#!perl
use strict;
use warnings;
use Alien::FLTK;
use ExtUtils::CBuilder;
my $CC     = ExtUtils::CBuilder->new();
my $source = 'gl_hello_world.cxx';
open(my $FH, '>', $source) || die '...';
syswrite($FH, <<'') || die '...'; close $FH;
#line 11 "0002_gl.pl"
#include <fltk/gl.h>
#include <fltk/GlWindow.h>
#include <fltk/run.h>
using namespace fltk;
float theta     = 0.0f;
float speed     = 0.0f;
int   direction = -1;
int   range     = 12;
class MyGlWindow : public GlWindow {
public:
    MyGlWindow( int x, int y, int w, int h ) :
            GlWindow( x, y, w, h, "'Hello, World' ...OpenGL style" ) { }
private:
    void draw( ) {
        if ( !valid() ) {
            valid( 1 );
            glLoadIdentity();
            glViewport( 0, 0, w(), h() );
        }
        glClearColor( 0, 0, 0, 0 );
        glClear ( GL_COLOR_BUFFER_BIT );
        glPushMatrix ();
        glRotatef ( theta, 0.0f, 0.0f, 1.0f );
        glBegin ( GL_TRIANGLES );
        glColor3f ( 1.0f, 0.0f, 0.0f );
        glVertex2f ( 0.0f, 1.0f );
        glColor3f ( 0.0f, 1.0f, 0.0f );
        glVertex2f ( 0.87f, -0.5f );
        glColor3f ( 0.0f, 0.0f, 1.0f );
        glVertex2f ( -0.87f, -0.5f );
        glEnd();
        glPopMatrix();
        theta += speed;
        glsetcolor( fltk::WHITE );
        glsetfont( labelfont(), labelsize() * 3 );
        gldrawtext( "Hello, World!", -.4, 0 );
    };
};
MyGlWindow* gl = new MyGlWindow( 100, 100, 500, 500 );
void tick( void * v ) {
    if ( speed > range ) {
        direction = -1;
    }
    else if ( speed < -range ) {
        direction = 1;
    }
    speed += ( 0.1 * direction );
    gl->redraw();
    repeat_timeout( 0.01, tick, v );
}
int main( int argc, char **argv ) {
    gl->show();
    add_timeout( 0.01, tick, &gl );
    return run();
}

my $obj = $CC->compile(source               => $source,
                       extra_compiler_flags => Alien::FLTK->cxxflags());
my $exe = $CC->link_executable(
                          objects            => $obj,
                          extra_linker_flags => [Alien::FLTK->ldflags(qw[gl])]
);
printf system('./' . $exe) ? 'Aww...' : 'Yay! %s bytes', -s $exe;
END { unlink grep defined, $source, $obj, $exe; }

=pod

=head1 Author

Sanko Robinson <sanko@cpan.org> - http://sankorobinson.com/

CPAN ID: SANKO

=head1 License and Legal

Copyright (C) 2009 by Sanko Robinson E<lt>sanko@cpan.orgE<gt>

This program is free software; you can redistribute it and/or modify it under
the terms of The Artistic License 2.0. See the F<LICENSE> file included with
this distribution or http://www.perlfoundation.org/artistic_license_2_0.  For
clarification, see http://www.perlfoundation.org/artistic_2_0_notes.

When separated from the distribution, all POD documentation is covered by the
Creative Commons Attribution-Share Alike 3.0 License. See
http://creativecommons.org/licenses/by-sa/3.0/us/legalcode.  For
clarification, see http://creativecommons.org/licenses/by-sa/3.0/us/.

=for git $Id: 0003_gl.pl e048451 2009-09-02 03:23:06Z sanko@cpan.org $

=cut
