Hello World!

I'm going to create a movie with

a dancing bird.

in Alice 3.

I've set up a scene with the

Southwest and a Phoenix.

I've created 2 scene procedures,

Jump and spin.

For the bird to dance, and I might call

*one twice, I mght do them in a different order.

Usually, when you're doing animation,

We do one thing and then put them back where they started.

Variables make it really easy to do this.

And let's just add another.

scene procedure,

just as a review.

Som scene procedure,

Call this backflip.

Add a comment.

//Bird does backflip

OK.

Let's go to myFirstMethod.

I can now

drag in

backflip

wherever I want it.

Right now I don't have any code in any of those procedures,

Except a coment let's go to jump.

One way to go to jump would be to

Click on it here.

Another way would be to click edit here.

And another way.

Right-click.

Select that

folder looking thing.

Go to jump.

So all of the movement

in Alice is double,

is the type for that and I want him to jump up in the air, but I'm not really sure at this point how high I want him to jump but whatever that is,

he will come back down the same amount.

to end up where he started.

Let's add a variable.

And this is going to be a double.

Call theis jumpAmount

Did you notice I can use a capital letter here ["A"]

That's called camel case, that just makes it a little bit easier to read.

Let's start with an amount of 1.

And then I'm going to have the Phoenix.

move up

that jumpAmount,

and then

Let's have him move down

again,

jumpAmount

Let's run it. When we run it,

myFirstMethod calls spin- there's no crowd there- it  calls backflip - there's no code there- and it calls jump. So right now all we're going to do is see him jump.

But if I had code there,

I could disable those two and focus on just the jump that I want to do.

I want him o jump higher than that.

So let's go back here to jump,

Change this to 2.0.

So let's just add a little something here.

Let's have the Phoenix.

spread his wings.

and then fold his wings.

down

Let's add...

A doTogether block here.

Have himsSpread his wings,

and move up at the same time.

Another doTogether block

And have him

fold wings and down

That's kind of what I wanted.

And I can go on.

You can see we could experiment with that amount to jump.

And really use variables very nicely because,

if I didn't have a variable I would have to change this in two places.

So top-down design.

I could Have him jump twice.

Turn around and do all these fun things.

Add another jump, he jumps twice.

All right!

And that's it.