progs/redbook/aaindex.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  31  * Unpublished-- rights reserved under the copyright laws of the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 /*
  39  *  aaindex.c
  40  *  This program draws shows how to draw anti-aliased lines in color
  41  *  index mode. It draws two diagonal lines to form an X; when 'r'
  42  *  is typed in the window, the lines are rotated in opposite
  43  *  directions.
  44  */
  45 #include <GL/glut.h>
  46 #include "stdlib.h"
  47
  48 #define RAMPSIZE 16
  49 #define RAMP1START 32
  50 #define RAMP2START 48
  51
  52 static float rotAngle = 0.;
  53
  54 /*  Initialize antialiasing for color index mode,
  55  *  including loading a green color ramp starting
  56  *  at RAMP1START, and a blue color ramp starting
  57  *  at RAMP2START. The ramps must be a multiple of 16.
  58  */
  59 static void init(void)
  60 {
  61    int i;
  62
  63    for (i = 0; i < RAMPSIZE; i++) {
  64       GLfloat shade;
  65       shade = (GLfloat) i/(GLfloat) RAMPSIZE;
  66       glutSetColor(RAMP1START+(GLint)i, 0., shade, 0.);
  67       glutSetColor(RAMP2START+(GLint)i, 0., 0., shade);
  68    }
  69
  70    glEnable (GL_LINE_SMOOTH);
  71    glHint (GL_LINE_SMOOTH_HINT, GL_DONT_CARE);
  72    glLineWidth (1.5);
  73
  74    glClearIndex ((GLfloat) RAMP1START);
  75 }
  76
  77 /*  Draw 2 diagonal lines to form an X
  78  */
  79 static void display(void)
  80 {
  81    glClear(GL_COLOR_BUFFER_BIT);
  82
  83    glIndexi(RAMP1START);
  84    glPushMatrix();
  85    glRotatef(-rotAngle, 0.0, 0.0, 0.1);
  86    glBegin (GL_LINES);
  87       glVertex2f (-0.5, 0.5);
  88       glVertex2f (0.5, -0.5);
  89    glEnd ();
  90    glPopMatrix();
  91
  92    glIndexi(RAMP2START);
  93    glPushMatrix();
  94    glRotatef(rotAngle, 0.0, 0.0, 0.1);
  95    glBegin (GL_LINES);
  96       glVertex2f (0.5, 0.5);
  97       glVertex2f (-0.5, -0.5);
  98    glEnd ();
  99    glPopMatrix();
 100
 101    glFlush();
 102 }
 103
 104 static void reshape(int w, int h)
 105 {
 106    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
 107    glMatrixMode(GL_PROJECTION);
 108    glLoadIdentity();
 109    if (w <= h)
 110       gluOrtho2D (-1.0, 1.0,
 111          -1.0*(GLfloat)h/(GLfloat)w, 1.0*(GLfloat)h/(GLfloat)w);
 112    else
 113       gluOrtho2D (-1.0*(GLfloat)w/(GLfloat)h,
 114          1.0*(GLfloat)w/(GLfloat)h, -1.0, 1.0);
 115    glMatrixMode(GL_MODELVIEW);
 116    glLoadIdentity();
 117 }
 118
 119 /* ARGSUSED1 */
 120 static void keyboard(unsigned char key, int x, int y)
 121 {
 122    switch (key) {
 123       case 'r':
 124       case 'R':
 125          rotAngle += 20.;
 126          if (rotAngle >= 360.) rotAngle = 0.;
 127          glutPostRedisplay();
 128          break;
 129       case 27:  /*  Escape Key */
 130          exit(0);
 131          break;
 132       default:
 133          break;
 134     }
 135 }
 136
 137 /*  Main Loop
 138  *  Open window with initial window size, title bar,
 139  *  color index display mode, and handle input events.
 140  */
 141 int main(int argc, char** argv)
 142 {
 143    glutInit(&argc, argv);
 144    glutInitDisplayMode (GLUT_SINGLE | GLUT_INDEX);
 145    glutInitWindowSize (200, 200);
 146    glutCreateWindow (argv[0]);
 147    init();
 148    glutReshapeFunc (reshape);
 149    glutKeyboardFunc (keyboard);
 150    glutDisplayFunc (display);
 151    glutMainLoop();
 152    return 0;
 153 }