% The Moving Bird

var logoPicID, bgPicID : int
% Picture ID's and background
var logoWidth, logoHeight : int
% Width and Height
var x, y : int := 0
% Lower left corner of bird
var dx, dy : int := 3

% Load the logo from file and get its height and width
logoPicID := Pic.FileNew ("airplane2.bmp")
logoWidth := Pic.Width (logoPicID)
logoHeight := Pic.Height (logoPicID)

%Load the background from the file and draw it in the dinow
Pic.ScreenLoad ("mountain_background.bmp", 0, 0, picCopy)

loop
    % Take the picture of the background
    bgPicID := Pic.New (x, y, x + logoWidth, y + logoHeight)
    % Draw the bird
    Pic.Draw (logoPicID, x, y, picMerge)
    delay(50)
    % Draw the background over the bird
    Pic.Draw (bgPicID, x, y, picCopy)
    % Free up the memory used by the background picture
    Pic.Free (bgPicID)
    %Check if the logo bounced of the left or right edges of the window
    if x + dx < 0 or x + dx + logoWidth > maxx then
        dx := -dx
    end if
    %Check if the logo bounced off the top or bottom edges
    if y + dy < 0 or y + dy + logoHeight > maxy then
        dy := -dy
    end if
    % Change the location of the Bird
    x := x + dx
    y := y + dy
end loop