src/redbook/multitex.c

   1 /*
   2  * Copyright (c) 1993-2003, Silicon Graphics, Inc.
   3  * All Rights Reserved
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose and without fee is hereby granted, provided that the above
   7  * copyright notice appear in all copies and that both the copyright
   8  * notice and this permission notice appear in supporting documentation,
   9  * and that the name of Silicon Graphics, Inc. not be used in
  10  * advertising or publicity pertaining to distribution of the software
  11  * without specific, written prior permission.
  12  *
  13  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" AND
  14  * WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  16  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  17  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  18  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  19  * OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, LOSS OF
  20  * PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF THIRD
  21  * PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN ADVISED OF
  22  * THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON ANY THEORY OF
  23  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE POSSESSION, USE
  24  * OR PERFORMANCE OF THIS SOFTWARE.
  25  *
  26  * US Government Users Restricted Rights
  27  * Use, duplication, or disclosure by the Government is subject to
  28  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  29  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  30  * clause at DFARS 252.227-7013 and/or in similar or successor clauses
  31  * in the FAR or the DOD or NASA FAR Supplement.  Unpublished - rights
  32  * reserved under the copyright laws of the United States.
  33  *
  34  * Contractor/manufacturer is:
  35  *      Silicon Graphics, Inc.
  36  *      1500 Crittenden Lane
  37  *      Mountain View, CA  94043
  38  *      United State of America
  39  *
  40  * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
  41  */
  42
  43 /*  multitex.c
  44  */
  45 #include <GL/glew.h>
  46 #include <GL/glut.h>
  47 #include <stdlib.h>
  48 #include <stdio.h>
  49
  50
  51 static GLubyte texels0[32][32][4];
  52 static GLubyte texels1[16][16][4];
  53
  54 static void makeCheckImages(void)
  55 {
  56    int i, j;
  57
  58    for (i = 0; i < 32; i++) {
  59       for (j = 0; j < 32; j++) {
  60          texels0[i][j][0] = (GLubyte) (255 * i / 31);
  61          texels0[i][j][1] = (GLubyte) (255 * j / 31);
  62          texels0[i][j][2] = (GLubyte) (i*j)/255;
  63          texels0[i][j][3] = (GLubyte) 255;
  64       }
  65    }
  66
  67    for (i = 0; i < 16; i++) {
  68       for (j = 0; j < 16; j++) {
  69          texels1[i][j][0] = (GLubyte) 255;
  70          texels1[i][j][1] = (GLubyte) (255 * i / 15);
  71          texels1[i][j][2] = (GLubyte) (255 * j / 15);
  72          texels1[i][j][3] = (GLubyte) 255;
  73       }
  74    }
  75 }
  76
  77 static void init(void)
  78 {
  79    GLuint texNames[2];
  80
  81    glClearColor (0.0, 0.0, 0.0, 0.0);
  82    glShadeModel(GL_FLAT);
  83    glEnable(GL_DEPTH_TEST);
  84
  85    makeCheckImages();
  86    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
  87
  88    glGenTextures(2, texNames);
  89    glBindTexture(GL_TEXTURE_2D, texNames[0]);
  90    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 32, 32, 0, GL_RGBA,
  91                 GL_UNSIGNED_BYTE, texels0);
  92    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
  93                    GL_NEAREST);
  94    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
  95                    GL_NEAREST);
  96    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  97    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  98
  99    glBindTexture(GL_TEXTURE_2D, texNames[1]);
 100    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 16, 16, 0, GL_RGBA,
 101                 GL_UNSIGNED_BYTE, texels1);
 102    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 103    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 104    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 105    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 106    /*  Use the two texture objects to define two texture units
 107     *  for use in multitexturing  */
 108    glActiveTextureARB (GL_TEXTURE0_ARB);
 109    glEnable(GL_TEXTURE_2D);
 110    glBindTexture(GL_TEXTURE_2D, texNames[0]);
 111    glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
 112    glMatrixMode (GL_TEXTURE);
 113       glLoadIdentity();
 114       glTranslatef(0.5f, 0.5f, 0.0f);
 115       glRotatef(45.0f, 0.0f, 0.0f, 1.0f);
 116       glTranslatef(-0.5f, -0.5f, 0.0f);
 117    glMatrixMode (GL_MODELVIEW);
 118    glActiveTextureARB (GL_TEXTURE1_ARB);
 119    glEnable(GL_TEXTURE_2D);
 120    glBindTexture(GL_TEXTURE_2D, texNames[1]);
 121    glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 122 }
 123
 124 static void display(void)
 125 {
 126    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 127    glBegin(GL_TRIANGLES);
 128    glMultiTexCoord2fARB (GL_TEXTURE0_ARB, 0.0, 0.0);
 129    glMultiTexCoord2fARB (GL_TEXTURE1_ARB, 1.0, 0.0);
 130    glVertex2f(0.0, 0.0);
 131    glMultiTexCoord2fARB (GL_TEXTURE0_ARB, 0.5, 1.0);
 132    glMultiTexCoord2fARB (GL_TEXTURE1_ARB, 0.5, 0.0);
 133    glVertex2f(50.0, 100.0);
 134    glMultiTexCoord2fARB (GL_TEXTURE0_ARB, 1.0, 0.0);
 135    glMultiTexCoord2fARB (GL_TEXTURE1_ARB, 1.0, 1.0);
 136    glVertex2f(100.0, 0.0);
 137    glEnd();
 138    glFlush();
 139 }
 140
 141 static void reshape(int w, int h)
 142 {
 143    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
 144    glMatrixMode(GL_PROJECTION);
 145    glLoadIdentity();
 146    if (w <= h)
 147       gluOrtho2D(0.0, 100.0, 0.0, 100.0 * (GLdouble)h/(GLdouble)w);
 148    else
 149       gluOrtho2D(0.0, 100.0 * (GLdouble)w/(GLdouble)h, 0.0, 100.0);
 150    glMatrixMode(GL_MODELVIEW);
 151    glLoadIdentity();
 152 }
 153
 154 static void keyboard(unsigned char key, int x, int y)
 155 {
 156    switch (key) {
 157       case 27:
 158          exit(0);
 159          break;
 160    }
 161 }
 162
 163 int main(int argc, char** argv)
 164 {
 165    glutInit(&argc, argv);
 166    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 167    glutInitWindowSize(250, 250);
 168    glutInitWindowPosition(100, 100);
 169    glutCreateWindow(argv[0]);
 170    glewInit();
 171    init();
 172    glutReshapeFunc(reshape);
 173    glutDisplayFunc(display);
 174    glutKeyboardFunc (keyboard);
 175    glutMainLoop();
 176    return 0;
 177 }