Running a for and while loop simultaneously

Hi all,

I need to make one graphical experiment using Psychtoolbox.

The goal is to create some kind of game in which (a) "apples" (green ovals) will fall down from the top of the computer screen (starting at random positions). As if it would be "raining" ovals. I have the script ready for this. Also, (b) a bar will be present on the screen which a participant can move using the keyboard (key L for moving the bar to the right and key A for moving the bar to the left). I have the script ready for this.

The goal is that participants can "catch" the apples with the bars. This means that both my scripts need to be combined into one. I want participants to be able to move the bar while the apples are falling, but that the speed of the bar and the speed of the apples are independent of each other. Both scripts are working, but I have no idea how to combine them together so that the game will work as I want. For now I have tried different structures, but it will results in events like ' one apple falls > a bar can be moved (after the apple has dissappeared) > when i hit Escape another apple falls, etc.. Obviously, this is wrong. See below the (overview and structure of) two seperate working scripts.

SCRIPT A: FALLING APPLES

for a = 1: nApples

    set a randomposition for each apple to start from

       for i = 1:100

Use Screen function to draw an oval on the screen, which position will be updated (= a bit lower) on each loop. Every apple has 100 positions before it hits the bottom of the screen and dissapears.

      end

end

SCRIPT B: MOVING THE BAR

while KbCheck end

while 1 [KeyIsDown, seconds, keyCode] = kbCheck;

if KeyIsDown

Record the KeyCode and update the horizontal position of the bar

end

while KbCheck; end

Draw the bar on the screen using the Screen function.

end

end

Is there anyone who could help me get on the right track?

Thanks, Amber