Develop Reference

How do I reposition a moving animation during a gameplay?

I am using the Android Studio IDE, with the libGDX framework to develop a game. It is a clone of the Pac-Man game with a similar gameplay to flappy bird. The concept is that the pac man moves through the planks while avoiding the ghosts coming from the right direction, that are moving off straight into the left direction (not chasing the position of the player). I am not sure how I create a 'for loop' for the ghost animations, I want the ghosts to consistently reposition and re-appear from the right side after a few seconds, with the exception that they completely gone off the screen initially.
The class for one of the Ghosts.
public class Blinky {
private Vector3 position; //x y and z axis
private Rectangle bounds;
private Texture texture1;
private Animation blinkyAnimLeft;
public Blinky(int x, int y) {
position = new Vector3(x, y, 0);
Texture texture1 = new Texture("blinkyLeft.png");
blinkyAnimLeft = new Animation(new TextureRegion(texture1), 2, 0.5f);
//bounds = new Rectangle(x,y,texture1.getWidth() / 2, texture1.getHeight());
}
public void update(float dt) {
blinkyAnimLeft.update(dt);
//bounds.setPosition(position.x, position.y);
}
public Vector3 getPosition() {
return position;
}
public TextureRegion getTexture() {
return blinkyAnimLeft.getFrame();
}
//public Rectangle getBounds() {
return bounds;
}
public void dispose() {
texture1.dispose();
}
}
Ghosts and Player initialised in the GamePlayState Class
public class GamePlayState extends State {
//Variables
private float timePassed = 0;
private Texture background;
public static final int WALK = 1;
public static final double GHOST_WALK = 0.5;
private static final int PLANKS_SPACING = 125; //gap betwen the planks
private static final int PLANK_COUNT = 4;
private Array<Obstacle> planks;
private Player player;
private Blinky blinky;
private Inky inky;
private Texture missile;
public GamePlayState(GameStateManager gsm) {
super(gsm);
player = new Player(50, 100);
blinky = new Blinky(400, 220);
inky = new Inky(400, 240);
// missile = new Texture("missile.png");
background = new Texture("black.jpg");
cam.setToOrtho(false, PacMan.WIDTH/2, PacMan.HEIGHT/2);
planks = new Array<Obstacle>();
for (int i = 1; i<= PLANK_COUNT; i++) {
planks.add(new Obstacle(i * (PLANKS_SPACING + Obstacle.PLANK_WIDTH)));
}
}
#Override
public void handleInput() {
}
#Override
public void update(float dt) {
handleInput();
player.update(dt);
blinky.update(dt);
inky.update(dt);
cam.position.x = player.getPosition().x + 80; //update the position of the camera with the bird
//update when pacman cam viewport has passed plank
//make cam follow the player
for (Obstacle plank: planks) {
if (cam.position.x - (cam.viewportWidth/1) > plank.getPosTopPlank().x + plank.getTopPlank().getWidth()) {
plank.respositionPlanks(plank.getPosTopPlank().x + ((Obstacle.PLANK_WIDTH + PLANKS_SPACING * PLANK_COUNT )));
}
if (plank.collision (player.getBounds()))
gsm.set(new GamePlayState(gsm));
}
cam.update();
}
#Override
public void render(SpriteBatch sb) {
sb.setProjectionMatrix(cam.combined);
sb.begin();
sb.draw(background, cam.position.x - (cam.viewportWidth/2), 0);
timePassed += Gdx.graphics.getDeltaTime();
//Moving Inky
sb.draw(inky.getTexture(), inky.getPosition().x, inky.getPosition().y);
inky.getPosition().x -= GHOST_WALK;
//Moving Blinky
sb.draw(blinky.getTexture(), blinky.getPosition().x, blinky.getPosition().y);
blinky.getPosition().x -= GHOST_WALK;

You should get x, y( and z) position from Vector3.
Then check for borders
if (inky.getPosition().x < 0){
Thread.sleep(/*a few sdeconds*/2000);/*Android studio would ask you about wrapping it with try - catch*/
inky.setPostion( x + /*screen x size*/,
inky.getPosition().y,inky.getPosition().z)/*add setter in ghost class*/
}
In fact, this is not the best way to do it, but the simplest one

