Question

I know the following code will move an object in a straight line. How can I get the object to travel in a wavy line? I know that something extra is required for the x variable.

public void draw(Graphics2D g) 
        {
            g.setColor(Color.WHITE);
            g.fillOval ((int) (x - r), (int) (y - r), (int)
                    (2 * r),
                    (int) (2 * r));

            y++;


            if (y - r > height)
                y = -r;
        }

Answer 1

Use the sine or cosine function to calculate y as a function of x.

Multiply the sine or cosine function to increase the amplitude (how high it goes)

y = 100 * sin(x) // will make it have peaks of -100 and 100

Divide the x to increase the period. (distance between peaks)

y = sin(x/2) // will make it take twice the x distance between peaks.

Something like this:

public void draw(Graphics2D g) 
    {
        g.setColor(Color.WHITE);
        g.fillOval ((int) (x - r), (int) (y - r), (int)
                (2 * r),
                (int) (2 * r));

        x++; // Left to right movement
        // Example, modify the multipliers as necessary
        y = 100 * Math.sin(Math.toDegrees(x/4))
    }