Develop Reference

How to draw a sprite within the FitViewport view. libgdx

The basic question here is: how to ALWAYS keep your sprites within the Fitviewport? How to keep a reference to the view in order to have the proper coordinates as to where to draw?
I'm trying to spawn enemies into the gameplay screen. But this is handled by a FitViewport, and enemies and even the player can move outside the FitViewport on certain screen resolutions. So far the problem seems to be in the Y axis.
The FitViewport is made like this:
gameCamera = new OrthographicCamera();
gameCamera.setToOrtho(false);
gameViewport = new FitViewport(MyGame.WORLD_WIDTH,MyGame.WORLD_HEIGHT,gameCamera);
gameViewport.setScreenBounds(0,0,MyGame.WORLD_WIDTH,MyGame.WORLD_HEIGHT);
Then the camera position gets updated like this at the resize() method:
gameViewport.update(width,height); //not used when using the virtual viewport in the render method.
gameCamera.position.set(player.position.x + 200,player.position.y, 0);
Then the update() method calls the Player's own update() method which includes these lines:
//POSITION UPDATE
if (this.position.x<0) this.position.x=0;
if (this.position.x>Gdx.graphics.getWidth() - width) this.position.x= Gdx.graphics.getWidth() - width;
if (this.position.y<0) this.position.y = 0;
if (this.position.y>PlayScreen.gameViewport.getScreenHeight() - height) this.position.y = PlayScreen.gameViewport.getScreenHeight()- height;
Notice for the X axis I'm still using Gdx.graphics dimensions because I'm yet to make it work with PlayScreen.gameViewport.getScreenHeight() (gameViewport has been set to static for this purpose).
Also on enemy spawn (the problem related here is that they spawn outside of the screen Y in terms of what I see) I have this code inside the update() method of the Screen implementing all these viewports:
//Alien Spawn
if (System.currentTimeMillis() - lastZSpawn >= SpawnTimer){
count++;
lastZSpawn= System.currentTimeMillis();
for (int i=0;i<count;i++){
int x = Gdx.graphics.getWidth();
int y = random.nextInt((int)gameViewport.getScreenHeight() - Alien.height);
if (entities.size()<6){
entities.add(new Alien(new Vector2(x,y),1, alienImages,(float)((0))));
}
}
}
Also using gameViewport.getScreenHeight() here cause Gdx.graphics wasnt giving the correct result (it gave me the same issue really).
The render() method is correctly implemented in terms of the batch and applying the viewport:
MyGame.batch.setProjectionMatrix(gameCamera.combined);
gameViewport.apply();
MyGame.batch.begin();
for (int i = entities.size()-1; i>=0;i--){
entities.get(i).render();
}

You should never change the position of your player or enemies when resizing, that's why a viewport is for, remove all the code that do that first, to make your viewport work as you expected you need to create a new instance of camera passing the new viewport width and height when you resize, i prefer to make my camera static so i can acess its atribbutes from everywhere i want, you should do something like this:
public static OrthographicCamera update(int width,int height){
instance = new OrthographicCamera(width, height);
instance.setToOrtho(false);
return instance;
}

The answer to my problem is posted by myself in another question of mine which was also driven by a confusion in the implementation of FitViewports and using WorldWidth and WorldHeight properties as coordinates of reference when drawing objects into the game, and also correctly setting the camera position taking these values into consideration aswell.
The answer is here even though its text and not code and its mainly what i already wrote in this very post. FitViewport doesnt scale properly Libgdx

Get width and height of LibGdx animation

How can I get the width and height of a single frame when using LibGdx Animation?
tallAnim = new Animation(1/10f, atlas.findRegion("runner1"), atlas.findRegion("runner2"), atlas.findRegion("runner3"), atlas.findRegion("runner4"));
shortAnim = new Animation(1/10f, atlas.findRegion("short_runner1"), atlas.findRegion("short_runner2"), atlas.findRegion("short_runner3"), atlas.findRegion("short_runner4"));
animation = tallAnim;
I switch between these two animations and when I check for collision I need to know if the exact width/height of the current animation frame.
How I'd normally handle this:
public Rectangle getBounds(){
return new Rectangle(positionX, positionY, sprite.getWidth(), sprite.getHeight());
}

