using namespace std;
#include "asn2.h"
#include<math.h>


// Function to make a color based on RGB values:
Glib::RefPtr<Gdk::GC> darea::makecolorgc(short r, short g, short b)
{
  Glib::RefPtr<Gdk::Window> win = get_window();
  Glib::RefPtr<Gdk::GC> some_gc = Gdk::GC::create(win);
  Gdk::Color some_color;
  Glib::RefPtr<Gdk::Colormap> some_colormap = get_default_colormap();
  some_color.set_red(r);
  some_color.set_green(g);
  some_color.set_blue(b);
  some_colormap->alloc_color(some_color);
  some_gc->set_foreground(some_color);
  return some_gc;
}

// Function to display text
void darea::displaytext(const char *c,
		 Glib::RefPtr<Gdk::GC> colorgc,
		 int x, int y
                 )
{
  Glib::RefPtr<Gdk::Window> win = get_window();
  Glib::RefPtr<Pango::Layout> pangolayout = create_pango_layout(c);
  win->draw_layout(colorgc, x, y, pangolayout);
}

// function to force a s second delay  (controls animation speed)
void delayforsecs(double s)
{ int x = 3;
  Glib::Timer t;
  t.start();
  while (t.elapsed()<s) { x++; x--; }
  t.stop();
}

dwindow::dwindow() : canvas(1024,768)  // default size only
{
  add(canvas);
  show_all_children();
  //  canvas.iroutine();
}

// Drawing area constructor:
darea::darea(int x, int y) : DrawingArea(), box(UW,UH,UD,0.5,220)
{
  width = box.wwidth();  height = box.wheight();
  set_size_request(width,height);
  win = NULL;
  i = 1;
  started = false;
}

int main(int argc, char **argv)
{
  Gtk::Main mr(argc, argv);
  dwindow thewindow;
  mr.run(thewindow);
  return 0;
}

//////  You shouldn't have to touch anything above this line.



void darea::iroutine()  // initialization routine
{
     win = get_window();
     dbuffer = Gdk::Pixmap::create(win,width,height,-1); // double buffer
     blackgc = get_style()->get_black_gc();
     whitegc = get_style()->get_white_gc();
     ggc = makecolorgc(0,65535,0);  // Green GC
     rgc = makecolorgc(65535,0,0);  // Red GC
     bgc = makecolorgc(0,0,65535);  // Blue GC
     dbuffer->draw_rectangle(blackgc, true, 0, 0, width, height);      
     box.drawbox(dbuffer,0,0,0,799,599,399,rgc);  
     started = true;
     i = 0;

     ///// you may want to initialize your body objects here

} // iroutine 


// Main event loop: 
bool darea::on_expose_event(GdkEventExpose *event)
{ 
  if (!started) iroutine();
  animate();  
  return true; 
}

// Called during each execution of on_expose_event.  Each call to animate
// should produce one complete frame of animation.
void darea::animate() 
{
      delayforsecs(1.0);  // 1 second delay between frames
      // clear and draw static background:
      dbuffer->draw_rectangle(blackgc, true, 0, 0, width, height);      
      box.drawbox(dbuffer,0,0,0,799,599,399,bgc);  


      ////////////////// Do some drawings:
      box.drawline(dbuffer,0,0,0,500,500,350,rgc);  // red line
      box.drawcircle(dbuffer, false, 280, 120, 150,40,bgc); // blue outline
      box.drawcircle(dbuffer, true, 80, 120, 15+i, 50,ggc); // true=filled
      i += 10;  // moves circle on next frame  (i is non-local var)
      /////////////////


      //  draw buffer to screen:     
      win->draw_drawable(blackgc,dbuffer,0,0,0,0,width,height);
      // "invalidate" signals the window app to redraw itself:
      Gdk::Rectangle r(0,0,width,height);
      win->invalidate_rect(r,true);
} // onexposeevent


void body::calcforce(body *B) // effect of B on this body 
{
  double d2, dx, dy, dist, sm, sz, dz;
  double accAX, accAY, accAZ, deeper; // accelerations
  dx = B->xcord - xcord;
  dy = B->ycord - ycord;
  dz = B->zcord - zcord;
  d2 = (dx*dx) + (dy*dy) + (dz*dz); 
  if (d2==0) d2=1e-100;    // avoid division by zero
  dist = sqrt(d2);         // distance 
  // scale into unit vector
  dx = dx/dist;  dy = dy/dist;   dz = dz/dist;
  // dx,dy,dz now represents the direction of acceleration
  // calculate acceleration vector:
  accAX = dx * (G*B->mass)/d2; 
  accAY = dy * (G*B->mass)/d2; 
  accAZ = dz * (G*B->mass)/d2;
  // change velocity vector according to acceleration:
  xvel += accAX * UTIME;
  yvel += accAY * UTIME;
  zvel += accAZ * UTIME;
  // position coords will be changed during simulation, since
  // we still have to calculate the effect of other bodies on this one
}  // calcforce


/* compile:
g++ boxworld.o asn2.cpp -o gravity `pkg-config gtkmm-2.0 --cflags --libs`
*/