Develop Reference

LibGDX Tiled (TMX) Maps + Scene2D, bugs when rendering both

So I've recently started tinkering with LibGDX (desktop only, at the moment) in Java. I'm mildly experienced with other type of OGL libraries in other languages (namely SFML in C++) and quite experienced with the Java language itself, so I tackled LibGDX pretty confidently; and while the results were mostly positive, there's a bug that I just can't figure out.
What I want to achieve is simple: draw a map (Tiled .tmx), draw a Sprite (soon-to-be "player") inbetween layers 1 and 2, and render a couple of GUI widgets on top of all that, using a scene2D stage. I've managed to achieve this partially.
Here's my Game class, it's pretty messy from so much switching things around just to try, but it's pretty clear what it attempts to do:
public class Game extends ApplicationAdapter
{
private SpriteBatch batch;
private Texture img;
private Sprite playerSprite;
private TiledMap tiledMap;
private OrthographicCamera camera;
private OrthogonalTiledMapRenderer tiledMapRenderer;
private Stage stage;
#Override
public void create () {
batch = new SpriteBatch();
img = new Texture("trchar000.png");
playerSprite = new Sprite(img, 0, 0, 32, 48);
playerSprite.setPosition(32, 192);
InputHandler.init();
Gdx.input.setInputProcessor(new InputHandler());
stage = new TestStage(playerSprite);
// inputs
InputMultiplexer im = new InputMultiplexer(stage, new InputHandler());
Gdx.input.setInputProcessor(im);
// tiles
camera = new OrthographicCamera();
camera.setToOrtho(false, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
camera.update();
tiledMap = new TmxMapLoader().load("map2.tmx");
tiledMapRenderer = new OrthogonalTiledMapRenderer(tiledMap);
}
#Override
public void render () {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glBlendFunc(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
camera.update();
tiledMapRenderer.setView(camera);
int[] groundLayers = {0};
int[] topLayers = {1};
// render layer1 -> player -> layer 2
// the .tmx map doesn't have any other layers (just those 2)
tiledMapRenderer.render(groundLayers);
// removing these 3 lines solves the issue, but doesn't render the player
// I've also tried using my regular SpriteBatch instance; same results
// Also, I tried creating a class that extends OrthogonalTiledMapRenderer and overriding the render() method, so that it would draw the player inbetween layers, but again, same results.
tiledMapRenderer.getBatch().begin();
tiledMapRenderer.getBatch().draw(playerSprite, playerSprite.getX(), playerSprite.getY());
tiledMapRenderer.getBatch().end();
tiledMapRenderer.render(topLayers);
batch.begin();
// just to try, I'm rendering the stage here (not calling it's draw() method). Removing this for loop solves the issue, but doesn't render the GUI
for(Actor a : stage.getActors())
a.draw(batch, 1);
batch.end();
}
#Override
public void dispose () {
batch.dispose();
img.dispose();
tiledMapRenderer.dispose();
stage.dispose();
}
}
Also, here's my TestStage class:
public class TestStage extends Stage {
private Skin skin;
private BitmapFont newDefaultFont;
public TestStage(Sprite player)
{
super(new ScreenViewport());
// skin
FreeTypeFontGenerator freeTypeFontGenerator = new FreeTypeFontGenerator(Gdx.files.internal("segoeui.ttf"));
FreeTypeFontGenerator.FreeTypeFontParameter parameter = new FreeTypeFontGenerator.FreeTypeFontParameter();
parameter.size = 14;
newDefaultFont = freeTypeFontGenerator.generateFont(parameter);
skin = new Skin();
skin.add("default-font", newDefaultFont, BitmapFont.class);
FileHandle fileHandle = Gdx.files.internal("uiskin.json");
FileHandle atlasFile = fileHandle.sibling("uiskin.atlas");
if (atlasFile.exists()) {
skin.addRegions(new TextureAtlas(atlasFile));
}
skin.load(fileHandle);
final TextButton button = new TextButton("This is a Button", skin, "default");
button.setPosition(250, 250);
button.setWidth(150);
button.setHeight(40);
final Label lbl = new Label("Test", skin);
this.addActor(lbl);
this.addActor(button);
}
}
Now here's the deal; this is what it looks like if a try to render everything (as shown in my Game class' render() method):
Image 1
The player, GUI, and layer 2 are rendered correctly, but the layer 1 is all bugged out, and I can't figure out why.
Now, here's how it looks like if a don't render the player, removing the line
tiledMapRenderer.getBatch().draw(playerSprite, playerSprite.getX(), playerSprite.getY());
Image 2
Everything renders fine.
Also, here's what it looks like if I decide not to render the stage actors, commenting this loop:
for(Actor a : stage.getActors())
a.draw(batch, 1);
Image 3
Again, everything renders fine.
The only other classes in my project are the default DesktopLauncher class, and an InputProcessor which I'm sure has nothing to do with this.
This is my first question here ever; I just can't figure this out.
Thanks in advance.

