import gtk			# Calls gtk module
import gtk.glade		# Calls gtk.glade module
import gtk.gtkgl		# Calls gtk.gtkgl module

from OpenGL.GL import *
from OpenGL.GLU import *


first_example = gtk.glade.XML( "first_example.glade")   # Calls the file and
							# "Allows dynamic loading of user interfaces from XML descriptions." 
							# (from Glade reference http://www.pygtk.org/docs/pygtk/class-gladexml.html)

def polyline( vertexes_list, closed = False):
	if closed:
		glBegin( GL_LINE_LOOP )
	else:
		glBegin( GL_LINE_STRIP )
	
	for vertex in vertexes_list:
		glVertex3f( vertex[0], vertex[1], 0 )
	
	glEnd()
	
class DrawArea(gtk.DrawingArea, gtk.gtkgl.Widget):
	def __init__(self):
		gtk.DrawingArea.__init__(self)	# Calls gtk.DrawingArea initializer
		
		self.set_events(gtk.gdk.BUTTON_MOTION_MASK | gtk.gdk.KEY_PRESS_MASK | gtk.gdk.KEY_RELEASE_MASK|                   #eventi da gestire (di cui tenere aperta la "porta")
	                        gtk.gdk.POINTER_MOTION_MASK | gtk.gdk.BUTTON_RELEASE_MASK|
	                        gtk.gdk.BUTTON_PRESS_MASK |  gtk.gdk.SCROLL_MASK)    

	        display_mode = (gtk.gdkgl.MODE_RGB | gtk.gdkgl.MODE_DOUBLE)
		
		try:                              
	            glconfig = gtk.gdkgl.Config(mode=display_mode)
	        except gtk.gdkgl.NoMatches:
	            display_mode &= ~gtk.gdkgl.MODE_SINGLE
	            glconfig = gtk.gdkgl.Config(mode = display_mode) 
	        self.set_gl_capability(glconfig)
	        self.set_events(gtk.gdk.BUTTON_MOTION_MASK | gtk.gdk.KEY_PRESS_MASK | gtk.gdk.KEY_RELEASE_MASK|                   #eventi da gestire (di cui tenere aperta la "porta")
                        gtk.gdk.POINTER_MOTION_MASK | gtk.gdk.BUTTON_RELEASE_MASK|
                        gtk.gdk.BUTTON_PRESS_MASK |  gtk.gdk.SCROLL_MASK)   
  		self.connect( "expose_event", self.on_expose_event )
  		self.connect( "realize", self.on_realize )
  		self.connect( "configure_event", self.on_configure_event )
  		
        def chiudi_gui(self, widget, event):
        	print "aho"
        	gtk.main_quit()
        
        
        
        def on_configure_event(self, *args):

	        gldrawable = self.get_gl_drawable()
	        glcontext = self.get_gl_context()
	        gldrawable.gl_begin(glcontext)      

            	glViewport(0, 0, 1000, 800)
    
		gluLookAt(0.0,0.0,0.5, 0.0,0.0,0.0, 0.0, 1.0, 0.0)
			
	def on_realize(self,*args):
	        """ Serve per settare le misure dell'area da disegno,la modalita' di visualizzazione, nel nostro caso una tavola 2D"""

	        gldrawable = self.get_gl_drawable()       # Obtain a reference to the Grafica drawable
	        glcontext = self.get_gl_context()         # and rendering context.
	        
	        if not gldrawable.gl_begin(glcontext):   # inizio dei comandi Grafica
	            return
	        
	        glClearColor(1.0, 1.0, 1.0, 1.0)
	        glMatrixMode(GL_PROJECTION)
	        glLoadIdentity()
	        

	        glOrtho( -40, 40, -30, 30, -1, 1 )

	        gldrawable.gl_end()                       #fine dei comandi Grafica
      
	def on_expose_event(self, *args):
	        """ Richiama la funzione display e svuota sul video tutto quello che e' nei buffer della scheda grafica, per disegnarlo"""
	        gldrawable = self.get_gl_drawable()
	        glcontext  = self.get_gl_context()
	        gldrawable.gl_begin(glcontext)
	        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
	        glMatrixMode(GL_MODELVIEW)
	        glLoadIdentity()

	        self.display()

	        gldrawable.swap_buffers()
	        gldrawable.gl_end()
	        
	def display(self):

		glClearColor(0,0,0,0)
            	glClear(GL_COLOR_BUFFER_BIT)
            	glColor3f(1,1,0)
		polyline( [ ( -10, -10 ), ( 10, -10 ), ( 10, 10 ), ( -10, 10 ) ], closed = True )
		
def chiudi_gui(widget, event):
	gtk.main_quit()
	
area = DrawArea()

main = first_example.get_widget("main_window")
main.connect( "delete_event", chiudi_gui )

box = first_example.get_widget("box_opengl")
box.pack_start(area)  
 
main.maximize()
main.set_title("First example")
main.show_all()

	        
gtk.main()