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How to detect collisions properly?

This is my first time making a game with LibGDX and I'm trying to increase the score in my game when two things collide, but it doesn't register the collision at all.
This is what I have in the Player class:
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.TextureRegion;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.Body;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.CircleShape;
import com.badlogic.gdx.physics.box2d.EdgeShape;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.World;
import com.mygdx.summative.MyGdxGame;
import com.mygdx.summative.Screens.PlayScreen;
public class Player extends Sprite {
public World world;
public Body b2dbody;
private TextureRegion peteStand;
public Player(World world, PlayScreen screen ){
super(screen.getAtlas().findRegion("goomba"));
this.world = world;
definePlayer();
peteStand = new TextureRegion(getTexture(), 227,1,16,16);
setBounds(227,1,16/ MyGdxGame.PPM,16/MyGdxGame.PPM);
setRegion(peteStand);
}
public void update (float dt ){
setPosition(b2dbody.getPosition().x - getWidth() /2, b2dbody.getPosition().y - getHeight()/2);
}
public void definePlayer (){
BodyDef bdef = new BodyDef();
bdef.position.set(32 / MyGdxGame.PPM,32 /MyGdxGame.PPM);
bdef.type = BodyDef.BodyType.DynamicBody;
b2dbody = world.createBody(bdef);
FixtureDef fdef = new FixtureDef();
CircleShape shape = new CircleShape();
shape.setRadius(6/MyGdxGame.PPM);
fdef.shape = shape;
b2dbody.createFixture(fdef);
EdgeShape body = new EdgeShape(); // used for collision dectection
body.set(new Vector2(-1/MyGdxGame.PPM,7/MyGdxGame.PPM), new Vector2(1/MyGdxGame.PPM,7/MyGdxGame.PPM)); // sets up borders for collision on player
fdef.shape = body ;
fdef.isSensor = true;
b2dbody.createFixture(fdef).setUserData("body"); // used to identify collisions to see if one if the player
}
}
When cloud hits, I want to increase the score, so I wrote this in the Object class:
public class Cloud extends InteractiveTileObject {
public Cloud(World world, TiledMap map, Rectangle bounds) {
super(world, map, bounds);
fixture.setUserData(this);
}
#Override
public void onBodyHit() {
Gdx.app.log("Cloud" , "Collision");
Hud.addScore(200);
}
}
What am I missing? This is contact methods in the ContactListener class:
#Override
public void beginContact(Contact contact) { // when to things start to collide
// figures out with fixture is which in a collision of two objects
Fixture fixA = contact.getFixtureA();
Fixture fixB = contact.getFixtureB();
// checks of one is players body
if (fixA.getUserData() == "body" || fixB.getUserData() == "body"){
Fixture body = fixA.getUserData() == "body" ? fixA : fixB;
Fixture object = body == fixA ? fixB : fixA;
// checks if the object the player collided with is a interactive object
if (object.getUserData() instanceof InteractiveTileObject) {
((InteractiveTileObject) object.getUserData() ).onBodyHit();
}
}
}

Generally, fixA.getUserData() == "body" is wrong because you are comparing the equality of references. To check if a String is equal to another in terms of the content, i.e. lexicographically you should do fixA.getUserData().equals("body") or a safer way "body".equals(fixA.getUserData()).
On a side note, the "player" identifier may be more suitable, as technically speaking everything in the physics world is a body.

Shaking single tile in java (libgdx + TiledMap)

