Lab 5: Animation

Download and unzip lab5.zip, which contains all the files you will need for this assignment. Open the file Lab5.java in DrJava. All the code you write for this assignment should be added to this file.

Be sure to test your code after completing each step.

  1. Insert code to make a new drawing window appear. Draw a small ball (or other entity) in the bottom left corner of the window.
  2. Modify your program so that it shows the ball move to the right, from the bottom left to the bottom right corner of the window. Use a variable to store the x-coordinate of the ball. Use a loop to repeatedly draw the ball at that x-coordinate, pause for a short amount of time, and increase the x-coordinate by some amount. Feel free to fine tune these values until the animation feels right.
  3. Modify your program so that the ball moves diagonally up and to the right, by decreasing the ball's y-coordinate as you increase the ball's x-coordinate.
  4. At the beginning of the program, prompt the user to enter the x-velocity and then the y-velocity. Remember these values. Modify your loop so that, whenever you adjust the x-coordinate of the ball, you increase it by the x-velocity the user entered (instead of using the amount you chose earlier). Likewise, increase the y-coordinate by the y-velocity entered.
  5. In the real world, what goes up must come down. Modify your program so that the ball is gradually pulled down by gravity. This is easier than it sounds. Inside the loop, add a fixed amount to the y-velocity. (Do you see why this will work?) The ball should now follow a parabolic path. Feel free to fine tune your values until it looks right.
  6. Draw a target somewhere on the right side of the window.
  7. If the ball passes near the target, display a message. Something like "You win!" or "You hit the target! Now you'll have to pay for a new one!"
  8. Modify your program so that it places the target at a random height.
  9. Some Challenging Suggestions:Modify your program so that the user can keep shooting at the target until you hit it. Then change the height of the target and let the user continue shooting that one. Keep track of the number of times the user hits the target. Modify the program so that the user enters the angle and velocity of their shot, instead of entering the x-velocity and y-velocity.