Jbox2d Issues with positioning platforms

Question

I am working on developing a platformer, and everything's working fine, except, I seem to be unable to position the bodies for the static platforms.

    // creating all the bodies
    BodyDef bdef = new BodyDef();
    bdef.position.set(x, y);
    bdef.type = BodyType.STATIC;
    Body body = world.createBody(bdef);

    PolygonShape shape = new PolygonShape();
    shape.setAsBox(width, height);      
    FixtureDef fdef = new FixtureDef();
    fdef.friction = 0.3f;
    fdef.shape = shape;
    body.createFixture(fdef);

This is general code that's used to create every body in the map. The bodies work fine, but they don't line up with the width nor the coordinates of the map that I've set. I've noticed that I must specify the bottom left point as starting point for it to make body, but what else I am missing? Why bodies tend to be bigger and go past the starting point of X and Y?

Answer 1

Bodies in box2d are made from their center points. When you define it's position, you are setting it's center and when you define it's width/height, you are actually setting half the width/height (i.e. the size ends up double what you intended).