I'm making a clone of old Super Mario and I am trying to shake the brick tile when mario in his little form hits it from below. The concept is taken from a great libgdx tutorial by Brent Aureli and everything he wrote/shown works, however when I made this (seemingly small) modification, the modification itself behaves strange.
Namely, when little mario hits the tile (any brick tile) ALL tiles of this kind get this offset. From my understanding, the access is getCell().getTile().setOffsetY(value) which should mean
get a single cell -> get tile in that cell -> set offset to this one tile that is in the given cell.
Documentation also suggests it should work like that:
https://libgdx.badlogicgames.com/nightlies/docs/api/
replacing tile with null when big mario hits the tile works as intended, so I don't understand why the approach with getCell.getTile doesn't.
Finally, I'm aware that cells are immobile, all I want is a purely cosmetic shift of the actual texture for half a second or so - and that is possible, but in the current state it offsets ALL similar tiles.
For the fun of it I
public class Brick extends InteractiveTile {
private static TiledMapTileSet tileSet;
public Brick(PlayScreen screen, MapObject object) {
super(screen, object);
tileSet = screen.getMap().getTileSets().getTileSet("tileset_gutter");
fixture.setUserData(this);
setCategoryFilter(SuperMario.BRICK_BIT);
}
#Override
public void onHeadHit(Mario mario) {
if(mario.isBig()){
SuperMario.manager.get("audio/breakblock.wav", Sound.class).play();
setCategoryFilter(SuperMario.DESTROYED_BIT);
getCell().setTile(null);
}
else {
SuperMario.manager.get("audio/bump.wav", Sound.class).play();
// DOES THE EXACT SAME AS LATER 3 LINES
// getCell().getTile().setOffsetY(2);
getCell().setTile(tileSet.getTile(28)); //this can change texture of individual tile.
TiledMapTile tile = getCell().getTile();
tile.setOffsetY(2);
getCell().setTile(tile);
}
}
}
InteractiveTile:
public abstract class InteractiveTile {
private World world;
private TiledMap map;
private TiledMapTile tile;
private Rectangle bounds;
protected Body body;
protected final Fixture fixture;
protected PlayScreen screen;
protected MapObject object;
public InteractiveTile(PlayScreen screen, MapObject object){
this.screen = screen;
this.world = screen.getWorld();
this.map = screen.getMap();
this.object = object;
this.bounds = ((RectangleMapObject)object).getRectangle();
BodyDef bdef = new BodyDef();
FixtureDef fdef = new FixtureDef();
PolygonShape shape = new PolygonShape();
bdef.type = BodyDef.BodyType.StaticBody;
bdef.position.set(
(bounds.getX()+ bounds.getWidth()/2)/ SuperMario.PPM,
(bounds.getY() + bounds.getHeight()/2)/SuperMario.PPM);
body = world.createBody(bdef);
shape.setAsBox(
(bounds.getWidth()/2)/SuperMario.PPM,
(bounds.getHeight()/2)/SuperMario.PPM); fdef.shape = shape;
fixture = body.createFixture(fdef);
}
public abstract void onHeadHit(Mario mario);
public TiledMapTileLayer.Cell getCell(){
TiledMapTileLayer layer = (TiledMapTileLayer) map.getLayers().get(1);
return layer.getCell(
//REVERT SCALING (PPM) AND by tile size
(int)(body.getPosition().x * SuperMario.PPM / 16),
(int)(body.getPosition().y * SuperMario.PPM / 16));
}
public void setCategoryFilter(short filterBit){
Filter filter = new Filter();
filter.categoryBits = filterBit;
fixture.setFilterData(filter);
}
}
is there an error in this code, or it is a limitation of the engine?
PS - the original (unmodified)files can be found on Brent Aurelis github site:
https://github.com/BrentAureli/SuperMario

libGDX - How do I add a (mouse)joint to an Actor in scene2d

If I have a GameStage with the following:
...
public GameStage() {
world = WorldUtils.createWorld();
setUpWorld();
setupCamera();
debugRenderer = new Box2DDebugRenderer();
}
private void setUpWorld() {
world = WorldUtils.createWorld();
world.setContactListener(this);
setupGround();
setupBall();
setupJoint();
}
private void setupBall() {
ball = new Ball(WorldUtils.createBall(world));
addActor(ball);
}
private void setupGround() {
ground = new Ground(WorldUtils.createGround(world));
addActor(ground);
}
private void setupJoint() {
jointDef = new MouseJointDef();
jointDef.bodyA = ???
jointDef.collideConnected = true;
jointDef.maxForce = 50f;
}
...
How do I reference the bodies within each actor so that I can add a joint between two bodies. Specifically I am trying to add a mousejoint to the ball body so that I can add a directional impulse (mousejoint is destroyed in touchup or if max impulse is reached). I set the ground as bodyA during the setupJoint method. In the touchdown method I set the bodyB as the ball. I then find the x and y values (unprojecting them first to move from World to local coordinates) from the touch and set the position of the mouse using jointDef.target.set. My problem is I cannot figure out to get the body from the actor. Here is an example of my createBall method in the WorldUtils class.
...
public static Body createBall(World world) {
// BALL
// Body Definition
BodyDef ballDef = new BodyDef();
ballDef.type = BodyDef.BodyType.DynamicBody;
ballDef.position.set(0, 10); // 1 Meter up not 1 pixel
// Ball shape
CircleShape ballShape = new CircleShape();
ballShape.setRadius(.5f);
// Fixture Definition
FixtureDef fixtureDef = new FixtureDef();
fixtureDef.shape = ballShape;
fixtureDef.density = 2.0f;
fixtureDef.friction = .5f; // 0 to 1
fixtureDef.restitution = .5f; // 0 to 1
Body body = world.createBody(ballDef);
body.createFixture(fixtureDef);
body.resetMassData();
body.setUserData(new BallUserData());
ballShape.dispose();
return body;
}
...
My Ball and Ground are defined like this
...
public class Ground extends GameActor {
public Ground(Body body) {
super(body);
}
#Override
public GroundUserData getUserData() {
return (GroundUserData) userData;
}
}
I am sure I am doing something stupid or I am misunstanding how the connection between scene2d and box2d works.
Thanks