Stage camera won't move

In my game, I have my objects represented as a actors, thus all of the game objects would be on a Stage. For some reason when I try to move the Stage's camera around, it won't work, or actually it doesn't seem to work. I have added a game Actor to the location of 0,0. When I translate the camera's position around, the Actor still stays at the bottom left corner, despite when I log the camera's position, it shows that the camera has moved.
public class Striker extends Actor {
private Sprite img;
private World worldRef;
private Body body;
//constructor
public Striker(float size, float x, float y, World world) {
img = new Sprite(new Texture(Gdx.files.internal("Striker.png")));
//mains the aspect size ratio
img.setSize((275f / 300f) * size, size);
img.setPosition(x, y);
worldRef = world;
//set up the physics
BodyDef bodyDef = new BodyDef();
bodyDef.type = BodyDef.BodyType.DynamicBody;
bodyDef.position.set(x,y);
body = world.createBody(bodyDef);
}
#Override
public void draw(Batch batch, float parentAlpha) {
img.draw(batch);
}
#Override
public void act(float delta) {
super.act(delta);
}
#Override
public float getX() {
return body.getPosition().x;
}
#Override
public float getY() {
return body.getPosition().y;
}
#Override
public float getWidth() {
return img.getWidth();
}
#Override
public float getHeight() {
return img.getHeight();
}
}
The results of the 2 logs show that the camera's positions have moved, but it doesn't look like it.
public class StrikerScreen implements Screen {
public static float WIDTH = 1920;
public static float HEIGHT = 1080;
public static float PPM = 200;
private Launcher launcherRef;
private OrthographicCamera camera;
private FitViewport viewport;
private World world;
private Box2DDebugRenderer debugRenderer;
private Striker striker;
private Stage gameStage;
//constructor
public StrikerScreen(Launcher launcher) {
launcherRef = launcher;
world = new World(new Vector2(0, -9.8f), true);
debugRenderer = new Box2DDebugRenderer();
gameStage = new Stage();
camera = (OrthographicCamera) gameStage.getCamera();
viewport = new FitViewport(WIDTH / PPM, HEIGHT / PPM, gameStage.getCamera());
viewport.apply();
gameStage.setViewport(viewport);
striker = new Striker(160f / PPM, 0, 0, world);
gameStage.addActor(striker);
gameStage.getCamera().translate(viewport.getWorldWidth() / 2f, 500f, 0);
viewport.apply();
camera.update();
Gdx.app.log("StrikerScreen.java", "Camera position: " + gameStage.getCamera().position.toString());
Gdx.app.log("StrikerScreen.java", "Camera size: " + gameStage.getCamera().viewportWidth + ", " + gameStage.getCamera().viewportHeight);
}
#Override
public void show() {
}
public void update(float delta) {
world.step(1 / 30f, 6, 2);
gameStage.act(delta);
}
#Override
public void render(float delta) {
update(delta);
debugRenderer.render(world, camera.combined);
gameStage.draw();
}
#Override
public void resize(int width, int height) {
viewport.update(width, height, true);
}
#Override
public void pause() {
}
#Override
public void resume() {
}
#Override
public void hide() {
}
#Override
public void dispose() {
}
}

In the code you posted, the only times you move the camera are in the StrikerScreen constructor where you explicitly translate it, and in the resize method, where you have called viewport.update(width, height, true); Passing true to viewport.update tells it to move the camera to where (0, 0) is in the bottom left of corner of the viewport. Since resize is automatically called when you set your screen to this screen, that is the most recent position you have set the camera to.

