OpenGLUT 0.6.3 development - OpenGLUT: stroke.c File Reference
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# stroke.c File Reference

## Detailed Description

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.

    /* Copyright (c) Mark J. Kilgard, 1994. */

    /*
     * (c) Copyright 1993, 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     * Unpublished-- rights reserved under the copyright laws of the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(TM) is a trademark of Silicon Graphics, Inc.
     */

    #include <GL/openglut.h>
    #include <stdlib.h>
    #include <string.h>

    #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.
     */
    void drawLetter(CP *l)
    {
        glBegin(GL_LINE_STRIP);
        for (;;) {
        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  */
    void myinit (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";

    void printStrokedString(char *s)
    {
        GLsizei len = (GLsizei) 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();
    }

    static void reshape(GLsizei w, GLsizei h)
    {
        glViewport(0, 0, w, h);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glOrtho(0.0, (GLdouble)w, 0.0, (GLdouble)h, -1.0, 1.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
    }

    static void
    key(unsigned char k, int x, int y)
    {
      switch (k) {
      case 27:  /* Escape */
        exit(0);
        break;
      default:
        return;
      }
      glutPostRedisplay();
    }

    /*  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 (argv[0]);
        myinit ();
        glutDisplayFunc(display);
        glutReshapeFunc(reshape);
        glutKeyboardFunc(key);
        glutMainLoop();
        return 0;             /* ANSI C requires main to return int. */
    }

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