We Keep Coding

Resizing TextButton LibGDX

I'm kinda new to LibGDX.
I'm just learning the ropes.
Trying to get a basic TextButton to display at a reasonable size on screen.
Working exclusively on Android IDE (AIDE).
Using only default skins and what-not, I've tried to set width and height as well as setScale() but only the text size seems to increase on the command.
What am I doing wrong?
https://oi1161.photobucket.com/albums/q501/StudioGilliam/Screenshot_20190423-184819_LibGDXButtonsTest.jpg
public class MyGdxGame implements ApplicationListener
{
private Stage stage;
private Table table;
private TextButton btn;
#Override
public void create()
{
stage = new Stage(new ScreenViewport());
Gdx.input.setInputProcessor(stage);
table = new Table();
table.setBounds(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
TextButton.TextButtonStyle style = new TextButton.TextButtonStyle();
style.font = new BitmapFont();
btn = new TextButton("Button", style);
btn.pad(20);
btn.setTransform(true);
btn.setScale(5.0f);
btn.setTouchable(Touchable.enabled);
table.add(btn);
table.debug();
stage.addActor(table);
}
#Override
public void render()
{
Gdx.gl.glClearColor(0, 1, 1, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
stage.act();
stage.draw();
}
#Override
public void dispose()
{
stage.dispose();
}
#Override
public void resize(int width, int height){}
#Override
public void pause(){}
#Override
public void resume(){}
}
EDIT:
I realised that parent objects like stages and tables control the properties of their children, so I added:
table.add(btn).width(300).height(100);
And now it looks better but the text is way off centre...
https://oi1161.photobucket.com/albums/q501/StudioGilliam/Screenshot_20190423-191104_LibGDXButtonsTest.jpg

On a Textbutton, you should use setFontScale() and pack() to resize the button to the font size.
However, for supporting different screen sizes without any own coding, consider using FitViewport/ExtendViewport

Libgdx reducing calls and optimize the game

Am trying to reduce number of calls being made everytime a Screen is called on my game in a bid to make my game faster and I noticed I do alot the same calculation on every screen..how can i avoid this?
I do this in practically every screen
public class ****Screen implements Screen {
#Override
public void show() {
float screenWidth = Gdx.graphics.getWidth();
float screenHeight = Gdx.graphics.getHeight();
float gameWidth = 360;
float gameHeight = screenHeight / (screenWidth / gameWidth);
midPointY = (int) (gameHeight / 2);
cam = new OrthographicCamera();
cam.setToOrtho(true, gameWidth, gameHeight);
viewport = new FitViewport(gameWidth, gameHeight, cam);
viewport.apply();
stage = new Stage(viewport);
Gdx.input.setInputProcessor(stage);
yet I have a GameClass..How can I implement the above in my gameclass(below) and only have to call it once?...
public class Start extends Game {
#Override
public void create() {
float screenWidth = Gdx.graphics.getWidth();
float screenHeight = Gdx.graphics.getHeight();
float gameWidth = 360;
float gameHeight = screenHeight / (screenWidth / gameWidth);
assets = new AssetLoader();
assetManager = new AssetManager();
camera = new OrthographicCamera();
camera.setToOrtho(true, gameWidth, gameHeight);
//initialize screens here
mainMenu = new MenuScreen(this);
loadingScreen = new LoadingScreen(this);
gameScreen = new GameScreen(this);
.......
//call assets
AssetLoader.load();
//start mainmenu...
this.setScreen(mainMenu);
}

First i have to tell you actualy this wont speed up your game.
If you change screen every 20 seconds then that means game does calculations 1 frame per 1200 frames.
However i am same like you and really looking for most optimize ways while doing game.
I found a solution for this case.
You can pass objects that you use in all screens, from game class to screen class.
Screen class
public class MainMenuScreen implements Screen {
public MainMenuScreen(OrthographicCamera camera) {
this.camera=camera;
}
//...Rest of class omitted for succinctness.
}
Game class
public class Starts extends Game {
OrthographicCamera camera;
public void create() {
camera=new OrthographicCamera();
camera.setToOrtho(false, 800, 480);
this.setScreen(new MainMenuScreen(camera));// change screen and pass camera to new screen.
}
}
Or you can even pass the whole game class like this.
public class MainMenuScreen implements Screen {
final Starts game;
public MainMenuScreen(final Starts game) {
this.game = game;
}
#Override
public void render(float delta) {
Gdx.gl.glClearColor(0, 0, 0.2f, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
game.camera.update();
game.batch.setProjectionMatrix(game.camera.combined);
game.batch.begin();
game.font.draw(...);
game.font.draw(...);
game.batch.end();
if (Gdx.input.isTouched()) {
game.setScreen(new AnotherScreen(game));
dispose();
}
}
}
just need to call like this in game class. So you can use stage batches fonts etc. of game in all screens.
this.setScreen(new MainMenuScreen(this));

