Dear Chromatic,
After a few week struggling you seem to be the only man on Earth who is aware of the picking technique in perl. I tried everything, the farest point I was able to get to is that my code syntactically seems to be good but does not work anyhow. I even returned to OpenGL module as I can not find functions is sdl::opengl, but it did not help on the problem. Please somehow help me: one possible method if I could see your working code and try to do the rest of myself, the other possibility would be if you take a glance on my false working code and make some remarks. What should I do?
heres is the not working code:
#!/usr/bin/perl

# This example exists in three different versions,
#  one using OpenGL.pm
#  one using SDL::OpenGL
#  one using PDL::Graphics::OpenGL (this one)
# It's main purpose is to show how different OpenGL-implementations in
+ perl
# differ.

#use strict;
use Gtk2 '-init';
use Gtk2::GLExt;
#use PDL::Graphics::OpenGL;
#use SDL::OpenGL;
use OpenGL qw/:all/;


# this is nothing, a better example should be created!
my $length = 20;
my $width = 12;
my $height = 8;

my $room_rot=0;

# a 3ds lista elkeszitese
draw();

main();

sub main {
    my $glconfig;

    my $window;
    my $vbox;
    my $drawing_area;
    my $button;

    # Init GtkGLExt.
    Gtk2::GLExt->init;

    # Try double-buffered visual
    $glconfig = Gtk2::Gdk::GLExt::Config->new_by_mode(['rgb', 'depth',
+ 'double']);

    unless( $glconfig )    {
        print "*** Cannot find the double-buffered visual.\n";
        print "*** Trying single-buffered visual.\n";

        # Try single-buffered visual
        $glconfig = Gtk2::Gdk::GLExt::Config->new_by_mode(['rgb', 'dep
+th']);

        unless( $glconfig )        {
                  print "*** No appropriate OpenGL-capable "
                 ." visual found.\n";
            exit 1;
        }
    }

    # Top-level window.
    $window = Gtk2::Window->new;
    $window->set_title ("Reflections");

    # Perform the resizes immediately if on win32
    $window->set_resize_mode ('immediate') if( $^O eq 'MSWin32' );

    # Get automatically redrawn if any of their children changed alloc
+ation.
    $window->set_reallocate_redraws (1);
    $window->signal_connect (delete_event => sub { Gtk2->main_quit; 1}
+);

    # VBox.
    $vbox = Gtk2::VBox->new (0, 0);
    $window->add($vbox);
    $vbox->show;

    # Drawing area for drawing OpenGL scene.
    $drawing_area = Gtk2::DrawingArea->new ();
    $drawing_area->set_size_request (640, 512);

    # Set OpenGL-capability to the widget.
    $drawing_area->set_gl_capability ($glconfig, undef, 1, 'rgba-type'
+);
    $drawing_area->signal_connect_after (realize => \&realize);
    $vbox->pack_start ($drawing_area, 1, 1, 0);
    $drawing_area->show;

    # Simple quit button.
    $button = Gtk2::Button->new ("_Quit");
    $button->signal_connect (clicked => sub { 
        #for the quit button, the hit check is examined
        pickSquares();
        #Gtk2->main_quit; 
    });
    $vbox->pack_start ($button, 0, 0, 0);
    $button->show;

    # Show window.
    $window->show;
    Glib::Timeout->add( 30, \&draw_scene, $drawing_area );

    # Main loop.
    Gtk2->main;

    return 0;
}

sub realize {
    my $widget = shift;
    my $data = shift;

    my $glcontext = $widget->get_gl_context;
    my $gldrawable = $widget->get_gl_drawable;

    # OpenGL BEGIN
    return unless( $gldrawable->gl_begin ($glcontext) );

    my @LightAmbient = ( 0.5, 0.5, 0.5, 1.0 );
    my @LightDiffuse = ( 1.0, 1.0, 1.0, 1.0 );
    my @LightPosition = ( 0.0, 0.0, 2.0, 1.0 );

    my $alloc = $widget->allocation;
    glViewport(0, 0, $alloc->width, $alloc->height);
    glShadeModel(GL_SMOOTH);
    glClearColor(0, 0, 0, 0);
    glClearDepth(1.0);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LEQUAL);
    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);

    glLightfv_p(GL_LIGHT1, GL_AMBIENT, @LightAmbient);
    glLightfv_p(GL_LIGHT1, GL_DIFFUSE, @LightDiffuse);
    glLightfv_p(GL_LIGHT1, GL_POSITION, @LightPosition);
    glEnable(GL_LIGHT1);

    glPolygonMode( GL_BACK, GL_FILL );
    glPolygonMode( GL_FRONT, GL_LINE );

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45.0,$alloc->width/$alloc->height,0.1,500.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    draw("GL_RENDER");
    $gldrawable->gl_end;
    # OpenGL END
}

sub pickSquares() {
    my $BUFSIZE=100;
    my @selectBuf=();
    my $hits;
    my @viewport=();
    my $x, $y;

    $x = 100;    #these would be the mouse coordinates once
    $y = 100;

    @viewport=OpenGL::glGetIntegerv_p(GL_VIEWPORT);
    
    glSelectBuffer_c($BUFSIZE, $selectBuf);
    glRenderMode(GL_SELECT);

    glInitNames();
    glPushName(-1);

    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
        glLoadIdentity();
    #/* create 5x5 pixel picking region near cursor location */
        gluPickMatrix_p($x, ($viewport[3] - $y), 5.0, 5.0, @viewport);
        gluOrtho2D(0.0, 3.0, 0.0, 3.0);
        draw("GL_SELECT");
    glPopMatrix();
    glFlush();

    $hits = glRenderMode(GL_RENDER);
    processHits ($hits, @selectBuf);
    
#    glutPostRedisplay();
} 

sub processHits {
my ($hits, @buffer)=@_;
    my $i, $j;
    printf ("hits = %d\n", $hits);
    for ($i = 0; $i < $hits; $i++) {    #/* for each hit */
        printf (" number of names for this hit = %d\n", $buffer[$i]);
    printf ("\n");
    }
}

# The main drawing function.
sub draw_scene
{
    my $widget = shift;
    my $glcontext = $widget->get_gl_context;
    my $gldrawable = $widget->get_gl_drawable;

    # OpenGL BEGIN
    return unless( $gldrawable->gl_begin ($glcontext) );

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glTranslated(0, 0, -100);
    glRotated($room_rot, 0, 1, 0);
    glCallList($graphic);
    $room_rot += 0.5;

    if( $gldrawable->is_double_buffered )    {$gldrawable->swap_buffer
+s;}
    else {glFlush();}
    $gldrawable->gl_end;

    1;
}


sub draw {
my $mode=shift;
$graphic = glGenLists(1);
glNewList($graphic, GL_COMPILE);
    if ($mode eq "GL_SELECT") {glLoadName(1);}
    glTranslated(0, 0, 10);
    Gtk2::Gdk::GLExt::Shapes->draw_sphere (1, 3, 10,10);
glEndList();

#glPopName();
}

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In reply to Re^4: Perl and OpenGL object selection by szgezu
in thread Perl and OpenGL object selection by szgezu

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