progs/redbook/multisamp.c

   1 /*
   2  * Copyright (c) 1993-2003, Silicon Graphics, Inc.
   3  * All Rights Reserved
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose and without fee is hereby granted, provided that the above
   7  * copyright notice appear in all copies and that both the copyright
   8  * notice and this permission notice appear in supporting documentation,
   9  * and that the name of Silicon Graphics, Inc. not be used in
  10  * advertising or publicity pertaining to distribution of the software
  11  * without specific, written prior permission.
  12  *
  13  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" AND
  14  * WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  16  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  17  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  18  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  19  * OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, LOSS OF
  20  * PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF THIRD
  21  * PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN ADVISED OF
  22  * THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON ANY THEORY OF
  23  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE POSSESSION, USE
  24  * OR PERFORMANCE OF THIS SOFTWARE.
  25  *
  26  * US Government Users Restricted Rights
  27  * Use, duplication, or disclosure by the Government is subject to
  28  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  29  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  30  * clause at DFARS 252.227-7013 and/or in similar or successor clauses
  31  * in the FAR or the DOD or NASA FAR Supplement.  Unpublished - rights
  32  * reserved under the copyright laws of the United States.
  33  *
  34  * Contractor/manufacturer is:
  35  *      Silicon Graphics, Inc.
  36  *      1500 Crittenden Lane
  37  *      Mountain View, CA  94043
  38  *      United State of America
  39  *
  40  * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
  41  */
  42
  43 /*
  44  *  multisamp.c
  45  *  This program draws shows how to use multisampling to
  46  *  draw anti-aliased geometric primitives.  The same
  47  *  display list, a pinwheel of triangles and lines of
  48  *  varying widths, is rendered twice.  Multisampling is
  49  *  enabled when the left side is drawn.  Multisampling is
  50  *  disabled when the right side is drawn.
  51  *
  52  *  Pressing the 'b' key toggles drawing of the checkerboard
  53  *  background.  Antialiasing is sometimes easier to see
  54  *  when objects are rendered over a contrasting background.
  55  */
  56 #include <GL/glut.h>
  57 #include <stdlib.h>
  58 #include <stdio.h>
  59
  60 static int bgtoggle = 1;
  61
  62 /*
  63  *  Print out state values related to multisampling.
  64  *  Create display list with "pinwheel" of lines and
  65  *  triangles.
  66  */
  67 static void init(void)
  68 {
  69    static GLint buf[1], sbuf[1];
  70    int i, j;
  71
  72    glClearColor(0.0, 0.0, 0.0, 0.0);
  73    glGetIntegerv (GL_SAMPLE_BUFFERS_ARB, buf);
  74    printf ("number of sample buffers is %d\n", buf[0]);
  75    glGetIntegerv (GL_SAMPLES_ARB, sbuf);
  76    printf ("number of samples is %d\n", sbuf[0]);
  77
  78    glNewList (1, GL_COMPILE);
  79    for (i = 0; i < 19; i++) {
  80       glPushMatrix();
  81       glRotatef(360.0*(float)i/19.0, 0.0, 0.0, 1.0);
  82       glColor3f (1.0, 1.0, 1.0);
  83       glLineWidth((i%3)+1.0);
  84       glBegin (GL_LINES);
  85          glVertex2f (0.25, 0.05);
  86          glVertex2f (0.9, 0.2);
  87       glEnd ();
  88       glColor3f (0.0, 1.0, 1.0);
  89       glBegin (GL_TRIANGLES);
  90          glVertex2f (0.25, 0.0);
  91          glVertex2f (0.9, 0.0);
  92          glVertex2f (0.875, 0.10);
  93       glEnd ();
  94       glPopMatrix();
  95    }
  96    glEndList ();
  97
  98    glNewList (2, GL_COMPILE);
  99    glColor3f (1.0, 0.5, 0.0);
 100    glBegin (GL_QUADS);
 101    for (i = 0; i < 16; i++) {
 102       for (j = 0; j < 16; j++) {
 103          if (((i + j) % 2) == 0) {
 104             glVertex2f (-2.0 + (i * 0.25), -2.0 + (j * 0.25));
 105             glVertex2f (-2.0 + (i * 0.25), -1.75 + (j * 0.25));
 106             glVertex2f (-1.75 + (i * 0.25), -1.75 + (j * 0.25));
 107             glVertex2f (-1.75 + (i * 0.25), -2.0 + (j * 0.25));
 108          }
 109       }
 110    }
 111    glEnd ();
 112    glEndList ();
 113 }
 114
 115 /*  Draw two sets of primitives, so that you can
 116  *  compare the user of multisampling against its absence.
 117  *
 118  *  This code enables antialiasing and draws one display list
 119  *  and disables and draws the other display list
 120  */
 121 static void display(void)
 122 {
 123    glClear(GL_COLOR_BUFFER_BIT);
 124
 125    if (bgtoggle)
 126       glCallList (2);
 127
 128    glEnable (GL_MULTISAMPLE_ARB);
 129    glPushMatrix();
 130    glTranslatef (-1.0, 0.0, 0.0);
 131    glCallList (1);
 132    glPopMatrix();
 133
 134    glDisable (GL_MULTISAMPLE_ARB);
 135    glPushMatrix();
 136    glTranslatef (1.0, 0.0, 0.0);
 137    glCallList (1);
 138    glPopMatrix();
 139    glutSwapBuffers();
 140 }
 141
 142 static void reshape(int w, int h)
 143 {
 144    glViewport(0, 0, w, h);
 145    glMatrixMode(GL_PROJECTION);
 146    glLoadIdentity();
 147    if (w <= (2 * h))
 148       gluOrtho2D (-2.0, 2.0,
 149          -2.0*(GLfloat)h/(GLfloat)w, 2.0*(GLfloat)h/(GLfloat)w);
 150    else
 151       gluOrtho2D (-2.0*(GLfloat)w/(GLfloat)h,
 152          2.0*(GLfloat)w/(GLfloat)h, -2.0, 2.0);
 153    glMatrixMode(GL_MODELVIEW);
 154    glLoadIdentity();
 155 }
 156
 157 static void keyboard(unsigned char key, int x, int y)
 158 {
 159    switch (key) {
 160       case 'b':
 161       case 'B':
 162          bgtoggle = !bgtoggle;
 163          glutPostRedisplay();
 164          break;
 165       case 27:  /*  Escape Key  */
 166          exit(0);
 167       default:
 168          break;
 169     }
 170 }
 171
 172 /*  Main Loop
 173  *  Open window with initial window size, title bar,
 174  *  RGBA display mode, and handle input events.
 175  */
 176 int main(int argc, char** argv)
 177 {
 178    glutInit(&argc, argv);
 179    glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_MULTISAMPLE);
 180    glutInitWindowSize (600, 300);
 181    glutCreateWindow (argv[0]);
 182    init();
 183    glutReshapeFunc (reshape);
 184    glutKeyboardFunc (keyboard);
 185    glutDisplayFunc (display);
 186    glutMainLoop();
 187    return 0;
 188 }