#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.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.
 */
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();
}

const char *test1 = "A SPARE SERAPE APPEARS AS";
const 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((char *)test1);
    glPopMatrix();
    glPushMatrix();
    glScalef(2.0, 2.0, 2.0);
    glTranslatef(10.0, 13.0, 0.0);
    printStrokedString((char *)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);
    }
}

int main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(440, 120);
    glutCreateWindow(argv[0]);
    init();
    glutReshapeFunc(reshape);
    glutKeyboardFunc(keyboard);
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;
}