MATLAB: Concurrent interaction using functions

ballfunctionswindow

I'm coding a program that allows objects to bounce within a window. I have successfully gotten one ball to bounce within it. But when I try to add a second ball, only the first ball moves.
This is the function that allows the object to rebound a wall and it does this indefinitely (While loop) I'm pretty sure the second objcet doesnt show up because the first function is running forever while the while loop is being run (no pun intended). So how do i get the second object to appear and to move concurrently with the first object?
function bounce = bounceFunc(obj, addx,addy,x,y)
    
    %CREATE A FUNCTION OF THIS SO THAT YOU CAN REUSE IT FOR MULTIPLE BALLS
    while (x >=0 & x <= 500) & (y >= 0 & y <= 500) 
        %while the ball is within the window. (extra tolerances???)
        %retrieves position for following if statements to determine direction
        [x y] = getCenter(obj)
        if y >= 480
            addy = -addy
        end
        if y <= 20
            addy = -addy
        end
        if x >= 480
            addx = -addx
        end
        if x <= 20
            addx = -addx
        end
    xMove(obj,addx) 
    yMove(obj,addy) 
    redraw
    end
    
end

Best Answer

You have to modify the code of bounceFunc to accept arrays for all inputs:
function bounce = bounceFunc(obj, addx,addy,x,y)
    n = numel(obj);  % Number of objects
    
    %CREATE A FUNCTION OF THIS SO THAT YOU CAN REUSE IT FOR MULTIPLE BALLS
    while all((x >=0 & x <= 500) & (y >= 0 & y <= 500))
        for k = 1:n
          [x y] = getCenter(obj(k));  % You overwrite the inputs x and y here?!
          if y >= 480
              addy(k) = -addy(k)
          end
          if y <= 20
              addy(k) = -addy(k)
          end
          if x >= 480
              addx(k) = -addx(k)
          end
          if x <= 20
              addx(k) = -addx(k)
          end
          xMove(obj(k),addx(k)) 
          yMove(obj(k),addy(k)) 
        end
    redraw
    end
end
Now create the balls before calling the bounceFunc equivalently:
obj(1)       = drawBall(xc, yc, rad, col)
[x(1), y(1)] = getCenter(obj(1))
...
obj(2)       = drawBall(xc, yc, rad, col)
[x(2), y(2)] = getCenter(obj(2))
etc.
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