LibGDX Game Pause State: Animation flicker/bug

Im trying to implement a pause option for my following game. By pressing the back button my game should go to the updatePause() method. But instead it renders the latest 2-3 frames repeatedly. Making it look like it's "flickering".
By trying to prevent this I've added (in the comments) non-continously rendering which prevented the flickering. But then Im facing the problem that pressing the back-button more than once will render another frame. (one of those flickering frames). This is my code structure in short:
public class GameScreen implements Screen {
private static final int GAME_RUNNING = 0;
private static final int GAME_PAUSED = 1;
private static final int GAME_OVER = 2;
private static final int GAME_LEVEL_END = 3;
private int gameState;
private GdxGame game;
//create()
public GameScreen(final GdxGame game) {
//create all the stuff
}
#Override
public void render(float deltaTime) {
switch (gameState) {
case GAME_RUNNING:
updateRunning(deltaTime);
break;
case GAME_PAUSED:
updatePause(deltaTime);
break;
case GAME_OVER:
updateGameOver();
break;
}
}
public void updateRunning(float deltaTime) {
//draw section
if (gameState == GAME_RUNNING) {
game.batch.begin();
//Draw some stuff
game.batch.end();
//move section
handleInput();
}
}
public void updatePause(float deltaTime) {
//Gdx.graphics.setContinuousRendering(false);
//resume
if (Gdx.input.isTouched()) {
gameState = GAME_RUNNING;
//Gdx.graphics.setContinuousRendering(true);
return;
}
}
private void handleInput() {
//catch back button
Gdx.input.setCatchBackKey(true);
if (Gdx.input.isKeyJustPressed(Input.Keys.BACK)) {
gameState = GAME_PAUSED;
return;
}
}
}
Any tips to prevent the flickering?

The render() method is supposed to draw something to the screen. If it doesn't, then the contents of the back buffer will be undefined (so may contain a previous frame) and you get this flicker.
Disabling continuous rendering sounds like a good approach. Alternatively, continue drawing even if the game is paused.

As Thomas points out in his answer. It should be drawing every frame.
I haven't see you draw anything on screen yet, so backbuffer might just contain junk information. One way to solve this is to always clear the screen at the top of render(). This means when you switch immediately to another game state, it will make sure that screen is clear and no flickering result as you experienced.
public void render(float deltaTime) {
// clear screen
Gdx.gl.glClearColor(0f, 0f, 0f, 1.0f);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
...
}

As Thomas said: continue drawing is a way to fix it. So I drew the latest frame and disabled continous rendering after that. The result is having no bug at all and giving the CPU a rest.

LibGDX visibility

Is there a way to check if my sprite is visible? For instance I have a specific sprite I want to appear only IF this other sprite isn't visible. Example "You Win" will only appear if you win the game and the "You Lose" sprite isn't already on the screen. Thanks!

Visibility of sprite can be maintained by extending Sprite class. Add data member in your extended Sprite Class and at run-time check your sprite is visible of not.
you can also fulfill your requirement by this :
private Sprite win,loose;
private SpriteBatch spriteBatch;
private DialogType dialogType;
#Override
public void create () {
dialogType=DialogType.NONE;
spriteBatch=new SpriteBatch();
win=new Sprite(...);
loose=new Sprite(...);
}
#Override
public void render(float delta) {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
spriteBatch.begin();
...
...
if(dialogType==WIN){
win.draw(spriteBatch);
}else if(dialogType==LOOSE){
loose.draw(spriteBatch);
}
spriteBatch.end();
}
public enum DialogType {
NONE,WIN,LOOSE
}

Seems like an overwhelm to do what you are trying to do, like I said in the comment with a simple boolean win,loose; you pretty much cover your example, or like other comment said you should not track the game state according with some sprite visibility make a enum and track the game state instead, like the other answer, BUT ima give you a solution
Use Image instead...
Image image = new Image(texture);
image.setBounds(0,0,100,100); // set x,y,width,height
stage.add(image); //add to stage
image.setVisible(false); //make it invisible
image.setVisible(true); //make it visible
image.isVisible(); //check if is visible

LibGDX - Stage.setViewport(new Viewport()) black screen

For organization's sake, I use multiple scenes for my game and rather than having each scene have a constructor that receives a Viewport (my game is scalable), I would like to set each stage's viewport separate of the constructor, then after the viewport is set, add the actors. In the main class, it would happen like this:
public void setStage(Stage s)
{
if(currentStage != null)
currentStage.dispose();
currentStage = s;
currentStage.setViewport(view);
}
To make this go fluidly, each stage has an init method that is called within an overriden setViewport:
#Override
public void setViewport(Viewport v)
{
super.setViewport(v);
init();
}
However, all this gives me is a black screen... I have tried updating the camera and viewport, but no avail (note that the actors are having their render methods called).
Why am I getting this black screen and how do I fix it? If it's not possible I'll just revert to using the constructor.

