
  88    glShadeModel(GL_FLAT);
  89    glEnable(GL_DEPTH_TEST);
  90
  91    makeCheckImages();
  92    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  93
  94    glGenTextures(1, &texName);
  95    glBindTexture(GL_TEXTURE_2D, texName);
  96
  97    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  98    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  99    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 100    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 101    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth, checkImageHeight,
 102                 0, GL_RGBA, GL_UNSIGNED_BYTE, checkImage);
 103 }
 104
 105 static void display(void)
 106 {
 107    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 108    glEnable(GL_TEXTURE_2D);
 109    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
 110    glBindTexture(GL_TEXTURE_2D, texName);
 111    glBegin(GL_QUADS);
 112    glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
 113    glTexCoord2f(0.0, 1.0); glVertex3f(-2.0, 1.0, 0.0);
 114    glTexCoord2f(1.0, 1.0); glVertex3f(0.0, 1.0, 0.0);
 115    glTexCoord2f(1.0, 0.0); glVertex3f(0.0, -1.0, 0.0);
 116
 117    glTexCoord2f(0.0, 0.0); glVertex3f(1.0, -1.0, 0.0);
 118    glTexCoord2f(0.0, 1.0); glVertex3f(1.0, 1.0, 0.0);
 119    glTexCoord2f(1.0, 1.0); glVertex3f(2.41421, 1.0, -1.41421);
 120    glTexCoord2f(1.0, 0.0); glVertex3f(2.41421, -1.0, -1.41421);
 121    glEnd();
 122    glFlush();
 123    glDisable(GL_TEXTURE_2D);
 124 }
 125
 126 static void reshape(int w, int h)
 127 {
 128    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
 129    glMatrixMode(GL_PROJECTION);
 130    glLoadIdentity();
 131    gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 30.0);
 132    glMatrixMode(GL_MODELVIEW);
 133    glLoadIdentity();
 134    glTranslatef(0.0, 0.0, -3.6);
 135 }
 136
 137 /* ARGSUSED1 */
 138 static void keyboard (unsigned char key, int x, int y)
 139 {
 140    switch (key) {
 141       case 's':
 142       case 'S':
 143          glBindTexture(GL_TEXTURE_2D, texName);
 144          glTexSubImage2D(GL_TEXTURE_2D, 0, 12, 44, subImageWidth,
 145                          subImageHeight, GL_RGBA,
 146                          GL_UNSIGNED_BYTE, subImage);
 147          glutPostRedisplay();
 148          break;
 149       case 'r':
 150       case 'R':
 151          glBindTexture(GL_TEXTURE_2D, texName);
 152          glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth,
 153                       checkImageHeight, 0, GL_RGBA,
 154                       GL_UNSIGNED_BYTE, checkImage);
 155          glutPostRedisplay();
 156          break;
 157       case 27:
 158          exit(0);
 159          break;
 160       default:
 161          break;
 162    }
 163 }
 164
 165 int main(int argc, char** argv)
 166 {
 167    glutInit(&argc, argv);
 168    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 169    glutInitWindowSize(250, 250);
 170    glutInitWindowPosition(100, 100);
 171    glutCreateWindow(argv[0]);
 172    init();
 173    glutDisplayFunc(display);
 174    glutReshapeFunc(reshape);
 175    glutKeyboardFunc(keyboard);
 176    glutMainLoop();
 177    return 0;
 178 }
 179 #else
 180 int main(int argc, char** argv)
 181 {
 182     fprintf (stderr, "This program demonstrates a feature which is not in OpenGL Version 1.0.\n");
 183     fprintf (stderr, "If your implementation of OpenGL Version 1.0 has the right extensions,\n");
 184     fprintf (stderr, "you may be able to modify this program to make it run.\n");
 185     return 0;
 186 }
 187 #endif