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Transcript

In this video, you'll program the receiver sprites to move around, then stop once it catches the ball sprite.

Click on the receiver sprite.

Start by making the receiver spot move around the whole stage.

From the motion menu, drag out a move block.

To make the receiver sprite keep moving for the entire game, put that block inside a forever loop.

Go ahead and click on the code.

The receiver keeps moving, but quickly runs off the stage.

To keep that from happening, go to the motion menu, find the if on edge bounce block, and place it inside the forever loop.

Click the stack again.

Much better.

Right now, the receiver sprite just moves left and right.

To make the receiver sprite choose a direction in which to move, go to the motion menu and find the point in direction block.

Add it to the top of the block stack.

To make it choose a random direction, go to the operators menu, find the pick random block, and place it in the value blank of the point in direction block.

The numbers you enter in this block will determine the receiver's direction.

To make it go in any possible direction, put zero and 360 in the pick random block.

Click the code and watch where the sprite moves.

Click the stop sign.

Then click the code again and watch it move in a new direction.

The receiver can start moving in any direction now.

That's pretty awesome.

The receiver needs to catch the ball.

To do that, it needs to sense if it is touching the ball sprite and react as soon as it is.

From the control menu, drag out an if block and place it inside the forever loop.

From the sensing menu, place a touching block inside the if.

Click the drop down and select ball sprite.

The code will keep checking over and over if the receiver is touching the ball sprite.

Next, tell the receiver what to do when it catches the ball.

It will change costumes to the one that has received the ball.

From the looks menu, place a switch costume to block inside the if block.

From the drop down, select the received costume.

It doesn't need to keep running around once it has caught the ball, so make it wait a short bit, then get out of the way.

To make it wait, from the control menu, place a wait block under the switch costume to block.

To make it disappear, from the looks menu, place the hide block under the wait block.

Tinker with the weight block's value until the sprites disappear at a time that makes sense to you.

If the receiver hides, it also needs to show.

Place a show block at the top of the block stack so that the receiver is always visible when it's running around, then it hides when it gets the ball or the puck.

Finally, make this code start when the flag is clicked by placing a when flag click block on top of the code stack.

Test the code by clicking the flag.

The receiver sprite should point in a random direction, move, and bounce when it touches the edge of the screen.

Aim the ball sprite with the arrows and press the space bar when you're ready to pass to the receiver.

If the ball sprite hits the receiver sprite, the receiver sprite should stop moving.

Keep trying until you see the code work.

Wait a second.

The receiver sprite never returns to its first costume after it changes.

To make this happen, from the looks menu, place a switch costume to block just under the when flag click block.

Select the moving costume.

Click the flag again.

The sprite starts by looking like its running, then looks like it catches the ball sprite.

All right, here's the game plan.

Program the receiver sprite to run around the stage using the move, if on edge bounce, and forever blocks.

Program the receiver to change costume if it catches the ball using wait, show, hide, and switch costume to blocks.

Make it start moving in a random direction using the point in direction and pick random blocks.

Finally, program the receiver to change costumes and stop when it catches the ball using the block shell.

Instructions
  1. Program the receiver sprite to run around the stage using the "move," "if on edge bounce," and "forever" blocks.
  2. Program the receiver sprite to start moving in a random direction using the "point in direction" and "pick random" blocks.
  3. Program the receiver sprite to change costumes and stop when it catches the ball using the "if" "touching" "switch costume to" and "stop this script" blocks.