The method atlas.findRegion("path/goes/here") returns a TextureRegion. A TextureRegion has a region.getTexture() method. A Texture has a tex.getWidth() and a tex.getHeight() method. Assuming these frames are the same width, you should be able to just say something like atlas.findRegion("path/goes/here").getTexture().getWidth() and atlas.findRegion("path/goes/here").getTexture().getHeight(). Otherwise you'll need some way to keep track of what frame your on and get the width and height depending on the current frame.
Your method, I'm guessing, should now look something like:
public Rectangle getBounds() {
return new Rectangle(posX, posY, atlas.findRegion("path/goes/here").getTexture().getWidth(), atlas.findRegion("path/goes/here").getTexture().getHeight())
}
I'll provide some links to each of the classes, so you can look through yourself and see what other methods they have.
TextureAtlas documentation: http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/graphics/g2d/TextureAtlas.html
TextureRegion documentation: http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/graphics/g2d/TextureRegion.html
Texture documentation: http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/graphics/Texture.html

LibGDX problems rotating sprite

OK so I'm really confused I've rotated sprites before and had no problem such as rotating a boat as it moves through an ocean, but for some reason I'm having a really big problem this time. So I create a texture in an assets file, but not static textures. I load the texture using the following:
class Assets{
Texture img;
public Assets(){
img = new Texture(Gdx.files.internal("images/PNG.png")
And then I call the assets in the main class by calling:
Assets assets = new Assets()
And then I have a class that is an animator just for this main character because his animation is so different and varied from other characters.
class Animations{
Guy MYGUY;
Texture firstTexture;
ArrayList<Texture> running;
Sprite CurrentSprite;
public Animations(Texture standingStill, Guy myGuy){
MYGUY = myGuy;
firstTexture = standingStill;
running = new ArrayList<Texture>();
running.add(firstTexture);
CurrentSprite = new Sprite(firstTexture);
public void update (int direction, int state){
CurrentSprite.setPosition(MYGUY.X, MYGUY.Y)
// I have a switch here, but it does nothing yet because I haven't added in different actions for the character.
//However I do have a switch for direction, because that is important right now
switch(state){
case Guy.LEFT:
CurrentSprite.set rotation(180);
//yes there are more, but even rotating 180 won't work correctly
}
Then I have a renderer class to draw everything, i have the object MyGuy in an object for the world called myLand and I draw it with:
myLand.GUY.animation.CurrentSprite(batch);
So my problem arises on the rotation, whenever it rotates 180 degrees it seems to always rotate around the coordinates (0, 0) instead of the center of the sprite. So it usually ends up where I move like five to the right, but then if I try to go left it does double the distance backwards, but the camera position stays the same, and the guy usually disappears off the left or right side of the screen.

Try use rotate(...)method instead of setRotation(...).
With setOrigin(widthSprite\2, heightSprite\2)
That action rotate sprite itself.

Try
sprite.setOriginCenter();
This should help

Instead of rotating the sprite, just flip it with this single line:
CurrentSprite.flip(true, false);
the first boolean is X flip (that's what you want to set as true when going left) and the second is the Y flip.

Binding sprite movement to the camera or scene (AndEngine)

I am using DigitalOnScreenControl to Move Player Sprite.But the Problem is that My Player Sprite goes out of Emulator Screen.I want player sprite be restricted to move in particular bounds and also camera to focus on player sprite as and when my sprite moves on.
i am trying this code:
public Scene onLoadScene() {
// Auto-generated method stub
this.mEngine.registerUpdateHandler(new FPSLogger());
final Scene mScene=new Scene();
mScene.setBackground(new ColorBackground(0.09804f, 0.6274f, 0.8784f));
final int centerX=(CAMERA_WIDTH-this.mPlayerTextureRegion.getWidth())/2;
final int centerY=(CAMERA_HEIGHT-this.mPlayerTextureRegion.getHeight())/2;
final Sprite player=new Sprite(centerX, centerY, this.mPlayerTextureRegion);
this.mCamera.setChaseEntity(player);
final PhysicsHandler physicsHandler=new PhysicsHandler(player);
player.registerUpdateHandler(physicsHandler);
mScene.attachChild(player);
this.mDigitalOnScreenControl=new DigitalOnScreenControl(0,CAMERA_HEIGHT-mOnScreenControlBaseTextureRegion.getHeight(),this.mCamera,this.mOnScreenControlBaseTextureRegion,this.mOnScreenControlKnobTextureRegion,0.1f,new IOnScreenControlListener() {
#Override
public void onControlChange(BaseOnScreenControl pBaseOnScreenControl,
float pValueX, float pValueY) {
// TODO Auto-generated method stub
physicsHandler.setVelocity(pValueX*100, pValueY*100);
}
});
this.mDigitalOnScreenControl.getControlBase().setBlendFunction(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);
this.mDigitalOnScreenControl.getControlBase().setAlpha(0.5f);
this.mDigitalOnScreenControl.getControlBase().setScaleCenter(0, 128);
this.mDigitalOnScreenControl.getControlBase().setScale(1.25f);
this.mDigitalOnScreenControl.getControlKnob().setScale(1.25f);
this.mDigitalOnScreenControl.refreshControlKnobPosition();
mScene.setChildScene(this.mDigitalOnScreenControl);
return mScene;
}
Honestly I am Very new in andEngine Development
please Help me With Heart
Thank in advance.

