/* way cool cube */

/* cc wc_cube.c -o wc_cube -L/usr/lib -L/usr/X11R6/lib -lX11 -lGL -lGLU -lm */

#include <X11/Xlib.h> 
#include <stdio.h>
#include <math.h>
#include <GL/gl.h>
#include <GL/glx.h>

int vattrib [] = {
   GLX_RGBA,
   GLX_RED_SIZE, 8,
   GLX_GREEN_SIZE, 8,
   GLX_BLUE_SIZE, 8,
   GLX_DEPTH_SIZE, 1,  /* at least 1 means get largest */
   None
};

Display *display;
Window rootw, win;


main (int argc, char **argv)

{
   XSizeHints whisper;
   XEvent report;
   unsigned long eventmask;
   int screen, width, height;
   XVisualInfo *pgob;
   XSetWindowAttributes attrib;
   GLXContext ctx;
   XColor white, black;
   int bsz;

   if ((display = XOpenDisplay (NULL)) == NULL) {
	fprintf(stderr,"can't open\n");
	exit(1);
   }

   screen = DefaultScreen (display);
   width = 512;
   height = 512;
   rootw = RootWindow (display, screen);

   pgob = glXChooseVisual (display, screen, vattrib);
   attrib.colormap = XCreateColormap (display, rootw, pgob->visual, AllocNone);

   white.red = 0xffff;
   white.green = 0xffff;
   white.blue = 0xffff;

   black.red = 0;
   black.green = 0;
   black.blue = 0;

   XAllocColor(display,attrib.colormap,&white);
   XAllocColor(display,attrib.colormap,&black);

   attrib.background_pixel = white.pixel;
   attrib.border_pixel = black.pixel;

   /* create output window with black border and white background;
      upper left corner will be at (0,0); border size at this level 
      is overriden by window manager, so just make it 0 */

   bsz=0;
   win = XCreateWindow (display, rootw, 0, 0, width, height, bsz, pgob->depth,
          InputOutput, pgob->visual, CWBorderPixel | CWColormap | CWBackPixel, 
          &attrib);

   /* attach OpenGL output to selected window */
   ctx = glXCreateContext (display, pgob, NULL, True);
   glXMakeCurrent (display, win, ctx);

   /* whisper hints */
   whisper.flags = PSize | PPosition;
   whisper.width = width;
   whisper.height = height;
   XSetStandardProperties (display, win, "win", "win_icon", None, argv, argc, 
                           &whisper);

   eventmask = ExposureMask | KeyPressMask;
   XSelectInput (display, win, eventmask);

   XMapWindow (display, win);

   /* wait on expose */
   XNextEvent (display, &report);
   while (report.type != Expose) {
      printf ("do wah\n");
      XNextEvent (display,&report);
   }

   while (1) {
      switch (report.type) {
         case Expose:
                         do_cube ();
                         break;

         case KeyPress:
                         glXDestroyContext (display, ctx);
                         XCloseDisplay (display);
                         exit (0);

         default:
                         sleep (1);
      }

      XNextEvent(display,&report);
   }
}


struct point {
   float x;
   float y;
   float z;
};


do_cube ()

{
   struct point eyept, viewpt;

   /* dark gray background */
   glClearColor (0.3, 0.3, 0.3, 0.0);
   glClear (GL_COLOR_BUFFER_BIT);

   /* call for wireframe */
   glPolygonMode (GL_FRONT,GL_LINE);
   glPolygonMode (GL_BACK,GL_LINE);

   /* fat yellow lines */
   glColor4f (1.0, 1.0, 0.0, 1.0);
   glLineWidth (2.0);

   /* carve out gob */
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
   gluPerspective (45.0, 1.0, 0.1, 20.0);

   /* draw pix at origin */
   glMatrixMode (GL_MODELVIEW);
   glLoadIdentity ();

   eyept.x = 2.5; eyept.y = 1.8; eyept.z = 2.0;
   viewpt.x = 0.0; viewpt.y = 0.0; viewpt.z = 0.0;

   gluLookAt(eyept.x, eyept.y, eyept.z, viewpt.x, viewpt.y, viewpt.z, 
             0.0, 1.0, 0.0);

   picasso ();
}


float vertex [8] [3] = {
   {0.0, 0.0, 0.0},
   {0.0, 1.0, 0.0},
   {1.0, 1.0, 0.0},
   {1.0, 0.0, 0.0},
   {0.0, 0.0, 1.0},
   {0.0, 1.0, 1.0},
   {1.0, 1.0, 1.0},
   {1.0, 0.0, 1.0}
};


int faces [6] [4] = {

   /* there are 6 faces; 4 verticies specify a face;
      looking from positive z axis we would have: */

   /* front face */
   {4, 5, 6, 7},

   /* back face */
   {3, 2, 1, 0},

   /* left side */
   {0, 1, 5, 4},

   /* right side */
   {7, 6, 2, 3},

   /* top */
   {5, 1, 2, 6},

   /* bottom */
   {0, 4, 7, 3}
};


picasso()

{
   int i;

   for (i = 0; i < 6; i++){

      glBegin (GL_QUADS); 
         glVertex3fv (vertex [faces [i] [0]]);
         glVertex3fv (vertex [faces [i] [1]]);
         glVertex3fv (vertex [faces [i] [2]]);
         glVertex3fv (vertex [faces [i] [3]]);
      glEnd ();
   }

   glFlush ();
}