Creating a Level Editor - Scratch 2.0 Game Development - page 208

We can then add the basic movement controls. As we have to keep in mind that the cat
shouldn't be allowed to walk through walls, we have to perform a check before each move.
This check will be the same for each step we take.

We will create another funcion to deine this repeated collision check. Regardless of the key
pressed or the direcion the cat will move in, the check will stay the same.

To set up the keyboard controls, we create four-key pressed script, as we have done in earlier
examples. For each direcional key, we point the cat in the right direcion as follows:

When the cat is facing the correct direcion, we can make it try to take a step forward. We
create a funcion to describe this move atempt. If the way is clear, the cat will move. If it's
blocked by a wall, the cat will stay where it is. Perform the following steps:

1. Click on the More Blocks category.
2. Then, click on the Make a Block buton.
3. Name the new funcion as takeStep and click on OK without selecing opions.

Another staring block will appear called define takeStep . This is the start of the script where
we can write all the steps the funcion should take. Perform the following steps:

1. To the define takeStep block, add set the replace item <1> of <xySave> with x
posiion block (the built-in variable).
2. Then, add the same for the y posiion; by seing the replace item <2> of <xySave>
with y posiion block (the built-in variable).
3. Then make the cat move twenty steps by seing the move (20) steps block. This
corresponds to one ile segment, as we calculated earlier when planning the maze
iles.

4. Add an if () else () statement to check for collision and decide what acion to take

depending on the result.