/******************************************************************************
* FILE:   animation_menu.cc
*         A simple animation in a window with a menu.
*
* Author: Dana Vrajitoru, IUSB
* Class:  C481 B581 Computer Graphics
******************************************************************************/

#include <gnome.h>
#include <math.h>
#include <stdlib.h>
#include "menu_handle.h"

static struct ballStruct {
  double x, y;
  double xVelocity, yVelocity;
} ball[5];

/* a callback for the buttons */
static void a_callback(GtkWidget *button, gpointer data)
{
  /*just print a string so that we know we got there*/
  g_print("Inside Callback\n");
}

/*
GnomeUIInfo file_menu[] = {
  GNOMEUIINFO_MENU_EXIT_ITEM(gtk_main_quit,NULL),
  GNOMEUIINFO_END
};

GnomeUIInfo some_menu[] = {
  GNOMEUIINFO_ITEM_NONE("_Menuitem","Just a menuitem",
			a_callback),
  GNOMEUIINFO_SEPARATOR,
  GNOMEUIINFO_ITEM_NONE("M_enuitem2","Just a menuitem",
			a_callback),
  GNOMEUIINFO_END
};

GnomeUIInfo menubar[] = {
  GNOMEUIINFO_MENU_FILE_TREE(file_menu),
  GNOMEUIINFO_SUBTREE("_Some menu",some_menu),
  GNOMEUIINFO_END
};
*/

GnomeUIInfo file_menu[2], some_menu[4], menubar[3];
void makeMenus()
{
  Menu_add_exit(file_menu, 0);
  Menu_end(file_menu, 1);

  Menu_add_item_simple(some_menu, 0, 
		       "_Menuitem","Just a menuitem", a_callback);
  Menu_add_separator(some_menu, 1);
  Menu_add_item_simple(some_menu, 2, 
		       "M_enuitem2","Just a menuitem", a_callback);
  Menu_end(some_menu, 3);

  Menu_add_file(menubar, file_menu);
  Menu_add_subtree(menubar, 1, some_menu, "_Some menu");
  Menu_end(menubar, 2);
}

gint eventDelete(GtkWidget *widget, GdkEvent *event, gpointer data);
gint eventDestroy(GtkWidget *widget, GdkEvent *event, gpointer data);
gint nextFrame(gpointer data);
void newBall(ballStruct &b);
void nextBall(ballStruct &b);

const int WIDTH=400, HEIGHT=300, GRAVITY=0.8,
  RADIUS=5, DIAMETER=RADIUS*2, INTERVAL=30;

int main(int argc, char **argv)
{
  int i;
  GtkWidget *app;
  GtkWidget *area;
  
  gnome_init("animation", "1.0", argc, argv);
  makeMenus();
  app = gnome_app_new("animation", "Drawing Area Animation");
  gtk_container_set_border_width(GTK_CONTAINER(app), 3);
  gtk_signal_connect(GTK_OBJECT(app), "delete_event", 
		     GTK_SIGNAL_FUNC(eventDelete), NULL);
  gtk_signal_connect(GTK_OBJECT(app), "destroy", 
		     GTK_SIGNAL_FUNC(eventDestroy), NULL);

  area = gtk_drawing_area_new();
  gtk_widget_set_usize(area, WIDTH, HEIGHT);
  gnome_app_set_contents(GNOME_APP(app),area);
  /*create the menus for the application*/
  gnome_app_create_menus (GNOME_APP (app), menubar);

  gtk_timeout_add(INTERVAL, nextFrame, area);
  for (i=0; i<5; i++)
    newBall(ball[i]);

  gtk_widget_show_all(app);
  gtk_main();
  exit(0);
}

gint nextFrame(gpointer data)
{
  int i;
  static GdkPixmap *pixmap = NULL;
  GtkWidget *widget = (GtkWidget *)data;
  
  if (pixmap == NULL) {
    pixmap = gdk_pixmap_new(widget->window, WIDTH, HEIGHT, -1);
  }
  
  gdk_draw_rectangle(pixmap, widget->style->white_gc, 1, 0, 0, 
		     WIDTH, HEIGHT);

  for (i=0; i<5; i++) {
    nextBall(ball[i]);
    gdk_draw_arc(pixmap, widget->style->black_gc, 1,
		 (int)ball[i].x, (int)ball[i].y,
		 DIAMETER, DIAMETER, 0, 360*64);
  }
  
  gdk_draw_pixmap(widget->window, widget->style->black_gc, pixmap,
		  0, 0, 0, 0, WIDTH, HEIGHT);
  return(1);
}

void newBall(ballStruct &b)
{
  b.x = ((double)rand()*WIDTH)/RAND_MAX;
  b.y = (((double)rand()*HEIGHT)/RAND_MAX) - HEIGHT;
  do {
    b.xVelocity = ((double)rand()*10)/RAND_MAX;
    b.yVelocity = ((double)rand()*10)/RAND_MAX;
  } while (fabs(b.xVelocity) < 0.5);
}

void nextBall(ballStruct &b)
{
  if ((b.x < -DIAMETER) || (b.x > WIDTH)) {
    newBall(b);
    return;
  }
  if ((b.y + DIAMETER) >= HEIGHT) {
    if (b.yVelocity > 0)
      b.yVelocity = -b.yVelocity;
    b.yVelocity *= 0.9;
  }
  else {
    b.yVelocity += GRAVITY;
  }
  b.x += b.xVelocity;
  b.y += b.yVelocity;
}

gint eventDelete(GtkWidget *widget, GdkEvent *event, gpointer data)
{
  gtk_main_quit();
  return(0);
}

gint eventDestroy(GtkWidget *widget, GdkEvent *event, gpointer data)
{
  gtk_main_quit();
  return(0);
}