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In this video we'll add code to the ship

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to control it with the keyboard.

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That way we'll learn about
Godot's input mapping features

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and how to listen to input in our code.

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Head to the project menu in the top left,

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then Project Settings
and to the Input Map tab.

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This tab lists the key mappings
in your Godot project.

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It allows you
to map keys on the keyboard

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mouse clicks, mouse buttons

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or buttons on a gamepad

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to a name you can use conveniently.

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Now you have a bunch
of them that come precreated

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in every Godot project
for user interfaces.

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We also created a couple more
in this project for the practices

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and for a couple of features
we have in this course.

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But we're going to be recreating
a couple for practice in there.

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I invite you to scroll
to the point you see the move_left input

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and on the right we're going
to be clicking this dust bin

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to remove the move left input.

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So click the input next to that
to move right, move up, down and boost

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because we'll be remaking them.

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I'll scroll back to the top

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and typically the way
you would create a new input mapping

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is by going to this action bar
and you start by typing in the name.

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For example, to move left we'll use
something like Move and Scroll Left.

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You can press Enter to add
the input action and it will be appended

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at the bottom of the list.

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Then, to the right you have
a little "add event" button.

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If you click it you get a drop down menu

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where you can choose
the kind of key or button

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that you want to map to this action.

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Typically you'll want
to use something like

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Physical Key or Key for the keyboard.

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Joy Button and Access are for gamepads

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and Mouse Button
for the mouse or touchscreens.

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The difference between
Physical Key and Key

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is that people have different
keyboard layouts around the world.

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For example, in North America they use
the WASD keys to move a character.

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In France, we might use ZQSD
because the layout is different.

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Physical Key is going to store
the position of the key on the keyboard

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rather than the letter.

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and that's what we'll be using in here.

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Click Physical Key and then
you can type A, for example,

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to make the character move left.

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Now we're going to create
three more inputs like these

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for the move_right,
up, and down actions.

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In the action bar type
"move_right".

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We're going to create them all at once.

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So move_up
and move_down.

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For move_right, you click
the plus button next to it.

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Physical Key, press the D key in my case

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click OK, move up, same thing.
Physical Key.

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I'm going to press W, click OK to
create the action and then Move Down.

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I'm going to add Physical Key.

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Press S to move down and OK,

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and with that we have the input actions
and we can start using them in our code.

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Can click the Close button
to get back to the script editor.

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We will now add
a couple of lines of code

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to calculate the desired
move direction of the player

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based on the key presses.

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I invite you to put your cursor
at the end of the process function

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and press Enter
to insert a couple of lines

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because we need to add code
at the top of the function.

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We'll start by defining
a variable named "direction"

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that will be our ship's move direction

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and we will initialize it
with a value of Vector2.ZERO.

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Now, typically a direction vector is
a vector with a maximum length of one.

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This allows us to represent
only the move direction of the player

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and we can multiply that by a speed

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to give our ship a velocity.

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That is to say,
a direction and a speed together.

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Let's calculate the direction
and I'll explain as we go.

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So we're going to start
with the horizontal direction.

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On a new line we type,
direction.x =

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and we're going to type,
Input.get_axis

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and then this is a function
that is going to give us a value

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between minus one and one depending

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on the two input actions
that we give it as arguments.

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We first have to write the input

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that makes the value
go towards minus one.

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This is going to be move_left
because minus one represents

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the left horizontal
direction in the engine

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and then we add a comma
followed by move_right.

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Note how you have to put
the input actions defined

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in the project settings in quotes there.

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This is going to give us minus one
if we press the A key

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and one
if we press the D key.

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Then we're going to do
something similar for the y-axis.

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direction.y =
and you can copy the Input.get_axis call

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from the line above
and press Control V to paste it there.

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We just have to change the input action.

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So we're going to turn
move_left into move_up

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because minus one
on the vertical axis represents moving up.

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We're going to change
the second argument to, move_down.

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Before we move on,
a word on this input thing here.

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It's what we call a "global object".

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It's something
you can access in any script

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and you can call functions on it,

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functions that are useful
to make your game.

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You can use it to calculate
the mouse position,

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to know if a key was pressed.

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We'll see that moving
forward in the course.

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Now we're going
to change how we move the ship.

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We want to calculate our velocity

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by multiplying the direction vector,
we just got, by some speed value.

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At the top of our script,

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we're going to define
a new variable named "max speed".

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This will be the ship's
maximum movement speed

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and let's set it
to 600 pixels per second.

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Then we can change
the default value of the velocity

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because now the velocity
will depend on our keyboard input.

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We'll set it to Vector2.ZERO.

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That is to say, if we don't press anything

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at the start of the game,
the ship will not move.

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Down before we change the position,
we're going to calculate the velocity.

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Like so: we're going to write
velocity is equal to direction

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multiplied by maximum speed.

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This is a fairly typical way
of coding movement in games.

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You will see why
at the end of the series

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when we add smooth
movement to the ship.

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You can try your game
by pressing F6 on your keyboard.

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Now, if you press WASD,
you will see your ship can move.

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It moves horizontally, diagonally

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and the thrusters
update when it's not moving.

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There's one thing we need to fix though.

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If you try to move horizontally and then
diagonally, you should see that

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when you go diagonally,
the ship moves instantly faster.

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Why is that?

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Well, this is due to our
direction calculation right now.

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When we only go
horizontally or vertically,

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we might get a value
of one on that axis.

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But when we go diagonally,
we get an x direction, say, of one

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and a y direction of one,

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and our vector ends up being longer.

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So it's increasing our velocity.

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But we want the ship
to move at the same speed

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regardless of its move direction.

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To do that, we have to
add some condition, like so.

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After calculating the direction,
we're going to add new lines.

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We're going to say, "if direction.length",

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length is a function that tells you
the length of the vector.

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If it's greater than one,
so if we're moving diagonally, basically,

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we're going to change the direction value.

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So we say direction is equal
to direction.normalized.

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This is another function
of the vector 2 type

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that's going to limit
the length of the vector to one.

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With these two lines, the ship will
not move faster when going diagonally.

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These two lines also
work great with a gamepad,

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if you are working with a joystick
and using analog input.

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There's one small little bug
that we want to address,

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that if you move to the left and stop,

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the ship goes back
to looking to the right.

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One thing we can do
is only change the rotation in our code

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when the ship is actually moving
or when there's an input direction.

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So we're going to add a line before it.

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We're going to say,
"if direction.length is greater than zero"

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or we can use
the shorthand, "if direction"

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the computer will understand
that we want a vector

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with a length greater than zero.

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We can select the line below
and press the tab key

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to increase its indent level

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to run it only if the direction vector

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has a length greater than zero.

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In that case, we rotate the ship.

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You can now try the game and move

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and when you stop moving,

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the ship preserves
its current loop direction.

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With that, in the next video,

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we'll add a boosting mechanic to the ship.

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Which will be a great opportunity
to look at signals,

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another very important feature in Godot.

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See you there.