progs/redbook/stroke.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  34  * Unpublished-- rights reserved under the copyright laws of the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  *  stroke.c
  42  *  This program demonstrates some characters of a
  43  *  stroke (vector) font.  The characters are represented
  44  *  by display lists, which are given numbers which
  45  *  correspond to the ASCII values of the characters.
  46  *  Use of glCallLists() is demonstrated.
  47  */
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include <GL/glut.h>
  51
  52 #define PT 1
  53 #define STROKE 2
  54 #define END 3
  55
  56 typedef struct charpoint {
  57     GLfloat   x, y;
  58     int    type;
  59 } CP;
  60
  61 CP Adata[] = {
  62     { 0, 0, PT}, {0, 9, PT}, {1, 10, PT}, {4, 10, PT},
  63     {5, 9, PT}, {5, 0, STROKE}, {0, 5, PT}, {5, 5, END}
  64 };
  65
  66 CP Edata[] = {
  67     {5, 0, PT}, {0, 0, PT}, {0, 10, PT}, {5, 10, STROKE},
  68     {0, 5, PT}, {4, 5, END}
  69 };
  70
  71 CP Pdata[] = {
  72     {0, 0, PT}, {0, 10, PT},  {4, 10, PT}, {5, 9, PT}, {5, 6, PT},
  73     {4, 5, PT}, {0, 5, END}
  74 };
  75
  76 CP Rdata[] = {
  77     {0, 0, PT}, {0, 10, PT},  {4, 10, PT}, {5, 9, PT}, {5, 6, PT},
  78     {4, 5, PT}, {0, 5, STROKE}, {3, 5, PT}, {5, 0, END}
  79 };
  80
  81 CP Sdata[] = {
  82     {0, 1, PT}, {1, 0, PT}, {4, 0, PT}, {5, 1, PT}, {5, 4, PT},
  83     {4, 5, PT}, {1, 5, PT}, {0, 6, PT}, {0, 9, PT}, {1, 10, PT},
  84     {4, 10, PT}, {5, 9, END}
  85 };
  86
  87 /*  drawLetter() interprets the instructions from the array
  88  *  for that letter and renders the letter with line segments.
  89  */
  90 static void drawLetter(CP *l)
  91 {
  92     glBegin(GL_LINE_STRIP);
  93     for (;;) {
  94         switch (l->type) {
  95             case PT:
  96                 glVertex2fv(&l->x);
  97                 break;
  98             case STROKE:
  99                 glVertex2fv(&l->x);
 100                 glEnd();
 101                 glBegin(GL_LINE_STRIP);
 102                 break;
 103             case END:
 104                 glVertex2fv(&l->x);
 105                 glEnd();
 106                 glTranslatef(8.0, 0.0, 0.0);
 107                 return;
 108         }
 109         l++;
 110     }
 111 }
 112
 113 /*  Create a display list for each of 6 characters      */
 114 static void myinit (void)
 115 {
 116     GLuint base;
 117
 118     glShadeModel (GL_FLAT);
 119
 120     base = glGenLists (128);
 121     glListBase(base);
 122     glNewList(base+'A', GL_COMPILE); drawLetter(Adata); glEndList();
 123     glNewList(base+'E', GL_COMPILE); drawLetter(Edata); glEndList();
 124     glNewList(base+'P', GL_COMPILE); drawLetter(Pdata); glEndList();
 125     glNewList(base+'R', GL_COMPILE); drawLetter(Rdata); glEndList();
 126     glNewList(base+'S', GL_COMPILE); drawLetter(Sdata); glEndList();
 127     glNewList(base+' ', GL_COMPILE); glTranslatef(8.0, 0.0, 0.0); glEndList();
 128 }
 129
 130 char *test1 = "A SPARE SERAPE APPEARS AS";
 131 char *test2 = "APES PREPARE RARE PEPPERS";
 132
 133 static void printStrokedString(char *s)
 134 {
 135     GLsizei len = (GLsizei) strlen(s);
 136     glCallLists(len, GL_BYTE, (GLbyte *)s);
 137 }
 138
 139 static void display(void)
 140 {
 141     glClear(GL_COLOR_BUFFER_BIT);
 142     glColor3f(1.0, 1.0, 1.0);
 143     glPushMatrix();
 144     glScalef(2.0, 2.0, 2.0);
 145     glTranslatef(10.0, 30.0, 0.0);
 146     printStrokedString(test1);
 147     glPopMatrix();
 148     glPushMatrix();
 149     glScalef(2.0, 2.0, 2.0);
 150     glTranslatef(10.0, 13.0, 0.0);
 151     printStrokedString(test2);
 152     glPopMatrix();
 153     glFlush();
 154 }
 155
 156 static void reshape(GLsizei w, GLsizei h)
 157 {
 158     glViewport(0, 0, w, h);
 159     glMatrixMode(GL_PROJECTION);
 160     glLoadIdentity();
 161     glOrtho(0.0, (GLdouble)w, 0.0, (GLdouble)h, -1.0, 1.0);
 162     glMatrixMode(GL_MODELVIEW);
 163     glLoadIdentity();
 164 }
 165
 166 static void
 167 key(unsigned char k, int x, int y)
 168 {
 169   switch (k) {
 170   case 27:  /* Escape */
 171     exit(0);
 172     break;
 173   default:
 174     return;
 175   }
 176   glutPostRedisplay();
 177 }
 178
 179 /*  Main Loop
 180  *  Open window with initial window size, title bar,
 181  *  RGBA display mode, and handle input events.
 182  */
 183 int main(int argc, char** argv)
 184 {
 185     glutInit(&argc, argv);
 186     glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
 187     glutInitWindowSize (440, 120);
 188     glutCreateWindow (argv[0]);
 189     myinit ();
 190     glutDisplayFunc(display);
 191     glutReshapeFunc(reshape);
 192     glutKeyboardFunc(key);
 193     glutMainLoop();
 194     return 0;             /* ANSI C requires main to return int. */
 195 }