libgdx - implementing moving Kinematic body

project: I am making a simple project in which i want to be able to make a kinematic body and move it from point x to y. There doesn't seem to be much directly on "Creating kinematic bodies". i've been following a few different tutorials on implementing kinematic bodies because i couldnt find one that specified how to do it correctly.
Problem: It seems to be a simple fix but i just can't figure out what the problem is because i don't fully understand how to implement a kinematic body. i believe the problem lies in this code kinematicBody.setLinearVelocity(0.0f, 1.0f); because i get an error in "setLinearVelocity"stating "The method setLinearVelocity(float, float) is undefined for the type BodyDef" i feel that i am doing something wrong here
Outcome i want: i want to be able to create a kinematic body that moves from point x to point y.
here is my relevant code:
package com.mohamed.JungleFighter;
import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Game;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.physics.box2d.BodyDef;
import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;
import com.badlogic.gdx.physics.box2d.Box2DDebugRenderer;
import com.badlogic.gdx.physics.box2d.CircleShape;
import com.badlogic.gdx.physics.box2d.FixtureDef;
import com.badlogic.gdx.physics.box2d.PolygonShape;
import com.badlogic.gdx.physics.box2d.World;
import com.sun.xml.internal.ws.wsdl.writer.document.soap.Body;
public class JungleFighter extends Game {
World world = new World(new Vector2(0, -100), true);
Box2DDebugRenderer debugRenderer;
OrthographicCamera camera;
static final float STEP=1/60f;
static final int VELOCITYITERATIONS=6;
static final int POSITIONITERATIONS=2;
static final float WORLD_TO_BOX=0.01f;
static final float BOX_WORLD_TO=100f;
#Override
public void create() {
camera = new OrthographicCamera();
camera.viewportHeight = 320;
camera.viewportWidth = 480;
camera.position.set(camera.viewportWidth * .5f, camera.viewportHeight * .5f, 0f);
camera.update();
//test platform 3
BodyDef kinematicBody =new BodyDef();
kinematicBody.type = BodyType.KinematicBody;
kinematicBody.position.set(100, 250);
PolygonShape shape = new PolygonShape();
shape.setAsBox(50f, 25f);
fixtureDef.shape = shape;
fixtureDef.density = 0;
fixtureDef.friction = 0;
fixtureDef.restitution = 0;
kinematicBody.setLinearVelocity(0.0f, 1.0f);
// Create our body in the world using our body definition
world.createBody(kinematicBody).createFixture(shape, 50.0f);
shape.dispose();
debugRenderer = new Box2DDebugRenderer();
}
#Override
public void dispose() {
}
#Override
public void render() {
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
debugRenderer.render(world, camera.combined);
world.step(STEP, VELOCITYITERATIONS, POSITIONITERATIONS);
}
#Override
public void resize(int width, int height) {
}
#Override
public void pause() {
}
#Override
public void resume() {
}
}

