www.pudn.com > openglbk.rar > stroke.c

/* 
 * Copyright (c) 1993-1999, Silicon Graphics, Inc. 
 * ALL RIGHTS RESERVED  
 * Permission to use, copy, modify, and distribute this software for  
 * any purpose and without fee is hereby granted, provided that the above 
 * copyright notice appear in all copies and that both the copyright notice 
 * and this permission notice appear in supporting documentation, and that  
 * the name of Silicon Graphics, Inc. not be used in advertising 
 * or publicity pertaining to distribution of the software without specific, 
 * written prior permission.  
 * 
 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" 
 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR 
 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON 
 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT, 
 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY 
 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, 
 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF 
 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN 
 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON 
 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE 
 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE. 
 *  
 * US Government Users Restricted Rights  
 * Use, duplication, or disclosure by the Government is subject to 
 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph 
 * (c)(1)(ii) of the Rights in Technical Data and Computer Software 
 * clause at DFARS 252.227-7013 and/or in similar or successor 
 * clauses in the FAR or the DOD or NASA FAR Supplement. 
 * Unpublished-- rights reserved under the copyright laws of the 
 * United States.  Contractor/manufacturer is Silicon Graphics, 
 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311. 
 * 
 * OpenGL(R) is a registered trademark of Silicon Graphics, Inc. 
 */ 
 
/* 
 *  stroke.c  
 *  This program demonstrates some characters of a  
 *  stroke (vector) font.  The characters are represented 
 *  by display lists, which are given numbers which  
 *  correspond to the ASCII values of the characters. 
 *  Use of glCallLists() is demonstrated. 
 */ 
#include  
#include  
#include  
 
#define PT 1 
#define STROKE 2 
#define END 3 
 
typedef struct charpoint { 
   GLfloat   x, y; 
   int    type; 
} CP; 
 
CP Adata[] = { 
   { 0, 0, PT}, {0, 9, PT}, {1, 10, PT}, {4, 10, PT},  
   {5, 9, PT}, {5, 0, STROKE}, {0, 5, PT}, {5, 5, END} 
}; 
 
CP Edata[] = { 
   {5, 0, PT}, {0, 0, PT}, {0, 10, PT}, {5, 10, STROKE}, 
   {0, 5, PT}, {4, 5, END} 
}; 
 
CP Pdata[] = { 
   {0, 0, PT}, {0, 10, PT},  {4, 10, PT}, {5, 9, PT}, {5, 6, PT},  
   {4, 5, PT}, {0, 5, END} 
}; 
 
CP Rdata[] = { 
   {0, 0, PT}, {0, 10, PT},  {4, 10, PT}, {5, 9, PT}, {5, 6, PT},  
   {4, 5, PT}, {0, 5, STROKE}, {3, 5, PT}, {5, 0, END} 
}; 
 
CP Sdata[] = { 
   {0, 1, PT}, {1, 0, PT}, {4, 0, PT}, {5, 1, PT}, {5, 4, PT},  
   {4, 5, PT}, {1, 5, PT}, {0, 6, PT}, {0, 9, PT}, {1, 10, PT},  
   {4, 10, PT}, {5, 9, END} 
}; 
 
/*  drawLetter() interprets the instructions from the array 
 *  for that letter and renders the letter with line segments. 
 */ 
static void drawLetter(CP *l) 
{ 
   glBegin(GL_LINE_STRIP); 
   while (1) { 
      switch (l->type) { 
         case PT: 
            glVertex2fv(&l->x); 
            break; 
         case STROKE: 
            glVertex2fv(&l->x); 
            glEnd(); 
            glBegin(GL_LINE_STRIP); 
            break; 
         case END: 
            glVertex2fv(&l->x); 
            glEnd(); 
            glTranslatef(8.0, 0.0, 0.0); 
            return; 
      } 
      l++; 
   } 
} 
 
/*  Create a display list for each of 6 characters	*/ 
static void init (void) 
{ 
   GLuint base; 
 
   glShadeModel (GL_FLAT); 
 
   base = glGenLists (128); 
   glListBase(base); 
   glNewList(base+'A', GL_COMPILE); drawLetter(Adata); glEndList(); 
   glNewList(base+'E', GL_COMPILE); drawLetter(Edata); glEndList(); 
   glNewList(base+'P', GL_COMPILE); drawLetter(Pdata); glEndList(); 
   glNewList(base+'R', GL_COMPILE); drawLetter(Rdata); glEndList(); 
   glNewList(base+'S', GL_COMPILE); drawLetter(Sdata); glEndList(); 
   glNewList(base+' ', GL_COMPILE); glTranslatef(8.0, 0.0, 0.0); glEndList(); 
} 
 
char *test1 = "A SPARE SERAPE APPEARS AS"; 
char *test2 = "APES PREPARE RARE PEPPERS"; 
 
static void printStrokedString(char *s) 
{ 
   GLsizei len = strlen(s); 
   glCallLists(len, GL_BYTE, (GLbyte *)s); 
} 
 
void display(void) 
{ 
   glClear(GL_COLOR_BUFFER_BIT); 
   glColor3f(1.0, 1.0, 1.0); 
   glPushMatrix(); 
   glScalef(2.0, 2.0, 2.0); 
   glTranslatef(10.0, 30.0, 0.0); 
   printStrokedString(test1); 
   glPopMatrix(); 
   glPushMatrix(); 
   glScalef(2.0, 2.0, 2.0); 
   glTranslatef(10.0, 13.0, 0.0); 
   printStrokedString(test2); 
   glPopMatrix(); 
   glFlush(); 
} 
 
void reshape(int w, int h) 
{ 
   glViewport(0, 0, (GLsizei) w, (GLsizei) h); 
   glMatrixMode (GL_PROJECTION); 
   glLoadIdentity (); 
   gluOrtho2D (0.0, (GLdouble) w, 0.0, (GLdouble) h); 
} 
 
void keyboard(unsigned char key, int x, int y) 
{ 
   switch (key) { 
      case ' ': 
         glutPostRedisplay(); 
         break; 
      case 27: 
         exit(0); 
   } 
} 
 
/*  Main Loop 
 *  Open window with initial window size, title bar,  
 *  RGBA display mode, and handle input events. 
 */ 
int main(int argc, char** argv) 
{ 
   glutInit(&argc, argv); 
   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); 
   glutInitWindowSize (440, 120); 
   glutCreateWindow ("stroke"); 
   init (); 
   glutReshapeFunc(reshape); 
   glutKeyboardFunc(keyboard); 
   glutDisplayFunc(display); 
   glutMainLoop(); 
   return 0; 
}