/*
 * A demonstration of using the GLXPixmap functions.  This program is in
 * the public domain.
 * Brian Paul
 */

/* modified with traces/etc for TransGaming by
 * David Hammerton
 * david@transgaming.com
 * 16 May, 2003
 * 
 * Modified by jpc 2006 
 * not using Shm 
 */

#include <GL/gl.h>
#include <GL/glx.h>
#include <stdio.h>
#include <stdlib.h>

#include <X11/extensions/XShm.h>
#include <sys/ipc.h>
#include <sys/shm.h>


static GC gc;
static int with_shm=0;

typedef struct
{
  GLXContext ctx;
  XVisualInfo *visinfo;
  Display *dpy;
  Window win;
  Pixmap pm;
  GLXPixmap glxpm;
  XShmSegmentInfo *shmseginfo;
  void *vidmem;
  int width, height;
} vidData;

static void make_rgb_window( vidData *ourData )
{
   int attrib[] = { GLX_RGBA,
		    GLX_RED_SIZE, 1,
		    GLX_GREEN_SIZE, 1,
		    GLX_BLUE_SIZE, 1,
		    None };
   int scrnum;
   XSetWindowAttributes attr;
   unsigned long mask;
   Window root;
   Window win;

   scrnum = DefaultScreen( ourData->dpy );
   root = RootWindow( ourData->dpy, scrnum );

   ourData->visinfo = glXChooseVisual( ourData->dpy, scrnum, attrib );
   if (!ourData->visinfo) {
      printf("Error: couldn't get an RGB, Double-buffered visual\n");
      exit(1);
   }

   /* window attributes */
   attr.background_pixel = 0;
   attr.border_pixel = 0;
   /* TODO: share root colormap if possible */
   attr.colormap = XCreateColormap( ourData->dpy, root, ourData->visinfo->visual, AllocNone);
   attr.event_mask = StructureNotifyMask | ExposureMask;
   mask = CWBackPixel | CWBorderPixel | CWColormap | CWEventMask;

   ourData->win = XCreateWindow( ourData->dpy, root, 0, 0, ourData->width, ourData->height,
				 0, ourData->visinfo->depth, InputOutput,
				 ourData->visinfo->visual, mask, &attr );

   /* make an X GC so we can do XCopyArea later */
   gc = XCreateGC( ourData->dpy, ourData->win, 0, NULL );
   ourData->ctx = glXCreateContext( ourData->dpy,ourData->visinfo, NULL, False );
}


static void make_pixmap( vidData *ourData)
{
  int i;
  GLXPixmap glxpm;
  Pixmap testpm;
  XWindowAttributes attr;

  for ( i = 0 ; i < 1000 ; i++)
    {
      /*
      ourData->ctx = glXCreateContext( ourData->dpy,ourData->visinfo, NULL, False );
      */
      ourData->pm = XCreatePixmap( ourData->dpy, ourData->win, ourData->width, ourData->height, 
				   ourData->visinfo->depth );
      XGetWindowAttributes( ourData->dpy, ourData->win, &attr );
      fprintf(stderr, "XPixmap created: %i\n", ourData->pm);
      XSync(ourData->dpy, 0);
      fprintf(stderr, "synced\n");
#if 0 /*   GLX_MESA_pixmap_colormap   */
      /* does not work */
      ourData->glxpm = glXCreateGLXPixmapMESA( ourData->dpy, ourData->visinfo, ourData->pm, attr.colormap );
      fprintf(stderr, "GLXPixmap created with Mesa: %i\n", ourData->glxpm);
#else
      /* This will work with Mesa too if the visual is TrueColor or DirectColor */
      ourData->glxpm = glXCreateGLXPixmap( ourData->dpy, ourData->visinfo, ourData->pm );
      fprintf(stderr, "GLXPixmap created without Mesa: %i\n", ourData->glxpm);
#endif
      XSync(ourData->dpy, 0);
      fprintf(stderr, "synced\n");
      glXMakeCurrent( ourData->dpy, ourData->glxpm, ourData->ctx ); /* XXXXXXXX */
      fprintf(stderr, "make current \n");
      XSync(ourData->dpy, 0);
      fprintf(stderr, "make current \n");
      /* 
      glXDestroyContext(ourData->dpy,ourData->ctx);
      */
      glXMakeCurrent( ourData->dpy, None, NULL);
      glXDestroyPixmap(ourData->dpy,ourData->glxpm);
      XFreePixmap(ourData->dpy,ourData->pm);
      XSync(ourData->dpy, 0);
      XSync(ourData->dpy, 0);
      fprintf(stderr, "synced\n");
    }

