progs/redbook/anti.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  34  * Unpublished-- rights reserved under the copyright laws of the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  *  anti.c
  42  *  This program draws antialiased lines in RGBA mode.
  43  */
  44 #include <stdlib.h>
  45 #include <stdio.h>
  46 #include <GL/glut.h>
  47
  48 /*  Initialize antialiasing for RGBA mode, including alpha
  49  *  blending, hint, and line width.  Print out implementation
  50  *  specific info on line width granularity and width.
  51  */
  52 static void myinit(void)
  53 {
  54     GLfloat values[2];
  55     glGetFloatv (GL_LINE_WIDTH_GRANULARITY, values);
  56     printf ("GL_LINE_WIDTH_GRANULARITY value is %3.1f\n", values[0]);
  57
  58     glGetFloatv (GL_LINE_WIDTH_RANGE, values);
  59     printf ("GL_LINE_WIDTH_RANGE values are %3.1f %3.1f\n",
  60         values[0], values[1]);
  61
  62     glEnable (GL_LINE_SMOOTH);
  63     glEnable (GL_BLEND);
  64     glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  65     glHint (GL_LINE_SMOOTH_HINT, GL_DONT_CARE);
  66     glLineWidth (1.5);
  67
  68     glShadeModel(GL_FLAT);
  69     glClearColor(0.0, 0.0, 0.0, 0.0);
  70     glDepthFunc(GL_LESS);
  71     glEnable(GL_DEPTH_TEST);
  72 }
  73
  74 /*  display() draws an icosahedron with a large alpha value, 1.0.
  75  */
  76 static void display(void)
  77 {
  78     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  79     glColor4f (1.0, 1.0, 1.0, 1.0);
  80     glutWireIcosahedron();
  81     glFlush();
  82 }
  83
  84 static void myReshape(int w, int h)
  85 {
  86     glViewport(0, 0, w, h);
  87     glMatrixMode(GL_PROJECTION);
  88     glLoadIdentity();
  89     gluPerspective (45.0, (GLfloat) w/(GLfloat) h, 3.0, 5.0);
  90
  91     glMatrixMode(GL_MODELVIEW);
  92     glLoadIdentity ();
  93     glTranslatef (0.0, 0.0, -4.0);  /*  move object into view   */
  94 }
  95
  96 static void
  97 key(unsigned char k, int x, int y)
  98 {
  99   switch (k) {
 100   case 27:  /* Escape */
 101     exit(0);
 102     break;
 103   default:
 104     return;
 105   }
 106   glutPostRedisplay();
 107 }
 108
 109 /*  Main Loop
 110  *  Open window with initial window size, title bar,
 111  *  RGBA display mode, and handle input events.
 112  */
 113 int main(int argc, char** argv)
 114 {
 115     glutInit(&argc, argv);
 116     glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 117     glutCreateWindow (argv[0]);
 118     myinit();
 119     glutReshapeFunc (myReshape);
 120     glutDisplayFunc(display);
 121     glutKeyboardFunc(key);
 122     glutMainLoop();
 123     return 0;             /* ANSI C requires main to return int. */
 124 }