progs/redbook/aargb.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  31  * Unpublished-- rights reserved under the copyright laws of the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  *  aargb.c
  40  *  This program draws shows how to draw anti-aliased lines. It draws
  41  *  two diagonal lines to form an X; when 'r' is typed in the window,
  42  *  the lines are rotated in opposite directions.
  43  */
  44 #include <GL/glut.h>
  45 #include <stdlib.h>
  46 #include <stdio.h>
  47
  48 static float rotAngle = 0.;
  49
  50 /*  Initialize antialiasing for RGBA mode, including alpha
  51  *  blending, hint, and line width.  Print out implementation
  52  *  specific info on line width granularity and width.
  53  */
  54 void init(void)
  55 {
  56    GLfloat values[2];
  57    glGetFloatv (GL_LINE_WIDTH_GRANULARITY, values);
  58    printf ("GL_LINE_WIDTH_GRANULARITY value is %3.1f\n", values[0]);
  59
  60    glGetFloatv (GL_LINE_WIDTH_RANGE, values);
  61    printf ("GL_LINE_WIDTH_RANGE values are %3.1f %3.1f\n",
  62       values[0], values[1]);
  63
  64    glEnable (GL_LINE_SMOOTH);
  65    glEnable (GL_BLEND);
  66    glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  67    glHint (GL_LINE_SMOOTH_HINT, GL_DONT_CARE);
  68    glLineWidth (1.5);
  69
  70    glClearColor(0.0, 0.0, 0.0, 0.0);
  71 }
  72
  73 /* Draw 2 diagonal lines to form an X
  74  */
  75 void display(void)
  76 {
  77    glClear(GL_COLOR_BUFFER_BIT);
  78
  79    glColor3f (0.0, 1.0, 0.0);
  80    glPushMatrix();
  81    glRotatef(-rotAngle, 0.0, 0.0, 0.1);
  82    glBegin (GL_LINES);
  83       glVertex2f (-0.5, 0.5);
  84       glVertex2f (0.5, -0.5);
  85    glEnd ();
  86    glPopMatrix();
  87
  88    glColor3f (0.0, 0.0, 1.0);
  89    glPushMatrix();
  90    glRotatef(rotAngle, 0.0, 0.0, 0.1);
  91    glBegin (GL_LINES);
  92       glVertex2f (0.5, 0.5);
  93       glVertex2f (-0.5, -0.5);
  94    glEnd ();
  95    glPopMatrix();
  96
  97    glFlush();
  98 }
  99
 100 void reshape(int w, int h)
 101 {
 102    glViewport(0, 0, w, h);
 103    glMatrixMode(GL_PROJECTION);
 104    glLoadIdentity();
 105    if (w <= h)
 106       gluOrtho2D (-1.0, 1.0,
 107          -1.0*(GLfloat)h/(GLfloat)w, 1.0*(GLfloat)h/(GLfloat)w);
 108    else
 109       gluOrtho2D (-1.0*(GLfloat)w/(GLfloat)h,
 110          1.0*(GLfloat)w/(GLfloat)h, -1.0, 1.0);
 111    glMatrixMode(GL_MODELVIEW);
 112    glLoadIdentity();
 113 }
 114
 115 /* ARGSUSED1 */
 116 void keyboard(unsigned char key, int x, int y)
 117 {
 118    switch (key) {
 119       case 'r':
 120       case 'R':
 121          rotAngle += 20.;
 122          if (rotAngle >= 360.) rotAngle = 0.;
 123          glutPostRedisplay();
 124          break;
 125       case 27:  /*  Escape Key  */
 126          exit(0);
 127          break;
 128       default:
 129          break;
 130     }
 131 }
 132
 133 /*  Main Loop
 134  *  Open window with initial window size, title bar,
 135  *  RGBA display mode, and handle input events.
 136  */
 137 int main(int argc, char** argv)
 138 {
 139    glutInit(&argc, argv);
 140    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
 141    glutInitWindowSize (200, 200);
 142    glutCreateWindow (argv[0]);
 143    init();
 144    glutReshapeFunc (reshape);
 145    glutKeyboardFunc (keyboard);
 146    glutDisplayFunc (display);
 147    glutMainLoop();
 148    return 0;
 149 }