sub image_draw {
        my ( $image,$x,$y,$xsize,$ysize ) = @_;
        glBindTexture(GL_TEXTURE_2D, $image);

        $xmax = $x + $xsize;
        $ymax = $y + $ysize;



        glBegin(GL_QUADS);                                          
        glTexCoord(0.0, 0.0);glVertex($x, $y,  0);
        glTexCoord(1, 0.0); glVertex( $xmax, $y,  0);
        glTexCoord(1, 1); glVertex( $xmax,  $ymax,  0);
        glTexCoord(0.0, 1);glVertex($x,  $ymax,  0);

        glEnd();                                             


}

sub InitGL {
        my ($Width, $Height, $kernel, $heap)=@_;

        glViewport(0, 0, $Width, $Height);
        #LoadGLTextures();  
        image_load("./Media/imgs/",$kernel,$heap);

        glEnable(GL_TEXTURE_2D());                  

        glClearColor(0.0, 0.0, 0.0, 0.0);                            
        
        glClearDepth(1.0);                                           
        glDepthFunc(GL_LESS());                                    
        glEnable(GL_BLEND);
                                         
        glDisable(GL_DEPTH_TEST);
        glShadeModel(GL_SMOOTH());                                   

        glMatrixMode(GL_PROJECTION());
        glLoadIdentity();                                           
        #glOrtho(0,640,0,480);
        gluOrtho2D(0, $Width, $Height,0);
        gluPerspective(45.0, $Width/$Height, 0.1, 100.0);           

        glMatrixMode(GL_MODELVIEW());


        glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
        glColor(1.0, 1.0, 1.0, 1.0);
        glTranslate(0.0,0.0,-2.0);                                 


}

# that part load the textures.
-------
                  my $textures = glGenTextures(1);                #name texture
                                     die "Could not genereate textures" unless $$textures[0];

                                debug_print("loaded at slot $index",$kernel,$heap);
                                glBindTexture(GL_TEXTURE_2D, $$textures[0]);   # 2d texture


                                glTexParameter(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); # scale linearly when image bigger than texture
                                glTexParameter(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); # scale linearly when image smalled than texture

                                glTexImage2D(GL_TEXTURE_2D(),
                                           0,                      
                                           GL_RGBA(),                      
                                           $width,$height,
                                           0,                      
                                           GL_RGBA(),                
                                          GL_UNSIGNED_BYTE(),       
                                          $pixels);            

#-------------------------------------------------------------
image_draw($heap->{"images"}->{"2_bgtile"},0,0,640,480);