Andengine: PhysicsFactory.createCircleBody is creating a square body.. why?

Question

I'm using this to create a player body

private void addPlayer(){ 
        // viral -- add player
        final float startX = (CAMERA_WIDTH - this.mPlayerTextureRegion
                .getWidth()) / 2;
        final float startY = CAMERA_HEIGHT + 100;
        this.playerFace = new Sprite(startX, startY, this.mPlayerTextureRegion,
                this.getVertexBufferObjectManager());
        this.playerBody = PhysicsFactory.createCircleBody(this.mPhysicsWorld,
                playerFace, BodyType.DynamicBody, FIXTURE_DEF);
        final PhysicsHandler physicsHandler = new PhysicsHandler(playerFace);
        playerFace.registerUpdateHandler(physicsHandler);
        playerBody.setBullet(true);

        playerFaceHalfWidth = playerFace.getWidth() / 2;
        playerFaceHalfHeight = playerFace.getHeight() / 2;

        this.mScene.attachChild(playerFace);
        playerFace.setY(CAMERA_HEIGHT - playerFaceHalfHeight * 2);
    }

This is how I'm detecting collision with other sprites:

protected void onManagedUpdate(float pSecondsElapsed) {
                if (playerFace.collidesWith(this)) {
                    // safe of touching border - else game over
                    if (!isPlayerInSafeZone()) {
                        Log.w("cd", "Game Over");
                        isGameInProgress = false;
                        mScene.setIgnoreUpdate(true);
                        processLevelEnd();
                    }
                }
            };

The issue now is that even though i've added a circle body, the collision is detected with the player when the other sprites touch the corner of the png for player. it is a transparent area and the image has only a circle in it for which the body was created. Why is this happening? What is wrong in the above code?

::Update based on Lucaz's inputs:

This is my contactlistener

private ContactListener createContactListener()
{
ContactListener contactListener = new ContactListener()
{
    @Override
    public void beginContact(Contact contact)
    {
        final Fixture x1 = contact.getFixtureA();
        final Fixture x2 = contact.getFixtureB();
        final String x1id = (String) x1.getBody().getUserData();
        final String x2id = (String) x2.getBody().getUserData();
        Log.w("cd", "x1 = " + x1id + " --- x2 = " + x2id);
    }

    @Override
    public void endContact(Contact contact)
    {

    }

    @Override
    public void preSolve(Contact contact, Manifold oldManifold)
    {

    }

    @Override
    public void postSolve(Contact contact, ContactImpulse impulse)
    {

    }
};
return contactListener;
}

This is how I'm setting the user data for the player and other sprites:

Player:

    this.playerFace = new Sprite(startX, startY, this.mPlayerTextureRegion,
            this.getVertexBufferObjectManager());
    this.playerBody = PhysicsFactory.createCircleBody(this.mPhysicsWorld,
            playerFace, BodyType.DynamicBody, FIXTURE_DEF);
    playerBody.setBullet(true);
    playerBody.setUserData("player");

other sprites (balls):

    body = PhysicsFactory.createCircleBody(this.mPhysicsWorld, face,
            BodyType.DynamicBody, FIXTURE_DEF);
    body.setLinearVelocity(vector2);
    body.setBullet(true);
    body.setUserData("ball");

This is how i added the listener to physics world

this.mPhysicsWorld.setContactListener(createContactListener());

The listener is written to print the user data for colliding objects:

but when a sprite collides with player i get null for the player but user data for the other sprite as shown below... how to fix this?

x1 = null --- x2 = ball

After switching to ContactListner it is detecting collision between all sprites except the player .... :-( (the most important one) ... whats wrong with the way the player body/face is setup? — AndroidMechanic - Viral Patel

Łukasz Motyczka Łukasz Motyczka · Accepted Answer · 2015-04-09T06:03:33

its because collidesWith() method is checking collisions of sprites, and not bodies. So it checks if two sprites overlap (even if they are png images, they will stll be treated as not transparent rectangles). To check collisions between bodies there is another way:

private ContactListener createContactListener()
{
ContactListener contactListener = new ContactListener()
{
    @Override
    public void beginContact(Contact contact)
    {
        final Fixture x1 = contact.getFixtureA();
        final Fixture x2 = contact.getFixtureB();
    }

    @Override
    public void endContact(Contact contact)
    {

    }

    @Override
    public void preSolve(Contact contact, Manifold oldManifold)
    {

    }

    @Override
    public void postSolve(Contact contact, ContactImpulse impulse)
    {

    }
};
return contactListener;
}

Please look this simple tutorial:

http://www.matim-dev.com/handling-collisions-between-bodies.html

Andengine: PhysicsFactory.createCircleBody is creating a square body.. why?

1 Answers