progs/redbook/teaambient.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  34  * Unpublished-- rights reserved under the copyright laws of the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 /**
  41  *  teaambient.c
  42  *  This program renders three lighted, shaded teapots, with
  43  *  different ambient values.
  44  */
  45 #include <stdlib.h>
  46 #include <GL/glut.h>
  47
  48 /*  Initialize light source and lighting model.
  49  */
  50 void
  51 myinit(void)
  52 {
  53     GLfloat light_ambient[] =
  54     {0.0, 0.0, 0.0, 1.0};
  55     GLfloat light_diffuse[] =
  56     {1.0, 1.0, 1.0, 1.0};
  57     GLfloat light_specular[] =
  58     {1.0, 1.0, 1.0, 1.0};
  59 /* light_position is NOT default value */
  60     GLfloat light_position[] =
  61     {1.0, 0.0, 0.0, 0.0};
  62     GLfloat global_ambient[] =
  63     {0.75, 0.75, 0.75, 1.0};
  64
  65     glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
  66     glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
  67     glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
  68     glLightfv(GL_LIGHT0, GL_POSITION, light_position);
  69
  70     glLightModelfv(GL_LIGHT_MODEL_AMBIENT, global_ambient);
  71
  72     glFrontFace(GL_CW);
  73     glEnable(GL_LIGHTING);
  74     glEnable(GL_LIGHT0);
  75     glEnable(GL_AUTO_NORMAL);
  76     glEnable(GL_NORMALIZE);
  77     glDepthFunc(GL_LESS);
  78     glEnable(GL_DEPTH_TEST);
  79 }
  80
  81 void
  82 display(void)
  83 {
  84     GLfloat low_ambient[] =
  85     {0.1, 0.1, 0.1, 1.0};
  86     GLfloat more_ambient[] =
  87     {0.4, 0.4, 0.4, 1.0};
  88     GLfloat most_ambient[] =
  89     {1.0, 1.0, 1.0, 1.0};
  90
  91     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  92
  93     /*  material has small ambient reflection */
  94     glMaterialfv(GL_FRONT, GL_AMBIENT, low_ambient);
  95     glMaterialf(GL_FRONT, GL_SHININESS, 40.0);
  96     glPushMatrix();
  97     glTranslatef(0.0, 2.0, 0.0);
  98     glutSolidTeapot(1.0);
  99     glPopMatrix();
 100
 101     /*  material has moderate ambient reflection */
 102     glMaterialfv(GL_FRONT, GL_AMBIENT, more_ambient);
 103     glPushMatrix();
 104     glTranslatef(0.0, 0.0, 0.0);
 105     glutSolidTeapot(1.0);
 106     glPopMatrix();
 107
 108     /*  material has large ambient reflection */
 109     glMaterialfv(GL_FRONT, GL_AMBIENT, most_ambient);
 110     glPushMatrix();
 111     glTranslatef(0.0, -2.0, 0.0);
 112     glutSolidTeapot(1.0);
 113     glPopMatrix();
 114     glFlush();
 115 }
 116
 117 void
 118 myReshape(int w, int h)
 119 {
 120     glViewport(0, 0, w, h);
 121     glMatrixMode(GL_PROJECTION);
 122     glLoadIdentity();
 123     if (w <= h)
 124         glOrtho(-4.0, 4.0, -4.0 * (GLfloat) h / (GLfloat) w,
 125             4.0 * (GLfloat) h / (GLfloat) w, -10.0, 10.0);
 126     else
 127         glOrtho(-4.0 * (GLfloat) w / (GLfloat) h,
 128             4.0 * (GLfloat) w / (GLfloat) h, -4.0, 4.0, -10.0, 10.0);
 129     glMatrixMode(GL_MODELVIEW);
 130 }
 131
 132 static void
 133 key(unsigned char k, int x, int y)
 134 {
 135   switch (k) {
 136   case 27:  /* Escape */
 137     exit(0);
 138     break;
 139   default:
 140     return;
 141   }
 142   glutPostRedisplay();
 143 }
 144
 145 /*  Main Loop
 146  *  Open window with initial window size, title bar,
 147  *  RGBA display mode, and handle input events.
 148  */
 149 int
 150 main(int argc, char **argv)
 151 {
 152     glutInit(&argc, argv);
 153     glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 154     glutInitWindowSize(500, 500);
 155     glutCreateWindow(argv[0]);
 156     myinit();
 157     glutReshapeFunc(myReshape);
 158     glutDisplayFunc(display);
 159     glutKeyboardFunc(key);
 160     glutMainLoop();
 161     return 0;             /* ANSI C requires main to return int. */
 162 }