pset4 Ball is not moving

Question

Issue: the ball is not moving.

Code:

// keep playing until game over
while (lives > 0 && bricks > 0)
{
    while (true)
    {
        // check for mouse event
        GEvent event = getNextEvent(MOUSE_EVENT);

        // if we heard one
        if (event != NULL)
        {
            // if the event was movement
            if (getEventType(event) == MOUSE_MOVED)
            {
                //move paddle
            }
        }
    }

    // BALL
    // initial velocity
    double velocity = 2.0;

    // bounce forever
    while (true)
    {
        // check for mouse event
        GEvent event = getNextEvent(MOUSE_EVENT);

        // if we heard one
        if (event != NULL)
        {
            // if the event was movement
            if (getEventType(event) == MOUSE_CLICKED)
            {

                // move circle along x-axis
                move(ball, velocity, 0);

                // linger before moving again
                pause(10);
            }
        }
    }

But, for some reason the ball is not moving. I have tried to put paddle and ball inside the same while (true) loop, but I get segmentation fault back.

Answer 1

The ball is never moving because you're having an infinite loop at the beginning of the outer while loop

while (lives > 0 && bricks > 0)
{
    while (true)
    {
        // do something
    }

    // CONTROL NEVER REACHES THIS LINE BECAUSE IT NEVER LEAVES THE PREVIOUS LOOP
}

After you fix this, you'll probably have another similar issue with the infinite loop at the end of the outer while loop. You probably don't need any loops inside of the outer loop.

Also, you need not to listen to a MOUSE_CLICKED in every iteration of the outer loop. This loop is basically responsible for the whole game. It's responsible for listening to MOUSE_MOVED events to move the paddle, for moving the paddle, for moving the ball, for bouncing the ball off, for detecting collisions, removing bricks, updating the score/lives and so on.

Although you might take some of these things out and place them in their own functions, you'll probably still call these functions from inside this loop.

Imagine that you're waiting for a click every time you wanna move the ball! That'd be a little boring, wouldn't it?

Answer 2

You don't want the ball to move forever, only when lives>0 and bricks>0. If one of those two conditions are false, your ball should stop moving. Hence, no need to have the forever loop. You want the ball to move in the x-axis AND y-axis, so set a velocity in the x-direction and the in the y-direction. Use the bounce file as a preliminary step to get an understanding of the source code.

Answer 3

Are you sure the ball isn't moving? What happens if you lose 3 lives, do you call removeGwindow? If not, the ball may in fact have moved already, and you've lost 3 lives so your ball is frozen (unless you did call removeGwindow). Just for debugging purposes, try reducing velocity to something like .005 so you can see if it does move.