Scene 2D

1. LibGDX:
Internaliza1on
and
Scene
2D
Jussi
Pohjolainen
Tampere
University
of
Applied
Sciences

2. INTERNALIZATION

3. Support
for
Mul1ple
Languages
• Create
defaults
proper1es
file:
– MyBundle.properties
• Create
other
language
files:
– MyBundle.fi_FI.properties

4. MyBundle.proper1es
title=My Game
score=You score {0}

5. MyBundle_fi.proper1es
title=Pelini
score=Pisteesi {0}

6. In
Java
Locale locale = new Locale("fi");
I18NBundle myBundle =
I18NBundle.createBundle(Gdx.files.internal("MyBundle"), locale);
String title = myBundle.get("title");
String score = myBundle.get("score", 50);

7. Notes
• If
you
don't
specify
locale,
default
locale
is
used
• Charset
is
UTF-­‐8
(without
BOM)
• See:
– hVps://github.com/libgdx/libgdx/wiki/
Interna1onaliza1on-­‐and-­‐Localiza1on

8. SCENE2D

9. Scene2D?
• It’s
op1onal,
you
don’t
need
it.
But
you
may
want
to
use
it.
• May
be
useful
for
"board
games"
• Higher
level
framework
for
crea>ng
games
• Provides
UI
Toolkit
also:
Scene2d.ui
• Tutorial
– https://github.com/libgdx/libgdx/wiki/Scene2d

10. Concepts
• Stage
– “Screens”,
“Stages”,
“Levels”
– Camera
watching
the
stage
– Contains
group
of
actors
• Actors
– “Sprites”

11. Roughly
the
Idea
in
Code
Stage gameStage = new Stage();
// PlayerActor extends Actor { .. }
PlayerActor player = new PlayerActor();
// Let's add the actor to the stage
gameStage.addActor(player);

12. Possibili1es
• Event
system
for
actors;
when
actor
is
touched,
dragged
..
– Hit
detec>on;
dragging
/
touching
within
the
bounds
of
actor
• Ac>on
system:
rotate,
move,
scale
actors
in
parallel
– Also
rota1on
and
scaling
of
group
of
actors

13. Stage
• Stage
implements
InputProcessor,
so
it
can
directly
input
events
from
keyboard
and
touch
• Add
to
your
Applica1onAdapter
– Gdx.input.setInputProcessor(myStage);
• Stage
distributes
input
to
actors
• Use
setViewport
to
set
the
camera
– myStage.setViewPort(...);
• Stage
has
act
method,
by
calling
this,
every
act
method
of
every
actor
is
called

14. Actors
• Actor
has
an
posi1on,
rect
size,
scale,
rota1on…
• Posi1on
is
the
leb
corner
of
the
actor
• Posi1on
is
rela1ve
to
the
actor’s
parent
• Actor
may
have
ac>ons
– Change
the
presenta>on
of
the
actor
(move,
resize)
• Actor
can
react
to
events

15. public class StageGame extends ApplicationAdapter {
// Stage contains hierarcy of actors
private Stage stage;
// We will have player actor in the stage
private BlueBirdActor playerActor;
@Override
public void create () {
// Creating the stage
stage = new Stage();
// Creating the actors
playerActor = new BlueBirdActor();
// add actors to stage
stage.addActor(playerActor);
}
@Override
public void render () {
Gdx.gl.glClearColor(1, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
// Call act on every actor
stage.act(Gdx.graphics.getDeltaTime());
// Call draw on every actor
stage.draw();
}
}

16. public class BlueBirdActor extends Actor {
private Texture texture;
public BlueBirdActor() {
texture = new Texture(Gdx.files.internal("blue-bird-icon.png"));
}
@Override
public void draw(Batch batch, float alpha) {
batch.draw(texture, getX(), getY());
}
@Override
public void act(float delta) {
super.act(delta);
}
}

17. Event
System
• Stage
will
be
responsible
for
gedng
user
input
– Gdx.input.setInputProcessor(stage);
• Stage
will
fire
events
to
actors
• Actor
may
receive
events
if
it
has
a
listener
– actor.addListener(new InputListener()
{ … } );
• Actor
must
specify
bounds
in
order
to
receive
input
events
within
those
bounds!
• To
handle
key
input,
actor
has
to
have
keyboard
focus

18. public class StageGame extends ApplicationAdapter {
// Stage contains hierarcy of actors
private Stage stage;
// We will have player actor in the stage
private BlueBirdActor playerActor;
@Override
public void create () {
// Creating the stage
stage = new Stage();
// Sets the InputProcessor that will receive all touch and key input events.
// It will be called before the ApplicationListener.render() method each frame.
//
// Stage handles the calling the inputlisteners for each actor.
Gdx.input.setInputProcessor(stage);
// Creating the actors
playerActor = new BlueBirdActor();
// add actors to stage
stage.addActor(playerActor);
stage.setKeyboardFocus(playerActor);
}
@Override
public void render () {
Gdx.gl.glClearColor(1, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
// Call act on every actor
stage.act(Gdx.graphics.getDeltaTime());
// Call draw on every actor
stage.draw();
}
}

