Develop Reference

How to extend the background in LibGdx for top down game?

What is the proper way to extend the background in top down game? I used LibGdx framework. Any idea or tutorial for top down game.My background is in PNG format and screen of 720x1280 portrait.I had a problem in extending the background.I want the camera follow the character and the background will extend. How could I do that? Here is the Screen shot of
https://i.stack.imgur.com/jl03R.png
Here is my code
To display background I used this
//background
Background = new Texture(Gdx.files.internal("floor.png")); //File from assets folder
Background.setWrap(Texture.TextureWrap.Repeat, Texture.TextureWrap.Repeat);
bgsprite = new Sprite(Background);
In render
spriteBatch.draw(Background,0,100,0, srcy, Gdx.graphics.getWidth(),Gdx.graphics.getHeight());
srcy +=3;
The background is scrolling but the camera don't follow the player(cat)
Source code for GameScreen
http://pastebin.com/Dxfx9f65
Thank's and Advance any help or suggestion are much appreciated. :)

Use two identical texture background. Each the size of the screen It can be the same file. It is important that are docked vertically. Move of at the same time. Alternately changing with each other.
Sample code:
declaration:
Texture background1, background2;
SpriteBatch batch;
float yMax, yCoordBg1, yCoordBg2;
final int BACKGROUND_MOVE_SPEED = 100; // pixels per second. Put your value here.
creation:
Background1 = new Texture(Gdx.files.internal("floor.png"));
Background2 = new Texture(Gdx.files.internal("floor.png")); // identical
yMax = 1280;
yCoordBg1 = yMax*(-1); yCoordBg2 = 0;
in method render:
yCoordBg1 += BACKGROUND_MOVE_SPEED * Gdx.graphics.getDeltaTime();
yCoordBg2 = yCoordbg1 + yMax; // We move the background, not the camera
if (yCoordBg1 >= 0) {
yCoordBg1 = yMax*(-1); yCoordBg2 = 0;
}
batch.begin();
batch.draw(background1, 0, yCoordBg1);
batch.draw(background2, 0, yCoordBg2);
batch.end();
The background can be made in the format jpg - will spend less memory.

Text not displaying in LibGdx Java

I am trying to add text for debugging purposes in my program. I call the players debugDraw method like so in the main class:
public void create () {
//Initialize essentials
cam = new OrthographicCamera(Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
cam.setToOrtho(false);
rend = new ShapeRenderer();
rend.setAutoShapeType(true);
batch = new SpriteBatch();
// Initialize Entities
player = new Player(new Vector2(100, 100), new Vector2(100,100));
enemy = new Enemy(new Vector2(100, 100), new Vector2(100,10));
}
#Override
public void render () {
//Update player
player.update();
//Update camera then set matrix of batch
cam.update();
batch.setTransformMatrix(cam.combined);
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
// ShapeRenderer begin
rend.begin();
player.render(rend);
enemy.render(rend);
rend.end();
// ShapeRenderer end
// SpriteBatch begin
batch.begin();
player.renderDebugText(batch);
batch.end();
// SpriteBatch end
}
Here is the entity class which is the parent class to player:
public Entity(Vector2 coords, Vector2 dims){
//Assign constructors
position = coords;
dim = dims;
//For debugging purposes of all entities
debugText = new BitmapFont();
debugText.setColor(Color.WHITE);
}
public void renderDebugText(SpriteBatch batch){
debugText.draw(batch, "Vel.x: " + vel.x, 100, 100);
}
However when I run the program, I just get my normal screen with no text at all. I can't seem to figure out why this isn't working. Any help is extremely appreciated.

Nothing immediately looks wrong with the code you posted, so here's a few ideas;
The default BitmapFont is 15pt, if this is drawn at 15px height then it could be very small if you force your game to a high resolution, like Full-HD. My current project is Full-HD and the font I use looks just about right at 45px, so you could try scaling yours by a factor of 3 or 4. E.g. use this after initialising your font;
bitmapFont.getData().setScale(3);
Your Camera should also have the virtual/viewport dimensions, so if you are forcing a particular resolution then you should pass in your virtual dimensions instead.
As #Tenfour04 has suggested, you should try to avoid multiple instances of the same font, so instead of initialising your font in the Entity class, initialise it in your main game and pass it through the Entity constructor. I can't see how this would fix your issue though as this would be purely for performance.

I made a very simple mistake, but from how much code I posted, it is easily missed. On the line where I put
batch.setTransformMatrix(cam.combined);
it should be replaced with
batch.setProjectionMatrix(cam.combined);
Then all errors go away, sorry, I don't know why it took me so long to figure out. Thanks for all the help!

Libgdx / Scene2D Scaling not working

im currently developing a little duengon crawler and i wanna try to implement a healthbar using Scene2D. But theres a problem ... when i try to set the size of the progressbar its ever and ever the same size, doesnt matter if i do :
healthBar.setWidth(1f);
healthBar.setHeight(0.25f);
or
healthBar.setWidth(100);
healthBar.setHeight(25);
What im doing wrong ?? Heres how i created the stage ^^
camera = new OrthographicCamera(0,0);
camera.setToOrtho(false,Gdx.graphics.getWidth()/Box2dVars.UNIT,Gdx.graphics.getHeight()/Box2dVars.UNIT);
camera.zoom = (float) 0.75;
port = new ExtendViewport(camera.viewportWidth, camera.viewportHeight, camera);
stage = new Stage(port);
I also act and draw the stage every tick in the render method. Heres how i create the ProgressBar :
skin = new Skin(Gdx.files.internal("Scene2D-Skins/uiskin.json"));
healthBar = new ProgressBar(0, 100, 0.5f, false, skin, "default");
healthBar.setWidth(1f);
healthBar.setHeight(0.25f);
healthBar.setPosition(this.getPosition().x, this.getPosition().y);
this.gameScreen.stage.addActor(healthBar);
Did you see a mistake ?? What did i forgot ? :/ I would be happy about some help !