  ourData->pm = XCreatePixmap( ourData->dpy, ourData->win, ourData->width, ourData->height, 
			       ourData->visinfo->depth );
  ourData->glxpm = glXCreateGLXPixmap( ourData->dpy, ourData->visinfo, ourData->pm );
}

static void event_loop( vidData *ourData )
{
   XEvent event;

   while (1) {
      XNextEvent( ourData->dpy, &event );

      switch (event.type) {
	 case Expose:
	    fprintf(stderr, "Redraw (src: %i (%08x), dest: %i (%08x))\n", ourData->pm, ourData->pm,
                event.xany.window, event.xany.window);
	    /* copy the image from GLXPixmap to window */
	    XCopyArea( ourData->dpy, ourData->pm, event.xany.window,  /* src, dest */
		       gc, 0, 0, 300, 300,          /* gc, src pos, size */
		       0, 0 );                      /* dest pos */
        fprintf(stderr, "done\n");
        XSync(ourData->dpy, 0);
        fprintf(stderr, "synced\n");
	    break;
	 case ConfigureNotify:
	    /* nothing */
	    break;
      }
   }
}



int main( int argc, char *argv[] )
{

    int i;
   vidData ourData;

   ourData.width = ourData.height = 300;
   ourData.dpy = XOpenDisplay(NULL);

   make_rgb_window( &ourData );
   make_pixmap( &ourData );

   fprintf(stderr, "display: %p, pixmap (glx): %i, context: %i\n", ourData.dpy, ourData.pm, ourData.ctx);
   XSync(ourData.dpy, 0);
   fprintf(stderr, "synced\n");
   glXMakeCurrent( ourData.dpy, ourData.glxpm, ourData.ctx );
   fprintf(stderr, "make current\n");
   XSync(ourData.dpy, 0);
   fprintf(stderr, "synced\n");

   /* Render an image into the pixmap */
   glShadeModel( GL_FLAT );
   glClearColor( 0.5, 0.5, 0.5, 1.0 );
   glClear( GL_COLOR_BUFFER_BIT );
   glViewport( 0, 0, 300, 300 );
   glOrtho( -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 );
   glColor3f( 0.0, 1.0, 1.0 );
   glRectf( -0.75, -0.75, 0.75, 0.75 );
   glColor3f( 1.0, 0.0, 0.0 );
   glBegin(GL_LINES);
   glVertex2f ( -0.5, -0.5 );
   glVertex2f ( 0.5, 0.5 );
   glEnd();
   glFlush();

   fprintf(stderr, "drawn\n");
   XSync(ourData.dpy, 0);
   fprintf(stderr, "synced\n");
   
   if ( with_shm ) 
     for (i = 0; i < 300 * 50; i++)
       {
	 ((char *)ourData.shmseginfo->shmaddr)[i] = i;
       }
   
   /* when a redraw is needed we'll just copy the pixmap image to the window */

   fprintf(stderr, "window: %i\n", ourData.win);
   XMapWindow( ourData.dpy, ourData.win );
   fprintf(stderr, "mapped\n");
   XSync(ourData.dpy, 0);
   fprintf(stderr, "synced\n");

   event_loop( &ourData );
   return 0;
}