If I understood correctly you want to do this:
Stage stage1 = new Stage();
stage1.getViewport().update(width, height);
rather than this:
Stage stage1 = new Stage (new StretchViewport(width, height)); // It doesn't have to be StretchViewport
In the first case (what you are trying to do) a ScalingViewport will be costructed automatically for you with dimensions of the Gdx.graphics and an orthographic camera and acts like a StretchViewport. Why not using the second case directly where you pass the viewport you want. You can always alter your viewport whenever you want by calling stage1.getViewport().update(width, height);
or by calling stage1.setViewport(width, height, false); in older Libgdx versions.
Viewport has changed recently so if you can extend Viewport class to Override the update method maybe you can achieve what you want:
public class ViewportExtendClass extends StretchViewport{
public ViewportExtendClass(float worldWidth, float worldHeight) {
super(worldWidth, worldHeight);
}
#Override
public void update (int screenWidth, int screenHeight, boolean centerCamera) {
super.update(screenWidth, screenHeight, centerCamera);
// DO YOUR INITIALIZATION HERE
}
}
From your main class you create new stage :
Stage stage1 = new Stage (new ViewportExtendClass (width, height));
and then you call :
stage1.getViewport().update(width, height);
Like this you can alter stage viewport and re initialize your assets.

#Override
public void setViewport(Viewport v)
{
super.setViewport(v);
this.getViewport().update(Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), false);
Camera c = this.getViewport().getCamera();
c.position.set(c.viewportWidth/2, c.viewportHeight/2, 0);
init();
}
This works, but you should also be able to update the Viewport like that at the begin of your application, if you continue to use the same one. I set the position like that instead of centering because some of my Stages will be larger than the screen.

libGDX SpriteCache: transparency on images not displayed properly

I'm developing a Tower Defense game using libGDX. I've just started and I am able to display the path, the "environment" and the enemies walking along the path.
I displayed the environment using a SpriteBatch-Object, like this:
public LevelController(Level level) {
spriteBach = new SpriteBach();
atlas = new TextureAtlas(Gdx.files.internal("images/textures/textures.pack"));
}
public void setSize() {
spriteBatch.setProjectionMatrix(this.cam.combined);
}
public void render() {
spriteBatch.begin();
drawTowerBases();
spriteBatch.end();
}
private void drawTowerBases() {
// for each tower base (=environment square)
TextureRegion towerBaseTexture = atlas.findRegion("TowerBase");
if(towerBaseTexture != null) {
spriteBatch.draw(towerBaseTexture, x, y, 1f, 1f);
}
}
This is working properly and the textures are displayed well: Tower Defense using spriteBatch
Now, I was wondering if it is possible to cache the background. Because it stays the same, there is no need to calculate it every time. I've found the SpriteCache through Google-Search. So I changed the code as follows:
public LevelController(Level Level) {
spriteCache= new SpriteCache();
atlas = new TextureAtlas(Gdx.files.internal("images/textures/textures.pack"));
spriteCache.beginCache();
this.drawTowerBases();
this.spriteCacheEnvironmentId = spriteCache.endCache();
}
public void setSize() {
this.cam.update();
spriteCache.setProjectionMatrix(this.cam.combined);
}
public void render() {
spriteCache.begin();
spriteCache.draw(this.spriteCacheEnvironmentId);
spriteCache.end();
}
private void drawTowerBases() {
// for each tower base (=environment square)
TextureRegion towerBaseTexture = atlas.findRegion("TowerBase");
if(towerBaseTexture != null) {
spriteCache.add(towerBaseTexture, x, y, 1f, 1f);
}
}
And now the game looks like this: Tower Defense using spriteCache
For me it seems as if the transparency is not rendered properly. If I take images without transparency, everything works fine. Does anyone have an idea, why this happens and how I can fix this?
Thank you in advance.

Taken from the SpriteCache documentation:
Note that SpriteCache does not manage blending. You will need to enable blending (Gdx.gl.glEnable(GL10.GL_BLEND);) and set the blend func as needed before or between calls to draw(int).
I guess there is not much more to say.