Android Collision Detection?

Here is the code that I use for the moving ImageView:
int x=brickimg.getRight()-brickimg.getLeft();
int y=brickimg.getBottom()-brickimg.getTop();
final TranslateAnimation translate = new TranslateAnimation(
Animation.ABSOLUTE,x1, Animation.ABSOLUTE,
-2000, Animation.ABSOLUTE,0,
Animation.ABSOLUTE,y);
translate.setDuration(1200);//speed of the animation
translate.setFillEnabled(true);
translate.setFillAfter(true);
//brickimg.startAnimation(translate);
//2nd brick animation
int x1=brickimg2.getRight()-brickimg2.getLeft();
int y1=brickimg2.getBottom()-brickimg2.getTop();
final TranslateAnimation secondone = new TranslateAnimation(
Animation.ABSOLUTE,x1, Animation.ABSOLUTE,
-2000, Animation.ABSOLUTE,0,
Animation.ABSOLUTE,y1);
secondone.setDuration(1200);//speed of the animation
secondone.setFillEnabled(true);
secondone.setFillAfter(true);
This is for two images. Here is the code that I tried to use for collision detection:
Rect rc1 = new Rect();
brickimg.getDrawingRect(rc1);
Rect rc2 = new Rect();
playerimage.getDrawingRect(rc2);
if (rc1.intersect( rc2)) {
playerimage.setVisibility(View.GONE);
}
However, the only thing that happens is that playerimage turns invisible when the app starts. It doesn't turn invisible again. One of the images doesn't move, and the other moves across the screen towards the one that doesn't move (using the code I put above). The image that doesn't move turns invisible immediately, and not when the second image touches it. I'm trying to make it so it does something when it touches the moving image. Besides this, I've also tried .getHitRect and I've also tried .intersects instead of .intersect, but none of it works. The moving image is an ImageView, not a sprite. Is there another option?

AndEngine GLES 2 - black screen, no errors

I am writing a game for Android using AndEngine GLES 2. Everything was working properly - I had a background image, there were sprites moving around and even some music - until recently I tried something new (I wanted to be able to switch between two different scenes) when the display turned black.
I could still execute the game and there were no error shown. All log entries I made during the game were shown, even the music was playing so I knew the game was running "properly", but I couldn't see any image. Nothing. All black.
So I thought, changing everything back to before this "error" appeared, would do the trick. But still the screen is black.
I even tried commenting everything out but the background image - nothing.
Now if it is not too much to ask, could anyone please look over this short piece of code and tell me what is wrong there?
This are the variables I use:
private SmoothCamera camera;
private BitmapTextureAtlas bitmapTextureAtlas;
private Scene scene;
private Sprite background;
The EngineOptions I never changed, so they should be alright.
#Override
public EngineOptions onCreateEngineOptions() {
float positionX = 80f; // horizontal (x) position of the camera
float positionY = 280f; // vertical (y) position of the camera
float velocityX = 200f; // velocity of the horizontal camera movement
float velocityY = 200f; // velocity of the vertical camera movement
float zoomFactor = 1f; // the camera's zoom Factor (standard := 1)
this.camera = new SmoothCamera(positionX, positionY, this.getWindowManager().getDefaultDisplay().getWidth(), this.getWindowManager().getDefaultDisplay().getHeight(), velocityX, velocityY, zoomFactor);
EngineOptions options = new EngineOptions(true, ScreenOrientation.LANDSCAPE_SENSOR, new RatioResolutionPolicy(this.camera.getWidth(), this.camera.getHeight()), this.camera);
return options;
}
Here I create the TextureAtlas and load a background image.
#Override
protected void onCreateResources() {
// create the TextureAtlas
BitmapTextureAtlasTextureRegionFactory.setAssetBasePath("gfx/");
this.bitmapTextureAtlas = new BitmapTextureAtlas(this.getTextureManager(), 1024, 1600, TextureOptions.NEAREST);
// background
this.background = new Sprite(0, 0, BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(this.bitmapTextureAtlas, this, "background.png", 0, 0, 1, 1), this.getVertexBufferObjectManager());
this.mEngine.getTextureManager().loadTexture(this.bitmapTextureAtlas);
}
And finally the Scene is instantiated and the background gets attached.
#Override
protected Scene onCreateScene() {
this.scene = new Scene();
this.scene.attachChild(this.background);
return this.scene;
}
Now why would this small Activity not show? I forgot: its a SimpleBaseGameActivity.
Well, since AndEngine GLES2 is not running on the emulator, I have to use my phone (Samsung Galaxy GIO) and can't test the app on another machine.
Did anyone stumble upon a similar problem?
Any help is really much appreciated and thank you for your time !
Christoph

I think the problem is here:
this.bitmapTextureAtlas = new BitmapTextureAtlas(this.getTextureManager(), 1024, 1600, TextureOptions.NEAREST);
The dimensions of the Atlas are supposed to be powers of 2.