Paddle Bounce IV

Review — where we got to 5 min

The wall exists and can be cleared. When it is, nothing happens — that is today.

• A repeat (6) lays the row out; each clone waits to be hit and deletes itself.
• Every break speeds the ball up and shrinks the paddle.

Quick-fire

How does the game know the last target has gone?

Today’s Topic 3 min

• A variable that counts what is left, because clones cannot be counted
• A builder that takes orders, so one loop can make every level
• Two endings: winning and losing, and why they must look different
• A title screen and a best score, the same shape as Jump Dash’s

Learning outcome

By the end of this lesson you will be able to:

1. Notice the moment a wall is cleared.
2. Build a harder wall from the same loop.
3. Give a game a win screen that is not its game-over screen.

Learnt — counting, levels, and winning 27 min

1 · Counting what is left

A deleted clone leaves nothing behind. So the row keeps its own tally, and the last break is the one that reaches zero.

1. Make a variable called targets.
2. In the builder, before the repeat, set [targets v] to (0).
3. Inside the repeat, after the clone, change [targets v] by (1).
4. In the clone stack, before the delete, change [targets v] by (-1).
5. Then ask if <(targets) = (0)> then and broadcast cleared.
6. Play, clear the row, and watch the number fall to zero.

when I start as a clone
show
wait until <touching [Ball v]?>
start sound [Glass Breaking v]
change [score v] by (10)
change [targets v] by (-1)
if <(targets) = (0)> then
  broadcast [cleared v]
end
delete this clone
            

2 · The next level

The builder becomes something you can ask for a wall. Level 1 asks for one row; level 2 asks for two.

1. Make a variable called level and set it to 1 on the flag.
2. Change the builder’s hat block to when I receive [build v].
3. On the flag, broadcast [build v] once.
4. Wrap the row-building repeat in another repeat (level), stepping down 60 each time round.
5. On when I receive [cleared v]: change [level v] by (1), wait, then broadcast build again.
6. Play until level 2 appears.

when I receive [build v]
hide
set [targets v] to (0)
go to x: (-175) y: (130)
repeat (level)
  repeat (6)
    create clone of [myself v]
    change [targets v] by (1)
    change x by (70)
  end
  set x to (-175)
  change y by (-60)
end
            

3 · Two endings

The game can now be won. A win that looks like a loss is worse than no win at all, so they get different screens.

1. In the cleared stack, ask if <(level) = (3)> then before building again.
2. If it is, broadcast [you win v] instead.
3. On the paddle, receive it: a different backdrop, a cheer, and the score.
4. Check the game-over screen still says something different.
5. Win it once and lose it once.

when I receive [you win v]
switch backdrop to [Light v]
start sound [Cheer v]
say (join [All three levels! Score: ] (score)) for (4) seconds
stop [all v]
            

Basic — build three levels 25 min

The count comes first. Nothing else works without it.

Step 1 — counting

1. Make the targets variable and count up as you build.
2. Count down in the clone stack.
3. Clear a row and check it lands exactly on zero.

Step 2 — the message

1. Broadcast cleared at zero.
2. Receive it somewhere and say something, just to prove it arrives.

Step 3 — the builder takes orders

1. Move the builder onto a receive hat.
2. Broadcast build from the flag.
3. Check level 1 still looks exactly as it did.

Step 4 — more levels

1. Add the outer repeat and the row step.
2. Raise the level on cleared and build again.
3. Play up to level 3.

Step 5 — the two endings

1. Win on level 3 instead of building a fourth.
2. Make the win screen look nothing like the game-over one.
3. Reach both endings before you leave.

Three levels that feel different

More targets is not a new level, it is the same level twice. Give each of yours one idea.

• Three levels, each with something the others do not have.
• You can say in one sentence what each level is about.
• All three are winnable.

Give it a front door

You built one of these in Topic 1.39. Build the same thing here, from memory, for this game.

• A title screen with the game’s name and one button.
• Nothing runs until the button is clicked.
• A best score that survives losing.
• A way to play again without the green flag.

Every ending accounted for

Write down every way your game can stop. Then check each one has a screen a player would understand.

• A list of every way the game can end.
• Each one tested, on purpose.
• None of them leave the player looking at a frozen Stage.

A second player at the top

Put a paddle along the top, give it two keys of its own, and let the ball be lost at either end.

• Two paddles, two sets of keys, both reachable at one keyboard.
• A ceiling that loses the ball, the same way the floor does.
• A point to whoever did not miss.
• Both paddles move at the same speed, and both are the same size.

Summary 4 min

Paddle Bounce is finished, and it is the first game in the course you can win.

1. Clones cannot be counted, so a variable counts them.
2. A builder on a receive hat can be asked for a bigger wall.
3. A loop inside a loop builds rows instead of a row.
4. Winning and losing need different screens, or neither means anything.

Level

A number the builder reads. Change it and the wall changes.

targets

How many are left. Counted up as they are built, down as they break.

Cleared

The broadcast that goes out when the last target breaks.

Win screen

An ending that looks nothing like the losing one.

Next lesson: the last arc of Level 1 — one project with all of your games inside it.