I assume you mean you want to shorten the little hiccup you get when switching screens. (Your game's frame rate is not affected by this.)
Easy way: move that code from show to the constructor of each screen class.
However, it is wasteful to be creating a new Stage for each Screen without passing it a SpriteBatch, because you are essentially instantiating three separate SpriteBatches, which are heavy objects (they have a big array for the mesh data, a big mesh on the GPU, and have to compile a shader).
You can instantiate shared objects in your Game class and pass them into the constructors of your Screens like this:
public class Start extends Game {
SpriteBatch spriteBatch;
#Override
public void create() {
//...
//initialize screens here
spriteBatch = new SpriteBatch(); //must be disposed in dispose()
mainMenu = new MenuScreen(this, spriteBatch);
loadingScreen = new LoadingScreen(this, spriteBatch);
gameScreen = new GameScreen(this, spriteBatch);
//...
}
}
Update your Screens' constructors accordingly and pass the sprite batch into the stage constructors. Viewports and cameras are lightweight, so I wouldn't bother with moving those up to the Game class unless it helps make your code more maintainable.
By the way, you're kind of abusing FitViewport by pre-calculating the aspect ratio. The point of Viewports is that you don't need to calculate anything when setting up. Use new ExtendViewport(360, 1, cam) to get the same thing you're doing without the calculations. And make sure you're updating it in resize().

(LibGDX) Displaying a screenshot from previous FrameBuffer on a Stage

I'm trying to get a screenshot to display on the background of a pause menu.
My screenshot method uses ScreenUtils.getFrameBufferPixmap() to get the screenshot; I got it from here.
My code for the pause screen is as follows:
public class CEscapeScreen implements CScreen {
private final Stage stage;
private class BGActor extends Actor {
Pixmap pixmap = CUtil.getScreenshot(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), false);
Texture t = new Texture(pixmap);
#Override
public void draw(Batch batch, float alpha) {
batch.draw(t, 0, 0);
}
}
public CEscapeScreen(CGame g) {
Actor bgActor = new BGActor();
stage = new Stage();
final TextButton quitButton = new TextButton("Quit to Main Menu", CUi.getUISkin(), "default");
...
table.add(quitButton);
stage.addActor(bgActor);
stage.addActor(table);
}
#Override
public void display() {
stage.draw();
}
}
The display method is called every frame by the current Screen the program is on.
What I'm trying to accomplish is to get a screenshot of the screen before the pause screen stage is drawn, and then draw that screenshot behind the quitButton.
Every other Screen clears and makes a new Stage like this one.
The problem I'm having, is that only the quitButton appears on the Escape Menu. Why does this happen?

LibGDX - how do I make my text centered?

I'm new to LibGDX and I am taking it slowly. I'm still trying to understand most things which is why typically google searches don't help due to the fact that their too complicated. I have a main menu that has text that I want centered no matter what the screen size is. Here is the code that I have for that menu.
public class Menu implements Screen {
SlingshotSteve game;
OrthographicCamera camera;
public Menu(final SlingshotSteve gam) {
this.game = gam;
camera = new OrthographicCamera();
camera.setToOrtho(false, 800, 480);
}
#Override
public void render(float delta) {
Gdx.gl.glClearColor(0, 0, 0.2f, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
camera.update();
game.batch.setProjectionMatrix(camera.combined);
game.batch.begin();
game.font.draw(game.batch, "Welcome to Slingshot Steve!!! ", 100, 150);
game.font.draw(game.batch, "Tap anywhere to begin!", 100, 100);
game.batch.end();
if (Gdx.input.isTouched()) {
game.setScreen((Screen) new GameScreen(game));
dispose();
}
}
#Override
public void resize(int width, int height) {
}
#Override
public void show() {
}
#Override
public void hide() {
}
#Override
public void pause() {
}
#Override
public void resume() {
}
#Override
public void dispose() {
}
}

I'm here to save you!
To get width / height from a String drawn with your BitmapFont you can utilize this super nice method:
game.font.getBounds(String string)
And to use it in your case, it would be something like this:
game.font.getBounds("Tap anywhere to begin!").width / 2;
Cheers!

It is possible to do it the way Nine Magics suggested, however one would usually do it via a Stage, which is part of scene2d.
More specifically one would use scene2d.ui which is a bunch of Actors like Button, Image, Label etc. You can attach a ClickListener to a Button for example and react on this event.
Furthermore, for layouting there is one very powerful Actor, namely Table which you can very easily use to center things on the screen.
Some very minimalistic code:
// do this once, in create() or show()
Skin skin = new Skin("uiskin.json"); // get the demo skin from the libgdx test resources
Stage stage = new Stage();
Table table = new Table(skin);
table.add("Welcome to Slingshot Steve!!!");
table.row();
table.add("Tap anywhere to begin!");
stage.addActor(table);
// do this in your render loop
stage.act();
stage.draw();
You can find the "default" skin resources here. You need to get all the uiskin.* files.

