src/redbook/mipmap.c

   1
   2 /* Copyright (c) Mark J. Kilgard, 1994. */
   3
   4 /*
   5  * (c) Copyright 1993, Silicon Graphics, Inc.
   6  * ALL RIGHTS RESERVED
   7  * Permission to use, copy, modify, and distribute this software for
   8  * any purpose and without fee is hereby granted, provided that the above
   9  * copyright notice appear in all copies and that both the copyright notice
  10  * and this permission notice appear in supporting documentation, and that
  11  * the name of Silicon Graphics, Inc. not be used in advertising
  12  * or publicity pertaining to distribution of the software without specific,
  13  * written prior permission.
  14  *
  15  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
  16  * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  18  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  19  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  20  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
  21  * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
  22  * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
  23  * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
  24  * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
  25  * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
  26  * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
  27  *
  28  * US Government Users Restricted Rights
  29  * Use, duplication, or disclosure by the Government is subject to
  30  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  31  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  32  * clause at DFARS 252.227-7013 and/or in similar or successor
  33  * clauses in the FAR or the DOD or NASA FAR Supplement.
  34  * Unpublished-- rights reserved under the copyright laws of the
  35  * United States.  Contractor/manufacturer is Silicon Graphics,
  36  * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
  37  *
  38  * OpenGL(TM) is a trademark of Silicon Graphics, Inc.
  39  */
  40 /*  mipmap.c
  41  *  This program demonstrates using mipmaps for texture maps.
  42  *  To overtly show the effect of mipmaps, each mipmap reduction
  43  *  level has a solidly colored, contrasting texture image.
  44  *  Thus, the quadrilateral which is drawn is drawn with several
  45  *  different colors.
  46  */
  47 #include <stdlib.h>
  48 #include "glut_wrap.h"
  49
  50 GLubyte mipmapImage32[32][32][3];
  51 GLubyte mipmapImage16[16][16][3];
  52 GLubyte mipmapImage8[8][8][3];
  53 GLubyte mipmapImage4[4][4][3];
  54 GLubyte mipmapImage2[2][2][3];
  55 GLubyte mipmapImage1[1][1][3];
  56
  57 static void makeImages(void)
  58 {
  59     int i, j;
  60
  61     for (i = 0; i < 32; i++) {
  62         for (j = 0; j < 32; j++) {
  63             mipmapImage32[i][j][0] = 255;
  64             mipmapImage32[i][j][1] = 255;
  65             mipmapImage32[i][j][2] = 0;
  66         }
  67     }
  68     for (i = 0; i < 16; i++) {
  69         for (j = 0; j < 16; j++) {
  70             mipmapImage16[i][j][0] = 255;
  71             mipmapImage16[i][j][1] = 0;
  72             mipmapImage16[i][j][2] = 255;
  73         }
  74     }
  75     for (i = 0; i < 8; i++) {
  76         for (j = 0; j < 8; j++) {
  77             mipmapImage8[i][j][0] = 255;
  78             mipmapImage8[i][j][1] = 0;
  79             mipmapImage8[i][j][2] = 0;
  80         }
  81     }
  82     for (i = 0; i < 4; i++) {
  83         for (j = 0; j < 4; j++) {
  84             mipmapImage4[i][j][0] = 0;
  85             mipmapImage4[i][j][1] = 255;
  86             mipmapImage4[i][j][2] = 0;
  87         }
  88     }
  89     for (i = 0; i < 2; i++) {
  90         for (j = 0; j < 2; j++) {
  91             mipmapImage2[i][j][0] = 0;
  92             mipmapImage2[i][j][1] = 0;
  93             mipmapImage2[i][j][2] = 255;
  94         }
  95     }
  96     mipmapImage1[0][0][0] = 255;
  97     mipmapImage1[0][0][1] = 255;
  98     mipmapImage1[0][0][2] = 255;
  99 }
 100
 101 static void myinit(void)
 102 {
 103     glEnable(GL_DEPTH_TEST);
 104     glDepthFunc(GL_LESS);
 105     glShadeModel(GL_FLAT);
 106
 107     glTranslatef(0.0, 0.0, -3.6);
 108     makeImages();
 109     glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 110     glTexImage2D(GL_TEXTURE_2D, 0, 3, 32, 32, 0,
 111                  GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage32[0][0][0]);
 112     glTexImage2D(GL_TEXTURE_2D, 1, 3, 16, 16, 0,
 113                  GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage16[0][0][0]);
 114     glTexImage2D(GL_TEXTURE_2D, 2, 3, 8, 8, 0,
 115                  GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage8[0][0][0]);
 116     glTexImage2D(GL_TEXTURE_2D, 3, 3, 4, 4, 0,
 117                  GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage4[0][0][0]);
 118     glTexImage2D(GL_TEXTURE_2D, 4, 3, 2, 2, 0,
 119                  GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage2[0][0][0]);
 120     glTexImage2D(GL_TEXTURE_2D, 5, 3, 1, 1, 0,
 121                  GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage1[0][0][0]);
 122     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 123     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 124     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 125     glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
 126         GL_NEAREST_MIPMAP_NEAREST);
 127     glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
 128     glEnable(GL_TEXTURE_2D);
 129 }
 130
 131 static void display(void)
 132 {
 133     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 134     glBegin(GL_QUADS);
 135     glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
 136     glTexCoord2f(0.0, 8.0); glVertex3f(-2.0, 1.0, 0.0);
 137     glTexCoord2f(8.0, 8.0); glVertex3f(2000.0, 1.0, -6000.0);
 138     glTexCoord2f(8.0, 0.0); glVertex3f(2000.0, -1.0, -6000.0);
 139     glEnd();
 140     glFlush();
 141 }
 142
 143 static void myReshape(int w, int h)
 144 {
 145     glViewport(0, 0, w, h);
 146     glMatrixMode(GL_PROJECTION);
 147     glLoadIdentity();
 148     gluPerspective(60.0, 1.0*(GLfloat)w/(GLfloat)h, 1.0, 30000.0);
 149     glMatrixMode(GL_MODELVIEW);
 150     glLoadIdentity();
 151 }
 152
 153 static void
 154 key(unsigned char k, int x, int y)
 155 {
 156   switch (k) {
 157   case 27:  /* Escape */
 158     exit(0);
 159     break;
 160   default:
 161     return;
 162   }
 163   glutPostRedisplay();
 164 }
 165
 166 int main(int argc, char** argv)
 167 {
 168     glutInit(&argc, argv);
 169     glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 170     glutInitWindowSize (500, 500);
 171     glutCreateWindow (argv[0]);
 172     myinit();
 173     glutReshapeFunc (myReshape);
 174     glutDisplayFunc(display);
 175     glutKeyboardFunc(key);
 176     glutMainLoop();
 177     return 0;             /* ANSI C requires main to return int. */
 178 }