progs/redbook/aapoly.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  31  * Unpublished-- rights reserved under the copyright laws of the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  *  aapoly.c
  40  *  This program draws filled polygons with antialiased
  41  *  edges.  The special GL_SRC_ALPHA_SATURATE blending
  42  *  function is used.
  43  *  Pressing the 't' key turns the antialiasing on and off.
  44  */
  45 #include <GL/glut.h>
  46 #include <stdlib.h>
  47 #include <stdio.h>
  48 #include <string.h>
  49
  50 GLboolean polySmooth = GL_TRUE;
  51
  52 static void init(void)
  53 {
  54    glCullFace (GL_BACK);
  55    glEnable (GL_CULL_FACE);
  56    glBlendFunc (GL_SRC_ALPHA_SATURATE, GL_ONE);
  57    glClearColor (0.0, 0.0, 0.0, 0.0);
  58 }
  59
  60 #define NFACE 6
  61 #define NVERT 8
  62 static void drawCube(GLdouble x0, GLdouble x1, GLdouble y0, GLdouble y1,
  63         GLdouble z0, GLdouble z1)
  64 {
  65    static GLfloat v[8][3];
  66    static GLfloat c[8][4] = {
  67       {0.0, 0.0, 0.0, 1.0}, {1.0, 0.0, 0.0, 1.0},
  68       {0.0, 1.0, 0.0, 1.0}, {1.0, 1.0, 0.0, 1.0},
  69       {0.0, 0.0, 1.0, 1.0}, {1.0, 0.0, 1.0, 1.0},
  70       {0.0, 1.0, 1.0, 1.0}, {1.0, 1.0, 1.0, 1.0}
  71    };
  72
  73 /*  indices of front, top, left, bottom, right, back faces  */
  74    static GLubyte indices[NFACE][4] = {
  75       {4, 5, 6, 7}, {2, 3, 7, 6}, {0, 4, 7, 3},
  76       {0, 1, 5, 4}, {1, 5, 6, 2}, {0, 3, 2, 1}
  77    };
  78
  79    v[0][0] = v[3][0] = v[4][0] = v[7][0] = x0;
  80    v[1][0] = v[2][0] = v[5][0] = v[6][0] = x1;
  81    v[0][1] = v[1][1] = v[4][1] = v[5][1] = y0;
  82    v[2][1] = v[3][1] = v[6][1] = v[7][1] = y1;
  83    v[0][2] = v[1][2] = v[2][2] = v[3][2] = z0;
  84    v[4][2] = v[5][2] = v[6][2] = v[7][2] = z1;
  85
  86 #ifdef GL_VERSION_1_1
  87    glEnableClientState (GL_VERTEX_ARRAY);
  88    glEnableClientState (GL_COLOR_ARRAY);
  89    glVertexPointer (3, GL_FLOAT, 0, v);
  90    glColorPointer (4, GL_FLOAT, 0, c);
  91    glDrawElements (GL_QUADS, NFACE*4, GL_UNSIGNED_BYTE, indices);
  92    glDisableClientState (GL_VERTEX_ARRAY);
  93    glDisableClientState (GL_COLOR_ARRAY);
  94 #else
  95    printf ("If this is GL Version 1.0, ");
  96    printf ("vertex arrays are not supported.\n");
  97    exit(1);
  98 #endif
  99 }
 100
 101 /*  Note:  polygons must be drawn from front to back
 102  *  for proper blending.
 103  */
 104 static void display(void)
 105 {
 106    if (polySmooth) {
 107       glClear (GL_COLOR_BUFFER_BIT);
 108       glEnable (GL_BLEND);
 109       glEnable (GL_POLYGON_SMOOTH);
 110       glDisable (GL_DEPTH_TEST);
 111    }
 112    else {
 113       glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 114       glDisable (GL_BLEND);
 115       glDisable (GL_POLYGON_SMOOTH);
 116       glEnable (GL_DEPTH_TEST);
 117    }
 118
 119    glPushMatrix ();
 120       glTranslatef (0.0, 0.0, -8.0);
 121       glRotatef (30.0, 1.0, 0.0, 0.0);
 122       glRotatef (60.0, 0.0, 1.0, 0.0);
 123       drawCube(-0.5, 0.5, -0.5, 0.5, -0.5, 0.5);
 124    glPopMatrix ();
 125
 126    glFlush ();
 127 }
 128
 129 static void reshape(int w, int h)
 130 {
 131    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
 132    glMatrixMode(GL_PROJECTION);
 133    glLoadIdentity();
 134    gluPerspective(30.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
 135    glMatrixMode(GL_MODELVIEW);
 136    glLoadIdentity();
 137 }
 138
 139 /* ARGSUSED1 */
 140 static void keyboard(unsigned char key, int x, int y)
 141 {
 142    switch (key) {
 143       case 't':
 144       case 'T':
 145          polySmooth = !polySmooth;
 146          glutPostRedisplay();
 147          break;
 148       case 27:
 149          exit(0);  /*  Escape key  */
 150          break;
 151       default:
 152          break;
 153    }
 154 }
 155
 156 /*  Main Loop
 157  */
 158 int main(int argc, char** argv)
 159 {
 160    glutInit(&argc, argv);
 161    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB
 162                         | GLUT_ALPHA | GLUT_DEPTH);
 163    glutInitWindowSize(200, 200);
 164    glutCreateWindow(argv[0]);
 165    init ();
 166    glutReshapeFunc (reshape);
 167    glutKeyboardFunc (keyboard);
 168    glutDisplayFunc (display);
 169    glutMainLoop();
 170    return 0;
 171 }
 172