=head1 TITLE

anim_image_dblbuf.pir - animate an image in a doublebuffered Parrot SDL window

=head1 SYNOPSIS

To run this file, run the following command from the Parrot root directory:

    $ ./parrot examples/sdl/anim_image_dblbuf.pir
    Drew 540 frames in 2.200484 seconds (245.400580 fps)
    $

=cut

.sub _main :main
    load_bytecode "SDL/App.pir"
    load_bytecode "SDL/Color.pir"
    load_bytecode "SDL/Rect.pir"
    load_bytecode "SDL/Image.pir"
    load_bytecode "SDL/Sprite.pir"

    .local pmc app
    app = new ['SDL'; 'App']
    app.'init'( 'height' => 480, 'width' => 640, 'bpp' => 0, 'flags' => 1073741825 )

    .local pmc main_screen
    main_screen = app.'surface'()

    .local pmc dest_rect
    dest_rect = new ['SDL'; 'Rect']
    dest_rect.'init'( 'height' => 100, 'width' => 100, 'x' => 0, 'y' => 190 )

    .local pmc prev_rect
    prev_rect = new ['SDL'; 'Rect']
    prev_rect.'init'( 'height' => 100, 'width' => 101, 'x' => 0, 'y' => 190 )

    .local pmc source_rect
    source_rect = new ['SDL'; 'Rect']
    source_rect.'init'( 'height' => 56, 'width' => 100, 'x' => 0, 'y' => 0 )

    .local pmc black
    black = new ['SDL'; 'Color']
    black.'init'( 'r' => 0, 'g' => 0, 'b' => 0 )

    .local pmc image
    image    = new ['SDL'; 'Image']
    image.'init'( 'examples/sdl/parrot_small.png' )

    .local pmc sprite
    sprite = new ['SDL'; 'Sprite']
    sprite.'init'( 'surface' => image, 'source_x' => 0, 'source_y' => 0, 'dest_x' => 0, 'dest_y' => 190, 'bgcolor' => black )

    .local num start_time
    time start_time

    _animate_on_x_axis( main_screen, sprite,   0, 540,  2)
    sleep 1
    _animate_on_x_axis( main_screen, sprite, 540,   0, -2)

    .local num end_time
    time end_time

    .local num total_time
    total_time = end_time - start_time
    dec total_time

    .local num fps
    fps = 540 / total_time

    print "Drew 540 frames in "
    print total_time
    print " seconds ("
    print fps
    print " fps)\n"

    sleep 1

    app.'quit'()
    end
.end

.sub _animate_on_x_axis
    .param pmc screen
    .param pmc sprite
    .param int start_pos
    .param int end_pos
    .param int step_size
    # PMCs:
    #    destination SDL::Surface and SDL::Sprite to animate
    # Ints:
    #    starting and x coordinates and number of pixels to move at a time

    .local int x_pos
    x_pos = start_pos

_loop:
    add x_pos, step_size
    sprite.'x'( x_pos )
    sprite.'draw'( screen )
    screen.'flip'()
    if x_pos != end_pos goto _loop
.end

=head1 AUTHOR

chromatic, E<lt>chromatic at wgz dot orgE<gt>.

=head1 COPYRIGHT

Copyright (C) 2004-2008, Parrot Foundation.

=cut

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