Moving the Bird
A. Setting up the City
Steps: 1. Click on the "graphics" sub stack, import the picture of the city and note it's ID # 2. Drag over a button to the main stack, name it "city01" and set its icon to that of the city
We are going to move that button (city01) to the left and it will look like the bird is moving and when it goes off the left of the screen (card), bring it back on the right side of the screen (card)
We need a second copy of the city to fill the gap on the page as the first one goes off the screen Add a button and call it "city02". Set it's icon to the (same) number of the city graphic as above
Don't forget to go to the "Size and Position" of the property Inspector and click on "Fit to Content" and move the layer to the back so the buttons show in front of the city
Now add the following code to the card script (in the "moveBird" message handler): Every time we move the bird, we will also move the city It will move each button to the left by 3. When each city goes off the screen, it will be added to the other city on its right. The cities will look like they are moving together with no break between them
set the bottom of btn "bird" to the bottom of btn "bird" + birdDirection * birdSpeed set the right of btn "city01" to the right of btn "city01" - 3
set the right of btn "city02" to the right of btn "city02" - 3
if the right of btn "city01" < 0 then
set the left of btn "city01" to the right of btn "city02" -3
if the right of btn "city02" < 0 then
set the left of btn "city02" to the right of btn "city02" -3
send "moveBird" to me in 20 millisecs
Now click on the card - Property Inspector and set the background sky to a nice blue color
C. The entire code that goes on the card is below: Card Script: (this code goes on the card)global birdDirection // +1 is down, -1 is up
global birdSpeed // speed the bird falls
global gameisRunning
on moveBird
set the bottom of btn "bird" to the bottom of btn "bird" + birdDirection * birdSpeed
set the right of btn "city01" to the right of btn "city01" - 3
set the right of btn "city02" to the right of btn "city02" - 3
if the right of btn "city01" < 0 then
set the left of btn "city01" to the right of btn "city02" -3
if the right of btn "city02" < 0 then
set the left of btn "city02" to the right of btn "city02" -3
if gameisRunning then
send "moveBird" to me in 20 millisecs
end if
end moveBird
on startGame
put true into gameisRunning
put +1 into birdDirection // bird will be falling
put 3 into birdSpeed
moveBird
end startGame
on stopGame
put false into gameisRunning
set the bottom of btn "bird" to 400
end stopGame
on keyDown theKey
if theKey is space then
put -1 into birdDirection // move the bird up
end if
end keyDown
on keyUp
put +1 into birdDirection // let the bird start falling again
end keyUp
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