Reuse code when using screens in Libgdx

From what I understand when reading other peoples code on how to make different screens. You do a main handler class sort of... And then create a new class for each screen.
The thing that confuses me is that whenever you create a new screen, you have to redefine everything that's going to be rendered, like SpriteBatch, sprites, fonts, etc. Is there any way to reuse these kind of things in all screens? I mean, if I have 10 screens, and want to be able to draw text on every screen. Is it really good programming practice to make a new BitmapFont for all 10 screen classes?

I've created an Abstract Screen class that contains all the common objects for a screen, every one of my screens extend this abstract class. And that looks like this:
public abstract class AbstractScreen implements Screen {
protected final Game game;
protected InputMultiplexer multiInputProcessor;
protected ScreenInputHandler screenInputHandler;
protected Stage uiStage;
protected Skin uiSkin;
public AbstractScreen(Game game) {
this.game = game;
this.uiStage = new Stage();
this.uiSkin = new Skin();
this.screenInputHandler = new ScreenInputHandler(game);
this.multiInputProcessor = new InputMultiplexer();
multiInputProcessor.addProcessor(uiStage);
multiInputProcessor.addProcessor(screenInputHandler);
Gdx.input.setInputProcessor(multiInputProcessor);
}
private static NinePatch processNinePatchFile(String fname) {
final Texture t = new Texture(Gdx.files.internal(fname));
final int width = t.getWidth() - 2;
final int height = t.getHeight() - 2;
return new NinePatch(new TextureRegion(t, 1, 1, width, height), 3, 3, 3, 3);
}
#Override
public void render (float delta) {
Gdx.gl.glClearColor(0.2f, 0.2f, 0.2f, 1);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
uiStage.act(Math.min(Gdx.graphics.getDeltaTime(), 1 / 30f));
uiStage.draw();
Table.drawDebug(uiStage);
}
#Override
public void resize (int width, int height) {
}
#Override
public void show() {
}
#Override
public void hide() {
dispose();
}
#Override
public void pause() {
}
#Override
public void resume() {
}
#Override
public void dispose() {
uiStage.dispose();
uiSkin.dispose();
}
}
When I want to create a new class I just extend the abstract screen and add what I need. For example I have a basic credits screen, I just need to create the components but the abstract screen draws it:
public class CreditsScreen extends AbstractScreen {
public CreditsScreen(final Game game) {
super(game);
// Generate a 1x1 white texture and store it in the skin named "white".
Pixmap pixmap = new Pixmap(1, 1, Format.RGBA8888);
pixmap.setColor(Color.WHITE);
pixmap.fill();
uiSkin.add("white", new Texture(pixmap));
// Store the default libgdx font under the name "default".
BitmapFont buttonFont = new BitmapFont();
buttonFont.scale(scale);
uiSkin.add("default", buttonFont);
// Configure a TextButtonStyle and name it "default". Skin resources are stored by type, so this doesn't overwrite the font.
TextButtonStyle textButtonStyle = new TextButtonStyle();
textButtonStyle.up = uiSkin.newDrawable("white", Color.DARK_GRAY);
textButtonStyle.down = uiSkin.newDrawable("white", Color.DARK_GRAY);
textButtonStyle.checked = uiSkin.newDrawable("white", Color.BLUE);
textButtonStyle.over = uiSkin.newDrawable("white", Color.LIGHT_GRAY);
textButtonStyle.font = uiSkin.getFont("default");
uiSkin.add("default", textButtonStyle);
// Create a table that fills the screen. Everything else will go inside this table.
Table table = new Table();
table.setFillParent(true);
uiStage.addActor(table);
table.debug(); // turn on all debug lines (table, cell, and widget)
table.debugTable(); // turn on only table lines
// Label
BitmapFont labelFont = new BitmapFont();
labelFont.scale(scale);
LabelStyle labelStyle = new LabelStyle(labelFont, Color.BLUE);
uiSkin.add("presents", labelStyle);
final Label myName = new Label("Credits and all that stuff", uiSkin, "presents");
table.add(myName).expand().center();
}
}
I also have a single class that handles the input for all the screens, the specific purpose for this is to handle how the back button works around the different screens. And this input handler class is created in the abstract class.
public class ScreenInputHandler implements InputProcessor {
private final Game game;
public ScreenInputHandler(Game game) {
this.game = game;
}
#Override
public boolean keyDown(int keycode) {
if(keycode == Keys.BACK || keycode == Keys.BACKSPACE){
if (game.getScreen() instanceof MainMenuScreen) {
Gdx.app.exit();
}
if (game.getScreen() instanceof GameScreen) {
World.getInstance().togglePause(false);
}
if (game.getScreen() instanceof CreditsScreen) {
game.setScreen(new MainMenuScreen(game));
}
}
return false;
}
}