Binding the Player to the Camera
What you're asking for is a form of collision handling. Essentially, when you've moved the player outside of the scene, you want to move the player back into the scene, and you want to do that in the same update as you've moved the player, immediately after moving the player, so the out-of-scene location never gets rendered.
Lets take apart what I just said. You move the player here:
physicsHandler.setVelocity(pValueX*100, pValueY*100);
Moving the player with a physicsHandler is perfectly reasonable and takes into account variable frame-rate so, so far, good job. Now you want to move them back into the scene if they're outside it. So we're going to need a new method. Lets throw in a method call right after moving the player (we'll call it "adjustToSceneBinding()" so you have this:
physicsHandler.setVelocity(pValueX*100, pValueY*100);
adjustToSceneBinding(player);
Sidenote, I'd rather have this method be on the player (i.e., player.adjustToSceneBinding()), but your player object is just a sprite. I'd suggest you change that to a custom object that extends sprite so you can throw in your own code there. In any event, lets make the adjustToSceneBinding() method.
public boolean adjustToSceneBinding(Sprite player) {
// Correct the X Boundaries.
if (player.getX() < 0) {
player.setX(0);
} else if (player.getX() + player.getWidth() > CAMERA_WIDTH) {
player.setX(CAMERA_WIDTH - player.getWidth());
}
}
See what I did? If the player's X coordinate is less than zero, move them back to zero. If the player's X PLUS the player's width is more than the camera width, move them back to the camera width minus the player width. Don't forget the player X coordinate represents the left side of the sprite. That's why I'm taking into account the width in addition to the position for calculating the right side.
The above code only addresses left/right movement, but I'm going to let you extrapolate how to do the same for up down.
Binding the Player to the Map Size Instead
Now, what we did so far was really intended for the situation where the map "size" is no larger than the screen. But often what you'll want is a larger map than the screen size and a camera that chases the player around. To do that, just replace the code above, where I referred to the CAMERA_WIDTH with a number that represents the width of your "map". In other words, the map can be much larger than the camera. If you use larger numbers there (than, say, the width of the camera), and you set the camera to chase the player entity (as you have), then you'll have a map where the player can move around until they hit the bounds of the map.
Hope this helps! :)

LibGdx How to repeat background?

Few days ago I figured out how to do some scrolling in LibGdx. Now I'm triying to do something related. I want to repeat the background. My scrolling follows a ship (Is an s[ace ship game). In the background there is a space photo loaded as a Texture. When the ship reach the end of the backgorund, It keeps going and there's no background anymore. I have read about wrap but I don't really understand How It works. I did that:
px=new Pixmap(Gdx.files.internal("fondo.jpg"));
background=new Texture(px);
background.setWrap(TextureWrap.Repeat, TextureWrap.Repeat);
And then, in my render method
spriteBatch.begin();
spriteBatch.draw(background,0,0,500,50);
drawShip();
spriteBatch.end();
Of course It doesn't work, It only draws the background once. I don't know how make this wrap method work. Any help?
SOLUTION
I figured It out. It's not a nice code but It works.
First I declare two Textures with the same image
bck1=new Texture(Gdx.files.internal("fondo.jpg"));
bck2=new Texture(Gdx.files.internal("fondo.jpg"));
Also I declare two variables like this to specify the X value of the position of each bck
int posXBck1=0,posXBck2=0;
Then I use that in Render()
public void calculoPosicionFondos(){
posXBck2=posXBck1+ANCHODEFONDO;
if(cam.position.x>=posXBck2+cam.viewportWidth/2){
posXBck1=posXBck2;
}
}
Where:
ANCHODEFONDO is the width of my background
Cam is an OtrhoCam.
So I said that if the cam is in bck2 (wich means that you can't see bck1 anymore) It change positions, giving bck1 de position of bck2 and, in the next render loop, recalculating bck2
Then just paint both bck in your render mode.