It appears as if you aren't using the fixtureDef object anywhere. You are supposed to set it to the body once it is created.
The way you create a Kinematic Body isn't much different from a Static Body. The only difference would be how you define the type of the BodyDef.
Create a Kinematic Body
It could be a StaticBody or DynamicBody too. Depends on what you want to accomplish.
BodyDef tempBodyDef = new BodyDef();
tempBodyDef.type = BodyType.KinematicBody;
Create the FixtureDefinition (The one that describes the properties of the fixture)
Also create a shape and assign it to the fixture.
You can modify the firction, isSensor, etc, properties of the tempFD to get the results you want.
FixtureDef tempFD = new FixtureDef();
PolygonShape tempShape = new PolygonShape();
tempFD.shape = tempShape;
The center of the shape for the body will be at 0,0
Vector2 tempVector = new Vector2();
tempVector.x = 0;
tempVector.y = 0;
Setting the size and position of the body's shape.
Notice I'm using half the width and height, as that is what the setAsBox function requires.
tempShape.setAsBox(myWidth/2f, myHeight/2f, tempVector, myAngle);
tempBodyDef.position.set(myXPosition, myYPosition);
Create the body and assign the fixture to it
Body testBody = world.createBody(tempBodyDef);
testBody.createFixture(tempFD);
Don't forget to dispose of the Shape once you are done with it.
tempShape.dispose();
And you are done.

Draw a sprite onto the map not to the screen

I'm using libgdx and I have a tiled map which i want to draw the sprite onto. However the sprite is drawn onto the actual window so when I move the camera, the sprite stays in the same place. ?I want to the sprite to move on the map.
This is how i currently render my objects
#Override
public void render(float delta) {
translateCamera();
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
camera.update();
renderer.setView(camera);
renderer.render(bgLayers);
batch.begin();
batch.draw(splayerSprite, Gdx.graphics.getWidth() / 2,
Gdx.graphics.getHeight() / 2);
batch.end();
renderer.render(fgLayers);
}
It always end up being in the middle of the screen, however I want to be able to move them seperatly like for example the camera with (W,A,S,D) and move my player with the direction keys. Then if I want the camera locks onto the player but other wise its free.
I'm new to libgdx so please bear with me, Thanks

The problem is the SpriteBatch projection matrix isn't being set to the Camera projection matrix. This means the Sprite is not being rendered relative to the Camera. This is why the camera is moving, but the sprite is not; the correct matrix is not being used.
Also the sprite is being rendered always at half the screen's width, and half the screen's height. To fix this Call sprite.draw. This will use the Sprite's internal position.
Set the SpriteBatch projection matrix via batch.setProjectionMatrix(camera.combined). This will cause the sprite to be rendered relative to the camera.
#Override
public void render(float delta) {
translateCamera();
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
camera.update();
renderer.setView(camera);
renderer.render(bgLayers);
//here's the line that was missing.
batch.setProjectionMatrix(camera.combined);
batch.begin();
//be sure to call this instead of specifying position yourself!
splayerSprite.draw(batch);
batch.end();
renderer.render(fgLayers);
}
You'll still need to handle snapping the camera's position to the sprite's position whenever WASD is pressed, but that's trivial.
//snap the camera to the sprite's center.
if(wasd_isDown){
float centerX = sprite.getX()+sprite.getWidth()/2;
float centerY = sprite.getY()+sprite.getHeight()/2;
camera.position.set(x,y, 0);
}
If direction keys are pressed, just translate the camera's position vector via Vector3.add like so:
if(!wasd_isDown){
float deltaX = 0;
float deltaY = 0;
float MOVE_DIST = 10;//or whatever you need.
if(leftPressed) deltaX = -MOVE_DIST;
else if(rightPressed) deltaX = MOVE_DIST;
if(upPressed)deltaY = MOVE_DIST;
else if(downPressed)deltaY = -MOVE_DIST;
camera.position.add(deltaX, deltaY, 0);
}
This will allow the camera to move independently only when the player uses directional keys, and will allow the sprite be be rendered in relation to the camera's orientation. It will also snap the camera immediately back to the sprite when WASD is pressed.