Libgdx updating animation

I'm learning libgdx and currently doing a flappy bird demo. For fun I tried to implement when the score reached a certain number the bird sprite texture will update and change to another color. Instead of using the spritebatch and changing the color through tinting I wanted to create a new texture(png file).
The problem is since it is a sprite it needs to be animated so the wings will flap. When I try and update the texture at runtime it will only work but the animation wont play.
Here is my bird class:
public class Bird {
private static final int GRAVITY = -15;
private static final int MOVEMENT = 100;
private Vector3 position;
private Vector3 velocity;
private Rectangle bounds;
private Animation birdAnimation;
private Texture birdTexture;
private TextureRegion textureRegion;
private Sound flap;
public Bird(int x, int y){
position = new Vector3(x, y, 0);
velocity = new Vector3(0, 0, 0);
textureRegion = new TextureRegion(returnTexture());
birdAnimation = new Animation(textureRegion, 3, 0.5f);
bounds = new Rectangle(x, y, returnTexture().getWidth() / 3, returnTexture().getHeight());
flap = Gdx.audio.newSound(Gdx.files.internal("sfx_wing.ogg"));
}
public void update(float dt){
textureRegion = new TextureRegion(returnTexture());
birdAnimation = new Animation(textureRegion, 3, 0.5f);
birdAnimation.update(dt);
if(position.y > 0){
velocity.add(0, GRAVITY, 0);
}
velocity.scl(dt);
position.add(MOVEMENT * dt, velocity.y, 0);
if(position.y < 0){
position.y = 0;
}
velocity.scl(1/dt);
bounds.setPosition(position.x, position.y);
}
public TextureRegion getTexture() {
return birdAnimation.getFrame();
}
public Texture returnTexture(){
if(PlayState.score > 1){
return birdTexture = new Texture("birdanimation1.png");
}else{
return birdTexture = new Texture("birdanimation.png");
}
}
public Vector3 getPosition() {
return position;
}
public void jump(){
velocity.y = 250;
flap.play(0.15f);
}
public Rectangle getBounds(){
return bounds;
}
public void dispose(){
returnTexture().dispose();
flap.dispose();
}
}
Here is my animation class:
public class Animation {
private Array<TextureRegion> frames;
private float maxFrameTime;
private float currentFrameTime;
private int frameCount;
private int frame;
public Animation(TextureRegion region, int frameCount, float cycleTime){
frames = new Array<TextureRegion>();
int frameWidth = region.getRegionWidth() / frameCount;
for(int i = 0; i < frameCount; i++){
frames.add(new TextureRegion(region, i * frameWidth, 0, frameWidth, region.getRegionHeight()));
}
this.frameCount = frameCount;
maxFrameTime = cycleTime / frameCount;
frame = 0;
}
public void update(float dt){
currentFrameTime += dt;
if(currentFrameTime > maxFrameTime){
frame++;
currentFrameTime = 0;
}
if(frame >= frameCount){
frame = 0;
}
}
public TextureRegion getFrame(){
return frames.get(frame);
}
}
Here's my render code in my play state:
#Override
public void render(SpriteBatch sb) {
sb.setProjectionMatrix(cam.combined);
sb.begin();
sb.draw(bg, cam.position.x - (cam.viewportWidth /2), 0);
sb.draw(bird.getTexture(), bird.getPosition().x, bird.getPosition().y);
for(Tube tube : tubes){
sb.draw(tube.getTopTube(), tube.getPosTopTube().x, tube.getPosTopTube().y);
sb.draw(tube.getBottomTube(), tube.getPosBotTube().x, tube.getPosBotTube().y);
}
sb.draw(ground, groundPos1.x, groundPos1.y);
sb.draw(ground, groundPos2.x, groundPos2.y);
font.draw(sb, text, cam.position.x - gl.width / 2, cam.position.y + 200);
sb.end();
}
If you need any other classes just ask. I'm probably making a stupid mistake or just coding it entirely wrong for what I'm trying to achieve.
Thanks, Jackson

You need to NOT load your textures every single frame.
libgdx has its own Animation class so you don't need to make your own.
Here is an example on animation from libgdx's github:
2D Animation
To make it simple, just have 2 animaitons on Bird and switch between them when you need to.

Rectangles are not colliding?