Like Teitus said, do not load your texture multiple times, ever! Anyway, you where on the right track with the wrapper:
texture.setWrap(TextureWrap.Repeat, TextureWrap.Repeat);
Now you can just use the draw method with the source location. The source location is the area you choose to draw on the texture.
batch.draw(texture, x, y, srcX, srcY, srcWidth, srcHeight)
To scroll your texture from right to left all you have to do is increase srcX incrementally. So create a int that increments in the update/render method.
int sourceX = 0;
//render() method
//Increment the variable where to draw from on the image.
sourceX += 10;
//Simply draw it using that variable in the srcX.
batch.draw(YourTexture, 0, 0, sourceX, 0, screenWidth, screenHeight);
Because you are wrapping the texture it will wrap/loop and scroll indefinitely. There might be a issue with the sourceX int if the game runs for a very long time because a int can only hold 2147483647. It takes a while but you can fix it by subtracting the image width each time the number goes over the total image width.

Don't to this, please:
bck1=new Texture(Gdx.files.internal("fondo.jpg"));
bck2=new Texture(Gdx.files.internal("fondo.jpg"));
That will load your big background texture twice. That's a complete waste. If you want to keep your solution at least do:
bck1=new Texture(Gdx.files.internal("fondo.jpg"));
bck2=bkg1;
Regarding the texture Wrapping. If your texture is 500px wide, and you draw a 500px sprite, you won't see any repetition. If you want it repeated 2 times, draw it 1000px wide with 0-2 texture coordinates.
I'm not sure how spriteBatch handles the call you posted, you could try that one, or may be use the overload that uses a texture region and set your region manually.

I see this is a pretty old question, but I think there is an easier way to accomplish background scrolling. Just use the Sprite class. Here is a snippet I use for layered background images that scroll from right to left.
public class LevelLayer
{
public float speedScalar = 1;
private List<Sprite> backgroundSprites = new ArrayList<Sprite>();
public LevelLayer()
{
}
public void addSpriteLayer(Texture texture, float startingPointX, float y, int repeats)
{
for (int k = 0; k < repeats; k++)
{
Sprite s = new Sprite(texture);
s.setX(startingPointX + (k*texture.getWidth()));
s.setY(y);
backgroundSprites.add(s);
}
}
public void render(SpriteBatch spriteBatch, float speed)
{
for (Sprite s : backgroundSprites)
{
float delta = s.getX() - (speed * speedScalar);
s.setX(delta);
s.draw(spriteBatch);
}
}
}
Then you can use the same texture or series of textures like so:
someLayer.addSpriteLayer(sideWalkTexture1, 0, 0, 15);
someLayer.addSpriteLayer(sideWalkTexture2, 15 * sideWalkTexture1.getWidth(), 0, 7);
I change background repeating sections randomly in code and make new ones or reset existing sets when they go off screen. All the layers go to a pool and get pulled randomly when a new one is needed.

SOLUTION
I figured It out. It's not a nice code but It works.
First I declare two Textures with the same image
bck1=new Texture(Gdx.files.internal("fondo.jpg"));
bck2=new Texture(Gdx.files.internal("fondo.jpg"));
Also I declare two variables like this to specify the X value of the position of each bck
int posXBck1=0,posXBck2=0;
Then I use that in Render()
public void calculoPosicionFondos(){
posXBck2=posXBck1+ANCHODEFONDO;
if(cam.position.x>=posXBck2+cam.viewportWidth/2){
posXBck1=posXBck2;
}
}
Where:
ANCHODEFONDO is the width of my background
Cam is an OtrhoCam.
So I said that if the cam is in bck2 (wich means that you can't see bck1 anymore) It change positions, giving bck1 de position of bck2 and, in the next render loop, recalculating bck2
Then just draw both bck in your render()