19. public class BlueBirdActor extends Actor {
private boolean up, down, left, right
public BlueBirdActor() {
addListener(new PlayerListener());
}
@Override
public void act(float delta) {
if(up) {
setY(getY() + speed * delta);
}
}
// InputListener implements EventListener, just override the methods you need
// Also ActorGestureListener available: fling, pan, zoom, pinch..
class PlayerListener extends InputListener {
@Override
public boolean keyDown(InputEvent event, int keycode) {
if(keycode == Input.Keys.UP) {
up = true;
}
return true;
}
@Override
public boolean keyUp(InputEvent event, int keycode) {
if(keycode == Input.Keys.UP) {
up = false;
}
return true;
}
}
}

20. Ac1ons
• Each
actor
has
a
list
of
ac1ons
• Updated
on
every
frame
(act-­‐method)
• Many
ac1ons
available
– MoveToAction
– RotateToAction
– ScaleToAction
• Example
– MoveToAction action = new MoveToAction();
– action.setPosition(300f, 700f);
– action.setDuration(2f);
– actor.addAction(action);

21. Grouping
Ac1ons
in
Sequence
SequenceAction sequenceAction = new SequenceAction();
MoveToAction moveAction = new MoveToAction();
RotateToAction rotateAction = new RotateToAction();
ScaleToAction scaleAction = new ScaleToAction();
moveAction.setPosition(200f, 400f);
moveAction.setDuration(1f);
rotateAction.setRotation(rotate);
rotateAction.setDuration(1f);
scaleAction.setScale(0.5f);
scaleAction.setDuration(1f);
sequenceAction.addAction(moveAction);
sequenceAction.addAction(rotateAction);
sequenceAction.addAction(scaleAction);
actor.addAction(sequenceAction);

22. Grouping
Ac1ons
in
Parallel
ParallelAction parallel = new ParallelAction ();
MoveToAction moveAction = new MoveToAction();
RotateToAction rotateAction = new RotateToAction();
ScaleToAction scaleAction = new ScaleToAction();
moveAction.setPosition(200f, 400f);
moveAction.setDuration(1f);
rotateAction.setRotation(rotate);
rotateAction.setDuration(1f);
scaleAction.setScale(0.5f);
scaleAction.setDuration(1f);
parallel.addAction(moveAction);
parallel.addAction(rotateAction);
parallel.addAction(scaleAction);
actor.addAction(parallel);

23. Ac1ons
Complete?
SequenceAction sequenceAction = new SequenceAction();
ParallelAction parallelAction = new ParallelAction();
MoveToAction moveAction = new MoveToAction();
RotateToAction rotateAction = new RotateToAction();
RunnableAction runnableAction = new RunnableAction();
moveAction.setPosition(200f, 400f);
moveAction.setDuration(1f);
moveAction.setInterpolation(Interpolation.bounceOut);
rotateAction.setRotation(rotate);
rotateAction.setDuration(1f);
runnableAction.setRunnable(new Runnable() {
public void run() {
System.out.println("done!");
}
});
parallelAction.addAction(rotateAction);
parallelAction.addAction(moveAction);
sequenceAction.addAction(parallelAction);
sequenceAction.addAction(runnableAction);

24. Enable
rotate
and
scale
in
drawing
@Override
public void draw(Batch batch, float alpha){
batch.draw(texture,
this.getX(), this.getY(),
this.getOriginX(),
this.getOriginY(),
this.getWidth(),
this.getHeight(),
this.getScaleX(),
this.getScaleY(),
this.getRotation(),0,0,
texture.getWidth(), texture.getHeight(), false, false);
}

25. Grouping
Group group = new Group();
group.addActor(playerActor);
group.addActor(monsterActor);
group.addAction( ... );
stage.addActor(group);

26. CREATING
UI:
SCENE2D.UI

27. Scene2D.UI
• Tutorial
– hVps://github.com/libgdx/libgdx/wiki/Scene2d.ui
• To
quickly
get
started,
add
following
to
your
project
– uiskin.png,
uiskin.atlas,
uiskin.json,
default.fnt
– hVps://github.com/libgdx/libgdx/tree/master/
tests/gdx-­‐tests-­‐android/assets/data
• Tutorial
and
examples
– hVps://github.com/libgdx/libgdx/wiki/Scene2d.ui

28. TextBuVon
example
Skin skin = new Skin( Gdx.files.internal("uiskin.json") );
final TextButton button = new TextButton("Hello", skin);
button.setWidth(200f);
button.setHeight(20f);
button.setPosition(Gdx.graphics.getWidth() /2 - 100f, Gdx.graphics.getHeight()/2
- 10f);
startStage.addActor(button);
Gdx.input.setInputProcessor(startStage);
button.addListener(new ClickListener(){
@Override
public void clicked(InputEvent event, float x, float y){
whichScreen = !whichScreen;
Gdx.input.setInputProcessor(gameStage);
}
});