Setting Things Up
Because you’re learning how to code in Scratch and not how to build a physics engine (code that makes things in a computer game behave like real-world objects, e.g. they don’t fall through floors), you’ll be starting with a project I’ve created that already has the basics for moving, jumping, and detecting platforms built in.
You should take a quick look at the project, including the details on this card, because you’ll be making some changes to it later, but you don’t need to understand everything it’s doing!
Get the project
The first thing you’ll need to do is to get a copy of the Scratch code from here.
To use the project offline, download it by clicking See Inside, then go to the File menu and click Download to your computer. Then you can open the downloaded file in Scratch on your computer.
You can also use it directly in Scratch in your browser by just clicking See Inside and then Remix.
Take a look at the code
The physics engine of the game has a variety of pieces in it, some of which work already and some of which don’t yet. You can test this out by running the game and trying to play it.
You’ll see that you can lose lives, but nothing happens when you run out. Also, the game only has one level, one type of thing to collect, and no enemies. You’re going to fix all of that, and a then do a bit more!
Take a look at how the code is put together.
It uses lots of My blocks blocks, which are great for splitting your code up into pieces so you can manage it better. A My blocks block is a block you make up out of a lot of other blocks, and you can give some instructions to it. You’ll see how it works in an upcoming step!
‘My blocks’ blocks are really useful
In the code above, the main game forever loop calls the main-physics My blocks block to do a whole lot of stuff! Keeping the blocks separated like this makes it easy to read the main loop and understand what happens in the game, without worrying about how it happens.
Now look at the reset game and reset character My blocks blocks.
They do pretty normal things, such as setting up variables and making sure the character rotates properly
reset-gamecallsreset-character, showing you that you can use a My blocks block inside another My blocks block- The
reset-characterMy blocks block gets used in two different places in the main loop. This means you can change two places in your main game loop by only changing the code inside of the My blocks block, which saves you a lot of work and helps you avoid mistakes.