Player Class
public class Player extends Sprite implements InputProcessor {
public Vector2 velocity = new Vector2();
private float speed = 500;
public Rectangle rectangle;
public Player(Sprite sprite){
super(sprite);
this.rectangle = sprite.getBoundingRectangle();
}
public void draw(SpriteBatch spriteBatch){
update(Gdx.graphics.getDeltaTime());
super.draw(spriteBatch);
}
public void update(float delta) {
rectangle = new Rectangle(getX() + velocity.x * delta,0,rectangle.getWidth(),rectangle.getWidth());
setX(getX() + velocity.x * delta);
}
}
PlayScreen Class
public class PlayScreen implements Screen {
private Player player;
private OrthographicCamera camera;
private OrthogonalTiledMapRenderer renderer;
private TiledMap map;
private Rectangle rightRectangle, leftRectangle, playerRectangle;
//private ShapeRenderer shapeRenderer;
#Override
public void render(float delta) {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
renderer.render();
renderer.getSpriteBatch().begin();
player.draw(renderer.getSpriteBatch());
renderer.getSpriteBatch().end();
//shapeRenderer.begin(ShapeType.Filled);
//shapeRenderer.setColor(0, 1, 0, 1);
//shapeRenderer.rect(
// player.getX() + player.velocity.x * delta, 0,
// player.rectangle.getWidth(), player.rectangle.getHeight());
//shapeRenderer.end();
}
#Override
public void resize(int width, int height) {
camera.viewportWidth = width;
camera.viewportHeight = height;
camera.update();
}
#Override
public void show() {
camera = new OrthographicCamera();
map = new TiledMap();
renderer = new OrthogonalTiledMapRenderer(map);
//shapeRenderer = new ShapeRenderer();
player = new Player(new Sprite(new Texture("img/player.png")));
rightRectangle = new Rectangle(1280,0,0,720);
leftRectangle = new Rectangle(0,0,0,720);
boolean wallLeft = leftRectangle.overlaps(player.rectangle);
boolean wallRight = rightRectangle.overlaps(player.rectangle);
if(wallLeft){
System.out.println("wallLeft Overlap");
player.velocity.x = 0;
}
else if(wallRight){
System.out.println("wallRight Overlap");
player.velocity.x = 0;
}
player.setPosition(
Gdx.graphics.getWidth()/2f - player.getWidth()/2f,
Gdx.graphics.getHeight()/2f - player.getHeight()/2f
- Gdx.graphics.getHeight()/5f);
}
}
Doesn't seem to be colliding correctly. The rightRectangle and leftRectangle are my screen side bounds. When I use the shapeRenderer, it produces the ShapeRendered rectangle and it will follow my player around. However, I believe that my player.rectangle is not moving at all for some reason, resulting in it not colliding with my side bounds. Any help would be greatly appreciated!

rightRectangle = new Rectangle(1280,0,0,720);
leftRectangle = new Rectangle(0,0,0,720);
A Rectangle is defined as Rectangle(x, y, width, height). It looks like you are trying to define it incorrectly as Rectangle(x1, y1, x2, y2). In the above, you have created two rectangles of 0 width.

libgdx drag and drop

Im trying to add drag and drop functionality to several images in Libgdx. I have looked at this example: https://github.com/libgdx/libgdx/blob/master/tests/gdx-tests/src/com/badlogic/gdx/tests/DragAndDropTest.java but Its still not working. The images do not drag and drop. Would anyone be able to give me some pointers in why its not working?
Thanks
private void createButton() {
stage = new Stage();
Gdx.input.setInputProcessor(stage);
skin = new Skin();
skin.add("up", new Texture(Gdx.files.internal("assets/data/up.png")));
skin.add("def", new Texture(Gdx.files.internal("assets/data/Goal.png")));
final Image up = new Image(skin, "up");
up.setBounds(1090, 630, 40, 40);
stage.addActor(up);
Image def = new Image(skin, "def");
def.setBounds(1090, 585, 40, 40);
stage.addActor(def);
DragAndDrop dragAndDrop = new DragAndDrop();
dragAndDrop.addSource(new Source(up) {
public Payload dragStart (InputEvent event, float x, float y, int pointer) {
Payload payload = new Payload();
payload.setObject(payload);
payload.setDragActor(up);
payload.setDragActor(new Label("up", skin));
Label validLabel = new Label("up", skin);
validLabel.setColor(0, 1, 0, 1);
payload.setValidDragActor(validLabel);
return payload;
}
});
dragAndDrop.addTarget(new Target(def) {
public boolean drag (Source source, Payload payload, float x, float y, int pointer) {
getActor().setColor(Color.GREEN);
return true;
}
public void reset (Source source, Payload payload) {
getActor().setColor(Color.WHITE);
}
public void drop (Source source, Payload payload, float x, float y, int pointer) {
System.out.println("Accepted: " + payload.getObject() + " " + x + ", " + y);
}
});
render();
}
public void render () {
stage.act(Gdx.graphics.getDeltaTime());
stage.draw();
Table.drawDebug(stage);
}