batch.draw(splayerSprite, Gdx.graphics.getWidth() / 2, Gdx.graphics.getHeight() / 2);
You are telling the code to draw it to the center of your screen every time. You need to change Gdx.graphics.getWidth() / 2 and Gdx.graphics.getHeight() / 2 to actual values that change based on your input.
Edit #2: The line batch.setProjectionmatrix(camera.combined); is needed in addition to everything I have mentioned, I both did not notice that specific line was already in my code (it is included in the default libGDX project), and did not try running my demo with that line removed. I hope that clears up any confusion I may have caused.
Edit: Since apparently nobody really liked my answer, I went and wrote a demo using the controls specified in a clean libGDX game. Regardless of where the camera is aimed at (since it is being translated), the sprite was always being rendered in the center of the global screen. It is very much necessary to use the sprite's position in the batch.draw() instead of a static position, otherwise it will not move.
package com.me.mygdxgame;
import com.badlogic.gdx.ApplicationListener;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input.Keys;
import com.badlogic.gdx.graphics.GL10;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.Texture.TextureFilter;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.TextureRegion;
import com.badlogic.gdx.math.Vector2;
public class MyGdxGame implements ApplicationListener {
private OrthographicCamera camera;
private SpriteBatch batch;
private Texture texture;
private Sprite sprite;
private Sprite background;
private boolean lockToSprite;
private Vector2 vecCamera;
private Vector2 vecSprite;
#Override
public void create() {
float w = Gdx.graphics.getWidth();
float h = Gdx.graphics.getHeight();
camera = new OrthographicCamera(w, h);
batch = new SpriteBatch();
lockToSprite = true;
vecCamera = new Vector2();
vecSprite = new Vector2();
texture = new Texture(Gdx.files.internal("data/libgdx.png"));
texture.setFilter(TextureFilter.Linear, TextureFilter.Linear);
TextureRegion region = new TextureRegion(texture, 0, 0, 512, 275);
sprite = new Sprite(region);
sprite.setSize(0.1f * sprite.getWidth(), 0.1f * sprite.getHeight());
sprite.setOrigin(sprite.getWidth()/2, sprite.getHeight()/2);
sprite.setPosition(-sprite.getWidth()/2, -sprite.getHeight()/2);
background = new Sprite(region);
background.setOrigin(background.getWidth() / 2, background.getHeight() / 2);
System.out.println(background.getOriginX());
background.setPosition(-background.getWidth() / 2, -background.getHeight() / 2);
}
#Override
public void dispose() {
batch.dispose();
texture.dispose();
}
#Override
public void render() {
camera.translate(vecCamera);
Gdx.gl.glClearColor(1, 1, 1, 1);
Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
camera.update();
camera.translate(vecCamera.cpy().mul(-1));
float moveSensitivity = 0.9f;
Vector2 vecInputSprite = new Vector2();
if (Gdx.input.isKeyPressed(Keys.UP))
vecInputSprite.y += moveSensitivity;
if (Gdx.input.isKeyPressed(Keys.DOWN))
vecInputSprite.y -= moveSensitivity;
if (Gdx.input.isKeyPressed(Keys.LEFT))
vecInputSprite.x -= moveSensitivity;
if (Gdx.input.isKeyPressed(Keys.RIGHT))
vecInputSprite.x += moveSensitivity;
if (Gdx.input.isKeyPressed(Keys.N))
vecSprite.set(new Vector2());
Vector2 vecInputCamera = new Vector2();
if (Gdx.input.isKeyPressed(Keys.W))
vecInputCamera.y += moveSensitivity;
if (Gdx.input.isKeyPressed(Keys.S))
vecInputCamera.y -= moveSensitivity;
if (Gdx.input.isKeyPressed(Keys.A))
vecInputCamera.x -= moveSensitivity;
if (Gdx.input.isKeyPressed(Keys.D))
vecInputCamera.x += moveSensitivity;
if (Gdx.input.isKeyPressed(Keys.R)) {
vecCamera.set(new Vector2());
lockToSprite = false;
}
if (vecInputCamera.len2() != 0)
lockToSprite = false;
else if (Gdx.input.isKeyPressed(Keys.L))
lockToSprite = true;
if (lockToSprite) {
vecCamera.set(vecSprite);
} else {
vecCamera.add(vecInputCamera);
}
vecSprite.add(vecInputSprite);
batch.setProjectionMatrix(camera.combined);
batch.begin();
background.draw(batch);
sprite.setPosition(vecSprite.x, vecSprite.y);
sprite.draw(batch);
//batch.draw(sprite, vecSprite.x, vecSprite.y);
batch.end();
}
#Override
public void resize(int width, int height) {
}
#Override
public void pause() {
}
#Override
public void resume() {
}
}