#!/usr/bin/perl -w
use strict;
use warnings;

use OpenGL qw/ :all /;

use constant R30D => 0.523598776;

eval {glutInit(); 1} or die qq
{
This requires GLUT.
};

glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH | GLUT_ALPHA);
glutInitWindowSize(500, 500);

my $Window_ID = glutCreateWindow( "Open Gl Window" );

# Register the callback function to do the drawing.
glutDisplayFunc(\&cbRenderScene);
# If there's nothing to do, draw.
glutIdleFunc(\&cbRenderScene);
# It's a good idea to know when our window's resized.
glutReshapeFunc(\&resizeEvent);

# And let's get some input.
# glutKeyboardFunc(\&cbKeyPressed);
# glutSpecialFunc(\&cbSpecialKeyPressed);
# glutPassiveMotionFunc(\&mouseMove);
# glutMotionFunc(\&mouseMove);
# glutMouseFunc(\&mouseClick);


# Pass off control to OpenGL.
# Above functions are called as appropriate.
glutMainLoop();

exit 0;

sub resizeEvent
{
	my ($Width, $Height) = @_;

	print "Resize: $Width, $Height\n";
	
	# Let's not core dump, no matter what.
	$Height = 1 if ($Height <1);

	glViewport(0, 0, $Width, $Height);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(45.0,$Width/$Height,0.1,100.0);

	glMatrixMode(GL_MODELVIEW);

	$main::window_Width  = $Width;
	$main::window_Height = $Height;
}

sub cbRenderScene
{
	eval {do 'drawframe.pl';};
	print $@ . "\r";
	
	# Take a quick nap to avoid wasting CPU
	select (undef,undef,undef,0.1);
}