I implemented your code on a project of mine.
I removed your render and used the one below. Also, you shouldn't need the assets/ prefix to your image import.
skin.add("up", new Texture(Gdx.files.internal("images/coin.png")));
skin.add("def", new Texture(Gdx.files.internal("images/coin.png")));
#Override
public void render(float delta) {
super.render(delta);
stage.draw();
stage.act(Gdx.graphics.getDeltaTime());
}

Another way to do drag in a better way...
public class CaveInterection implements ApplicationListener {
private OrthographicCamera camera;
private SpriteBatch batch;
private Texture bgTexture;
private Sprite sprite;
private Stage stage;
private Texture mirrTexture;
private MyActor mirrorActor;
Sprite img1,img2;
#Override
public void create() {
camera = new OrthographicCamera(1024, 550);
camera.position.set(1024 / 2, 550 / 2, 0);
batch = new SpriteBatch();
stage = new Stage(1024, 550, false);
//bgTexture = new Texture(Gdx.files.internal("data/cave.jpg"));
//bgTexture = new Texture(Gdx.files.internal("data/bg.jpg"));
mirrTexture = new Texture(Gdx.files.internal("data/mirror.png"));
mirrTexture
.setFilter(TextureFilter.Linear, TextureFilter.Linear);
mirrorActor = new MyActor(new TextureRegion(mirrTexture));
mirrorActor.setPosition(700, 400);
mirrorActor.setOrigin(mirrorActor.getWidth()/2, mirrorActor.getHeight()/2);
stage.addActor(mirrorActor);
// finally stage as the input process
Gdx.input.setInputProcessor(stage);
}
#Override
public void dispose() {
batch.dispose();
//bgTexture.dispose();
}
#Override
public void render() {
// clear the screen, update the camera and make the sprite batch
// use its matrices.
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
camera.update();
batch.setProjectionMatrix(camera.combined);
batch.begin();
//batch.draw(bgTexture, 0,0);
// Gdx.app.log("arvind","X :"+mirrorActor.getX()+ " Y :"+mirrorActor.getY());
//batch.draw(bgTexture, 0, 0);
batch.end();
// tell the stage to act and draw itself
stage.act(Gdx.graphics.getDeltaTime());
stage.draw();
}
public class MyActor extends Actor {
TextureRegion region;
float lastX;
float lastY;
public MyActor (TextureRegion region) {
this.region = region;
setWidth(region.getRegionWidth());
setHeight(region.getRegionHeight());
addListener(new InputListener() {
public boolean touchDown (InputEvent event, float x, float y, int pointer, int button) {
Gdx.app.log("arv", "pointer1+"+pointer);
// we only care for the first finger to make things easier
if (pointer != 0) return false;
// record the coordinates the finger went down on. they
// are given relative to the actor's corner (0, 0)
Gdx.app.log("arvind", "touchDown");
Gdx.app.log("arv", "pointer2+"+pointer+""+x+"::::"+y);
lastX = x;
lastY = y;
return true;
}
public void touchDragged (InputEvent event, float x, float y, int pointer) {
// we only care for the first finger to make things easier
if (pointer != 0) return;
Gdx.app.log("arv", "touchDragged");
// adjust the actor's position by (current mouse position - last mouse position)
// in the actor's coordinate system.
translate(x - lastX, y - lastY);
// rotate(2);
// save the current mouse position as the basis for the next drag event.
// we adjust by the same delta so next time drag is called, lastX/lastY
// are in the actor's local coordinate system automatically.
lastX = x - (x - lastX);
lastY = y - (y - lastY);
}
});
}
#Override
public void draw (SpriteBatch batch, float parentAlpha) {
//batch.draw(region, getX(), getY());
batch.draw(region, getX(), getY(), mirrorActor.getOriginX(), mirrorActor.getOriginY(), mirrorActor.getWidth(), mirrorActor.getHeight(), 1, 1,getRotation(), true);
}
}
#Override
public void resize(int width, int height) {
}
#Override
public void pause() {
}
#Override
public void resume() {
}
}